Abstract

We apply a rigorous dipole model to analyze the light outcoupling and angular performance of quantum dot light emitting diode (QLED). To illustrate the design principles, we use a red QLED as an example and compare its performance with an organic light emitting diode (OLED). By combining a high refractive index glass substrate with macroextractors, our simulation results indicate that the light outcoupling efficiency is doubled from ~40% to ~80%. After analyzing the light emission spectra and angular radiation pattern of the device, we confirm that QLED has a much weaker color shift than OLED.

© 2014 Optical Society of America

1. Introduction

Organic Light-Emitting Diodes (OLEDs) have been widely used in smartphones and tablets [1], and general lighting [2]. However, OLEDs still suffer from a relatively short lifetime [3–5]. Under such circumstance, colloidal quantum dots (QDs) are emerging as a strong contender to overcome the lifetime issue because they are inorganic [6–10] and in the meantime QDs can be utilized for lasing applications [11]. Recently, the demonstration of a highly efficient top-emitting flexible QLED indicate that QLED is also catching up with OLED in the next generation flexible display [12]. Currently, two types of QD operation mechanisms have been realized: photoluminescence (PL) and electroluminescence (EL). The PL type is usually integrated into LCD backlight [13]. In this paper, we focus on the EL type, namely quantum-dot light emitting diode (QLED). The main differences between QLED and OLED are twofold: 1) QLED has symmetric and Gaussian-like emission spectra with a full width half maximum (FWHM) typically as narrow as 30 nm, while for OLED the spectrum is usually broader (~100nm) and more asymmetric [14]. Narrower emission spectra lead to a wider color gamut and more saturated colors [15, 16]. 2) In an OLED, all organic charge transport layers are the mainstream [17]; while in a QLED the hybrid organic-inorganic charge transport layers are preferred to ensure high efficiency [14, 18]. Because these inorganic materials, such as ZnO and TiO2, usually have higher refractive indices than the organic layers [19], they will influence the light outcoupling of QLED structures.

A critical technical challenge of EL device is that its light output is affected by the External Quantum Efficiency (EQE); the highest EQE an EL device can achieve is limited by the light outcoupling efficiency of the device [2, 20, 21], which can be estimated from 1/(2n2) for planar structures without outcoupling enhancement [22, 23], where n is the refractive index of the emitting material. For example, if the refractive index of the emitting medium is 1.7, then only ~17% of the total radiated power can be extracted out, while the remaining 83% is wasted and cannot be utilized. Such ceiling effect illustrates the importance for enhancing the light extraction of QLED structures.

Besides light outcoupling efficiency, the quantum yield of QD materials also plays an important role affecting EQE [24]. While the quantum yield of QLED is mainly determined by the material itself, the light outcoupling efficiency is primarily governed by the device structure. Presently many research efforts are focused on analyzing and improving the intrinsic quantum yield [9, 25, 26], there are few publications dealing with the outcoupling of QLED. However, if we trace back the LED and OLED development histories, in the beginning research is often concentrated on material exploration. But once the material development reaches a mature stage [27], more efforts are delved into device optimization [28]. QLED is expected to follow the same trend. Recently, a red QLED with 90% IQE has been demonstrated [19]. This IQE is comparable to that of the state-of-the-art OLED stacks, suggesting that the outcoupling efficiency will soon become the bottleneck of these highly efficient QLEDs. In this paper, we utilize the dipole model [22] to analyze the outcoupling of QLEDs. In the meantime, we discuss the light emission spectra, color shift, and angular radiation pattern of the QLED structure. A well-known bottom-emitting OLED (BOLED) is used as benchmark for comparison.

2. Device structures

Figure 1(a) depicts the device structure of the inverted bottom-emitting QLED. It consists of a 40nm ITO (indium-tin-oxide) cathode, a 45nm zinc oxide electron-transporting layer (ETL), a 45nm cadmium selenide-cadmium sulfide (core-shell) quantum dot layer as the emitting layer (EML), a 65nm NPB hole transporting layer (HTL), a 15nm HAT-CN hole injection layer (HIL) and a 100nm Al anode. Such structure is similar to the structure proposed in [19], and we compare our numerical results to the experimental results reported in [19]. The intrinsic irradiance of the quantum dot layer is assumed to be the same as the PL spectra of the red quantum dots, as Fig. 1(b) shows, which is also taken from [19]. The emission is narrowband with FWHM~30 nm. The refractive indices of each layer are taken from literature [29–31].

 figure: Fig. 1

Fig. 1 (a) Structure of the proposed QLED stack and (b) PL spectra of the QDs taken from [19].

Download Full Size | PPT Slide | PDF

Figure 2(a) shows the BOLED structure. It consists of a 90-nm ITO anode, 60-nm NHT-5 doped with NDP-2 as HIL and HTL layer, 40-nm Cs-doped BPhen layer as electron injection layer (EIL) and ETL layer. To confine electrons in the EML layer, a 10-nm Spiro-TAD layer is used as the electron blocking layer (EBL) and a 10-nm BAlq layer as the hole blocking layer (HBL), the 20-nm EML layer consists of NPB doped with 10% Ir(MDQ)2(acac). A 100-nm silver layer works as cathode. The PL spectrum of the material is shown in Fig. 2(b). This structure is well documented and discussed in [32], so we use it as benchmark for comparison.

 figure: Fig. 2

Fig. 2 (a) The device structure of the OLED stack and (b) the PL spectra of NPB:Ir(MDQ)2(acac) taken from [32].

Download Full Size | PPT Slide | PDF

Before introducing our simulation model, we would like to mention that here we choose red QLED and OLED as examples because they have high IQE at contemporary stage, and thus understanding the outcoupling of red QLED is urgent. For QLEDs with other colors, especially the blue QLED, they are still under active development stage and the IQE is still not high enough [25]. But our optical model can be extended to Blue QLED as well.

3. Simulation model

Two major approaches have been developed for simulating the emission properties of QLED: the simplified cavity model which describes the QLED structure as a Fabry-Pérot cavity [33, 34], and the more rigorous dipole model which describes the quantum dots as isotropic emitters within a multilayer medium. In both models, the multilayer structure is first simplified to a three-layer structure by the transfer matrix approach [35] to calculate the Fresnel coefficients of both top contact and bottom contact, as shown in Fig. 3; here [RT, TT, AT] and [RB, TB, AB ] represent the [reflection, transmittance, absorption] of top and bottom contacts, respectively. For a bottom-emitting EL device, the transmittance of top contact is usually negligible, and a and b are the distance from emitter to top contact and bottom contact, respectively.

 figure: Fig. 3

Fig. 3 Schematic drawing of the simplified three layer structure.

Download Full Size | PPT Slide | PDF

In the cavity model, the emitted irradiance can be expressed as [28, 33]:

I(λ,θ)=1+RT+2RTcos(ϕT+4πneacos(θ)λ)(1RTRB)2+4RTRBsin2(Δϕ2)TBI0(λ).
In Eq. (1), λ is the emission wavelength, θ is the emitting angle in the air, θ’ is the corresponding light propagation angle in the organic layer governed by the Snell’s law, ϕT is the phase shift of the top contact, ne is the refractive index of the organic material, I0(λ) is the intrinsic PL spectra of the QDs, and Δϕ is the phase shift after one cycle, given by
Δϕ=4πnedcos(θ)λϕBϕT.
Again ϕB is the phase shift of the bottom contact. From Eqs. (1) and (2), we can calculate the irradiance spectra of the QLED structure [28].

Although the cavity model is adequate for simulating irradiance spectra and angular emission, it lacks the capability to determine the outcoupling efficiency of the QLED. On the other hand, the dipole model can provide complete information in irradiance spectra, outcoupling efficiency as well as angular dependence [31]. Therefore, here we use the dipole model to evaluate the outcoupling efficiency and the corresponding loss channels of the QLED structure.

The dipole model was first developed to simulate the light emission spectra of OLED, in which the EQE is defined as [20]:

EQE=ηIQE=ηγηS/Tqeff,
where η is the outcoupling efficiency and IQE is the Internal Quantum Efficiency, which is the product of effective quantum yield qeff, charge carrier balance γ, and singlet/triplet capture ratio ηS/T [28].

Similar to OLED, the EQE of an QLED can be expressed as [20]:

EQE=ηIQE=ηγqeff.
In Eq. (4), we omit the singlet/triplet capture ratio term used in OLED because of the large spin-orbit coupling in QDs [36, 37]. The effective quantum yield qeff of an QLED device is closely connected to the intrinsic quantum yield q, which can be further expressed as [25, 38]:
q=krkr+knr,
here kr is the exciton radiative recombination rate and knr is the exciton non-radiative recombination rate.

Similarly, in the dipole model the QLED structure is also simplified to the equivalent three-layer structure shown in Fig. 3. And then the emissive QDs are treated as forced damped harmonic oscillators [22, 23]. The power generated by dipoles within a three-layer structure normalized to the power emitted in an infinite medium is given by [20]:

P=1q+qF=1q+q0K(kx)dkx.
In Eq. (6), q is the intrinsic quantum yield of the QDs, F is the Purcell factor which describes how the cavity effect modifies the exciton recombination rate from kr to kr*, K is the power dissipation density per unit dkx, and kx is the in-plane wave vector for waves propagating in the emitting medium. With Eq. (4) and Eq. (6), we can obtain the relation between qeff and q:

qeffq=kr*kr*+knr=FkrFkr+knr=FqF+1q.

From Eq. (7), we see that the cavity can either increase or reduce qeff with respect to q. Thus QLED stack design is not only important for the outcoupling of light emission, but also vital for enhancing the quantum yield of the QLED device if q is not equal to unity. How the cavity design influences the effective quantum efficiency has been described in detail in [32] and is beyond the scope of this paper. In this paper, our main purpose is to analyze the outcoupling of QLED, so we will assume q = 1 and γ = 1 if not otherwise specified.

Equation (6) is not explicit for calculating the power dissipation spectra and the outcoupling efficiency of the QLED, thus we need to express K explicitly. For the isotropic QDs, K consists of three terms [28]:

K=13KTMv+23(KTMh+KTEh),
and
KTMv=32Re[kx3(1+rTMvbe2ikzb)(1+rTMvte2ikza)kekz3(1rTMvbrTMvte2ikz(a+b))],KTMh=34Re[kxkz(1rTMvbe2ikzb)(1rTMvte2ikza)ke3(1rTMvbrTMvte2ikz(a+b))],KTEh=34Re[kx(1+rTEvbe2ikzb)(1+rTEvte2ikza)kekz(1rTEvbrTEvte2ikz(a+b))].
Here r is the reflection coefficient, subscripts v and h represent the dipoles parallel to the z axis and the x-y plane, respectively, TE and TM stand for transverse electric and transverse magnetic modes, ke = 2πne is the wave vector of the emitting QD layer, kz=ke2kx2 is the wave vector along the z axis in the QD layer, and Re means the real part of the complex number.

From Eqs. (6)-(9), we can calculate the power dissipation spectra of the BOLED and the QLED structures. For example, Fig. 4 shows the power dissipation spectra of both BOLED and QLED at λ = 620nm (the intrinsic quantum yield of both BOLED and QLED is assumed to be unity). From Fig. 4, we can determine from left to right the four optical channels of the BOLED and the QLED: direct emission, substrate mode, waveguide mode, and surface plasmons. These four channels are separated by their in-plane wave vector kx. Details are described as follows: 1) Direct emission: k0·nairkx≥0, where k0 = 2π/λ is the vacuum wave vector, and nair is the refractive index of air. Basically, the direct emission part is determined by the largest in-plane wavevector travelling at 90° in air. 2) Substrate mode: k0·nsubkx>k0·nair, where nsub is the refractive index of glass substrate. In the substrate mode, the light experiences total internal reflection (TIR) at the substrate/air interface and is trapped inside the glass substrate. 3) Waveguide mode: k0·neffkx>k0·nsub, where neff is the real part of the equivalent refractive index of the organic layers, QD layers and ITO layer (the metallic layer and the glass substrate layer are not included). The expression for neff is [20]:

εeff=idi/i(di/εi),neff=Re(εeff).
In Eq. (10), di is the layer thickness, εi is the corresponding complex dielectric constant, and εeff is the equivalent dielectric constant. In this mode, light is guided inside the organic layers because of TIR at the ITO and glass interface. 4) Surface plasmons: kx>k0·neff, this mode corresponds to the evanescent wave at the QD/metal interface.

 figure: Fig. 4

Fig. 4 Simulated power dissipation spectra of (a) QLED and (b) BOLED.

Download Full Size | PPT Slide | PDF

For the four optical channels, part of the dissipated power is absorbed inside the device instead of leaking into the corresponding optical channel, which is explained as follows: from Eq. (9), if kz is real, then KTEh can be rewritten as [22]:

KTEh=38kxkekz[|1+rTEvbe2ikzb|2|1rTEvbrTEvte2ikz(a+b)|2(TTEvt+ATEvt)+|1+rTEvte2ikzt|2|1rTEvbrTEvte2ikz(a+b)|2(TTEvb+ATEvb)]=38kxkekz[|1+rTEvbe2ikzb|2|1rTEvbrTEvte2ikz(a+b)|2(TTEvt+TTEvb)+|1+rTEvte2ikzt|2|1rTEvbrTEvte2ikz(a+b)|2(ATEvt+ATEvb)]=KTEhT+KTEhA.
Here A and T represent the absorption and transmittance, respectively. KTMv and KTMh can also be treated similarly. With this approach, for non-evanescent waves, K can be separated into transmission part KT and absorption part KA, the transmission part is attributed to its corresponding optical channels while the absorption part is attributed to the intrinsic optical absorption, which comes from the intrinsic absorption of the organic and QD layers (for the organic and QD layers, the absorption coefficient κ is not equal to zero). With this approach, we can calculate the five optical channels inside the QLED: direct emission, substrate mode, waveguide mode, surface plasmons, and absorption.

Equation (6) only describes the power dissipation spectra at one wavelength. To calculate the entire spectra, Eq. (6) should be rewritten as follows by taking the normalized PL spectra S(λ) into consideration [20]:

P=1q+qF=1q+qλ1λ2S(λ)0K(kx)dkxdλ.
Equation (12) provides a way to calculate the total dissipated power of the QLED and the BOLED structure across the entire visible range (from λ1 = 400nm to λ2 = 800nm).

Before we compare the QLED and the BOLED, we would like to emphasize that even though the two metallic electrodes used in QLED and OLED are different and they have different work functions, both of them can achieve high IQE (close to unity), as is demonstrated in [19] and [32], respectively. In our analysis we assume an IQE of unity to emphasize on the outcoupling properties of the devices, and thus the difference between a silver electrode and aluminum electrode is that their different refractive indices means different reflectivity of the top contact, which will finally affect the outcoupling of the QLED and the OLED. In our QLED and OLED structures, at the thickness of 100nm, both the silver electrode and the aluminum electrode are highly reflective. The similarity of the top contacts’ reflectivity is the key issue why we can compare the QLED with the OLED even though they use different metals.

By analyzing the borders between different channels [32], it is possible to determine the ratio of different optical channels for the QLED and BOLED structures, as Fig. 5 illustrates.

 figure: Fig. 5

Fig. 5 Amount of power coupled to different optical channels for (a) QLED device and (b) BOLED device.

Download Full Size | PPT Slide | PDF

Without any additional outcoupling structure, only the direct emission part can be extracted. The relationship between directly emitted power Pdir and total radiated power Ptot is [20]:

qeffη=Pdir/Ptot.
If we assume qeff = 1, then it is simple to deduce from Fig. 5 that the EQE of QLED structure is 19.2%, which matches well the experimental results reported in [19], and this validates our model. Unlike its bulky counterparts, the solution-based CdSe/CdS thin films have a refractive index similar to that of the organic phosphors used in OLED. The relatively low refractive index of the thin films is mainly contributed by the organic ligands [39]. Thus, it is foreseeable that the EQE of the QLED is also limited by the EQE ceiling, which can be estimated as 1/(2n2), where n is the refractive index of the CdSe/CdS layer.

For both the QLED and the BOLED, the direct emission part contributes to ~20% of the total radiated power. However, it is obvious that the waveguide mode in QLED contributes more to the total radiated power compared to BOLED (36.1% vs. 7.6%). The main reason for this enhanced waveguide mode is that the refractive index of the ZnO layer (~2.0) is larger than that of the organic layer (~1.8) [18]. Thus, the waveguiding effect between the glass substrate and the QLED stacks is stronger than that of the OLED structure with all organic layers. Such a difference in waveguide mode contribution has potential applications for enhancing the outcoupling of the QLED structure. To fully understand the difference, we have to examine the power dissipation spectra across the whole visible range, as shown in Fig. 6.The four regions in the figure are: 1) Direct emission, 2) Substrate mode, 3) Waveguide mode, and 4) Surface plasmons. The red line represents kair = k0·nair, green ksub = k0·nsub, and white keff = k0·neff. It is obvious that for the QLED in Fig. 6(a), a large portion of the power is dissipated evenly in the waveguide mode and surface plasmons, while for BOLED [Fig. 6(b)] it is obvious that there are two distinct modes in regions 3 and 4, and the surface plasmons are much stronger than the waveguide mode. These mechanisms contribute to the much stronger waveguide mode in the QLED.

 figure: Fig. 6

Fig. 6 Simulated full power dissipation spectra of (a) QLED and (b) BOLED.

Download Full Size | PPT Slide | PDF

4. Optimization of QLED device structure

As explained above, the EQE of QLED is limited by the direct emission part so that it is of vital importance to extract or reduce other optical modes. Currently, a few approaches [36–40] have already been proposed to extract/reduce the other optical modes in an OLED structure. Because of the similarity between QLED and OLED, most of them will also work for QLED, although their contribution or enhancement factor may be different.

To extract substrate mode, the most straightforward approach is to use macroextractors such as hemispheres to circumvent the TIR at the substrate/air interface [40]. The substrates with microstructures such as microspheres and micropyramids can also be used to extract the substrate mode [41]. As explained in [4], for the hemisphere-type macroextractors, all the light trapped in the substrate mode can be outcoupled as the light is at normal incidence when entering the glass hemisphere. Whereas for the case of microstructures, it has been explained in [40] that the aspect ratio and density of the microstructures greatly affect the outcoupling efficiency of the device, and thus it is difficult to outcouple the entire substrate mode. Overall it is safe to say that with the macroextractors, the EQE ceiling of the QLED device has been pushed to a larger portion, with both the light directly emitted and the light previously trapped inside the glass substrate.

As for the waveguide mode, the most straightforward way is to use high refractive index glass substrate, thus the light is trapped inside the substrate instead of the organic and ITO layers [42]. Subsequently, the substrate mode can be extracted further by the macroextractors. We will discuss more about this approach later.

The most difficult mode to extract is the surface plasmons, as it leaks into the metallic electrode as evanescent wave. Thus, the main effort is to reduce the transition to surface plasmons instead of extracting them. The main approach to reduce the surface plasmons is to fine-tune the distance between the emitting layer and the metallic electrode. However, this approach usually comes with increased waveguide mode ratio [43]. At the same time, in OLED stacks the surface plasmons can be suppressed by using oriented emitters [44], while for QLED this is not the case as QDs are isotropic.

Among all these approaches, the most straightforward and economic way to enhance light outcoupling is to optimize the QLED stack by varying the layer thickness. For example, Fig. 7(a) shows the contributions of different optical channels as a function of the BPhen:Cs layer thickness for the BOLED structure with the assumption that q = 0.84 and γ = 0.92. The results agree well with the experimental data reported in [32], which confirms the validity of our simulation model. Similarly, we can use this optimization approach for the QLED stack, Fig. 7(b) shows the corresponding results by varying the thickness of the NPB (HTL) layer, this time a unity intrinsic quantum yield is assumed. From Fig. 7(b), it is obvious that as the NPB layer is between the Al anode and the emitting layer, the variation of NPB layer thickness greatly modifies the OLED cavity, as can be seen from the oscillation of the direct emission part. And it is obvious that the coupling to the surface plasmons is mainly determined by the distance from the emitting layer to the metallic electrode. Thus, increasing the NPB layer thickness greatly reduces the surface plasmons mode. However, the reduced surface plasmons mode mainly transfers to the waveguide mode; the direct emission mode and the substrate mode are still limited by the EQE ceiling. At 75nm, the direct emission reaches the maximum value of 22.8%, while at 95nm direct emission and substrate mode sum up to the maximum of 44.1%. This means that even with outcoupling enhancing structures, at the most only a little less than half of the emitted light can be extracted.

 figure: Fig. 7

Fig. 7 (a) Changing the proportions of different optical channels by tuning the BPhen:Cs layer thickness for the OLED structure, and (b) Changing the proportions of different optical channels by tuning the NPB layer thickness for the QLED structure.

Download Full Size | PPT Slide | PDF

If we vary the ZnO (ETL) layer thickness, the results are a little bit different, as Fig. 8 depicts. This time the cavity effect is much weaker as the thickness between the emitting layer and the metallic electrode is not changed, still it is obvious that only about 40% of the light can be extracted even with outcoupling structures. Without the outcoupling structures, at the most only about 20% of the light can be extracted.

 figure: Fig. 8

Fig. 8 Changing the fraction of power of different optical channels for the QLED structure by varying the ZnO layer thickness.

Download Full Size | PPT Slide | PDF

Of course we can also vary the thickness of the HAT-CN layer, the ITO layer or vary the thickness of two layers simultaneously to optimize the QLED structure, but our tedious optimization of other layer thickness, which is not listed here, indicates that the maximum outcoupling efficiency is still governed by the EQE ceiling. And QLED stack optimization by varying the layer thickness alone is insufficient to dramatically enhance the outcoupling efficiency. Thus, additional approach is required. As mentioned before, generally, it is assumed that with outcoupling structures such as macroextractors, all the direct emission part and the substrate mode can be extracted. The simplest way to enhance the outcoupling of both direct emission and substrate mode is to use a high refractive index glass substrate to reduce or even eliminate the waveguide mode. As demonstrated in Fig. 5, compared to BOLED the QLED structure has more contributions from the waveguide mode. Thus, it is more rewarding to utilize high refractive index glass substrate modes in QLED stack. For example, if we replace the BK7 glass substrate with a glass substrate with n = 1.8, then the ratio of different optical channels is shown in Fig. 9.

 figure: Fig. 9

Fig. 9 Amount of power coupled to different optical channels for the QLED device with a high refractive index (n = 1.8) substrate.

Download Full Size | PPT Slide | PDF

As expected, the direct emission part and substrate mode together now accounts for 62.8%, and the waveguide mode is reduced to 4.3%. If the refractive index of the glass substrate is further increased, the waveguiding effect can be fully eliminated. Table 1 summarizes the fraction of power coupled to different modes for the QLED stack with substrate having different refractive indices. From Table 1, as the refractive index of the substrate increases, the waveguide mode can be fully suppressed. However, after the waveguide mode is suppressed, further increasing the substrate refractive index does not help much about extracting more direct emission part and substrate mode, because the absorption from the multilayer structure becomes more severe. For different substrate refractive index, we can optimize the structure by tuning the layer thickness. Figure 10 shows the maximum fraction of power for both direct emission part and substrate mode we can get by tuning the HTL layer thickness (up to 260nm) under different substrate refractive indices. As Fig. 10 shows, it increases with the substrate refractive index and then saturates. Considering the high cost of high refractive index glasses, the optimal refractive index of glass should be around 2.0. From Fig. 10, we can see that at the most we can extract ~80% of the total emitted power by using high refractive index substrate and outcoupling structures. That is about 2X improvement compared to the structures with BK7 glass if we count both direct emission part and substrate mode. As surface plasmons mode is also greatly reduced when we use high refractive index substrate, the bottleneck comes from the absorption of the QLED structure, which is attributed to the high reflectivity of the substrate.

Tables Icon

Table 1. Fractions of power coupled to different modes for the QLED stack with substrates having different refractive indices.

 figure: Fig. 10

Fig. 10 How the refractive index of the substrate affects different optical channel power proportion.

Download Full Size | PPT Slide | PDF

To fully understand the power redistribution because of the high refractive index substrate, we examine the power dissipation spectra of the QLED with different substrate refractive index [Fig. 11]. From Figs. 11(b)-11(d), as nsub is larger than neff, waveguide mode vanishes.

 figure: Fig. 11

Fig. 11 Full power dissipation spectra of the QLED with different substrate refractive indices: a) nsub = 1.8 b) nsub = 2.0 c) nsub = 2.2 d) nsub = 2.4.

Download Full Size | PPT Slide | PDF

This is indicated by the white line representing keff = k0·neff, which is smaller than the green line representing ksub = k0·nsub, illustrating that the waveguide mode has vanished entirely and transferred to substrate mode and surface plasmons. With Fig. 11 we are also able to explain why surface plasmons first increase a little bit and then decrease dramatically. As nsub increases, the waveguide mode is transferred to the substrate mode. At first as nsub is still not large enough, there is still much portion of the energy left in the surface plasmons, the factors add up to the increased surface plasmons, however, with the continuing increase of nsub, more and more energy is transferred to substrate mode, and when nsub > neff, the conditions for surface plasmons are modified to kx>k0·nsub, which accounts for smaller part of the total dissipated power as indicated by the green lines in Fig. 11.

5. Analyzing the light emission pattern

Besides outcoupling efficiency, light emission pattern is also important for display and lighting applications. Using the dipole model, it is also possible to calculate the light emission pattern of the QLED and the OLED structures shown in Fig. 1(a) and Fig. 2(a), respectively. The simulated results are shown in Fig. 12. It is evident that the light emission spectrum of the QLED structure (~30nm) is much narrower than that of the OLED structure (~80nm). This means we can get much purer and more saturated color from the QLED structure.

 figure: Fig. 12

Fig. 12 Emission spectra of the (a) QLED stack (b) BOLED stack.

Download Full Size | PPT Slide | PDF

If we compare the EL spectra of the QLED/BOLED with its PL spectra, we can see that the cavity effect will modify the spectra of the inhomogeneously broadened emission spectra of the QD/Organic ensembles. As these two devices are both bottom emitting devices with low reflectivity and relatively high transmittance on the bottom side, such modification is not very noticeable for the two devices, especially for the QLED device as its PL spectra is already very narrow. This effect will also modify the emission spectra for Green QLED and Red QLED, and will be different for them because of the intrinsically inhomogeneously broadened spectra.

Generally speaking, QLED has narrower emission linewidth than OLED; therefore, QLED should have much smaller color shift at oblique angles than OLED. This is indeed confirmed by the Δu’v’ diagram plotted in Fig. 13.Our red QLED has a Δu’v’ less than 0.002, which is much smaller than that of a film-compensated multi-domain vertical-alignment LCD panel [45], whose Δu’v’ is 0.005 for the same color. The main reason for this smaller color shift is that QLED does not have birefringence as liquid crystals do [46]. As for the OLED structure, the color shift of the red color is ~0.01, which is comparable with commercial OLED products [47, 48], but is still much higher than QLED. The main reason behind the color shift difference is the intrinsic narrow spectra of QLED. This has been double confirmed by the LCD with QD backlight, which also has smaller color shift than LCD with white LED backlight [13]. As for the green and blue colors, we expect that green and blue QLEDs will also have negligible color shift because of their intrinsic narrow spectra. Thus, QLED displays have great potential to overcome the color shift problem.

 figure: Fig. 13

Fig. 13 Calculated color shift of the proposed red QLED and the red OLED.

Download Full Size | PPT Slide | PDF

We also compare the angular emission pattern of our proposed QLED with OLED. Results are shown in Fig. 14.From Fig. 14, the angular emission pattern of our QLED is a little bit closer to the Lambertian light source.

 figure: Fig. 14

Fig. 14 Simulated angular radiation pattern of the OLED and the QLED structures.

Download Full Size | PPT Slide | PDF

6. Conclusion

We have analyzed the factors affecting the outcoupling of a QLED structure and discussed methods for improving its outcoupling efficiency. By using a high refractive index substrate and optimizing the outcoupling structures, it is possible to enhance the outcoupling efficiency to ~80%. Meanwhile, we have also analyzed the light emitting spectra, color shift, and angular radiation pattern of the QLED structures. Because of its intrinsic narrow emission spectra, QLED structure shows a much weaker color shift as compared to the contemporary OLED structure.

Acknowledgments

The authors are indebted to Prof. Jin Jang from Kyung Hee University for helpful information and thoughtful discussion, Dr. Bert Scholz from Universität Augsburg for helping us with the dipole model, and Dr. Qi Hong and Prof. Yajie Dong of University of Central Florida for the insightful discussion.

References and links

1. B. Geffroy, P. le Roy, and C. Prat, “Organic light-emitting diode (OLED) technology: materials, devices and display technologies,” Polym. Int. 55(6), 572–582 (2006). [CrossRef]  

2. C.-H. Hsiao, Y.-H. Lan, P.-Y. Lee, T.-L. Chiu, and J.-H. Lee, “White organic light-emitting devices with ultra-high color stability over wide luminance range,” Org. Electron. 12(3), 547–555 (2011). [CrossRef]  

3. S. Chung, J.-H. Lee, J. Jeong, J.-J. Kim, and Y. Hong, “Substrate thermal conductivity effect on heat dissipation and lifetime improvement of organic light-emitting diodes,” Appl. Phys. Lett. 94(25), 253302 (2009). [CrossRef]  

4. S. Reineke, M. Thomschke, B. Lüssem, and K. Leo, “White organic light-emitting diodes: status and perspective,” Rev. Mod. Phys. 85(3), 1245–1293 (2013). [CrossRef]  

5. C.-H. Chang, H.-C. Cheng, Y.-J. Lu, K.-C. Tien, H.-W. Lin, C.-L. Lin, C.-J. Yang, and C.-C. Wu, “Enhancing color gamut of white OLED displays by using microcavity green pixels,” Org. Electron. 11(2), 247–254 (2010). [CrossRef]  

6. A. Castan, H.-M. Kim, and J. Jang, “All-solution-processed inverted quantum-dot light-emitting diodes,” ACS Appl. Mater. Interfaces 6(4), 2508–2515 (2014). [CrossRef]   [PubMed]  

7. K.-S. Cho, E. K. Lee, W.-J. Joo, E. Jang, T.-H. Kim, S. J. Lee, S.-J. Kwon, J. Y. Han, B.-K. Kim, B. L. Choi, and J. M. Kim, “High-performance crosslinked colloidal quantum-dot light-emitting diodes,” Nat. Photonics 3(6), 341–345 (2009). [CrossRef]  

8. V. Bulović, A. Shoustikov, M. A. Baldo, E. Bose, V. G. Kozlov, M. E. Thompson, and S. R. Forrest, “Bright, saturated, red-to-yellow organic light-emitting devices based on polarization-induced spectral shifts,” Chem. Phys. Lett. 287(3–4), 455–460 (1998). [CrossRef]  

9. L. Qian, Y. Zheng, J. Xue, and P. H. Holloway, “Stable and efficient quantum-dot light-emitting diodes based on solution-processed multilayer structures,” Nat. Photonics 5(9), 543–548 (2011). [CrossRef]  

10. B. Guzelturk, P. L. H. Martinez, Q. Zhang, Q. Xiong, H. Sun, X. W. Sun, A. O. Govorov, and H. V. Demir, “Excitonics of semiconductor quantum dots and wires for lighting and displays,” Laser Photonics Rev. 8(1), 73–93 (2014). [CrossRef]  

11. Y. Wang, V. D. Ta, Y. Gao, T. C. He, R. Chen, E. Mutlugun, H. V. Demir, and H. D. Sun, “Stimulated emission and lasing from CdSe/CdS/ZnS core-multi-shell quantum dots by simultaneous three-photon absorption,” Adv. Mater. 26(18), 2954–2961 (2014). [CrossRef]   [PubMed]  

12. X. Yang, E. Mutlugun, C. Dang, K. Dev, Y. Gao, S. T. Tan, X. W. Sun, and H. V. Demir, “Highly flexible, electrically driven, top-emitting, quantum dot light-emitting stickers,” ACS Nano 8(8), 8224–8231 (2014). [CrossRef]   [PubMed]  

13. Z. Luo, D. Xu, and S.-T. Wu, “Emerging quantum-dots-enhanced LCDs,” J. Display Technol. 10(7), 526–539 (2014). [CrossRef]  

14. G. J. Supran, Y. Shirasaki, K. W. Song, J.-M. Caruge, P. T. Kazlas, S. Coe-Sullivan, T. L. Andrew, M. G. Bawendi, and V. Bulović, “QLEDs for displays and solid-state lighting,” MRS Bull. 38(09), 703–711 (2013). [CrossRef]  

15. Z. Luo, Y. Chen, and S.-T. Wu, “Wide color gamut LCD with a quantum dot backlight,” Opt. Express 21(22), 26269–26284 (2013). [CrossRef]   [PubMed]  

16. J. F. Van Derlofske, J. M. Hillis, A. Lathrop, J. Wheatley, J. Thielen, and G. Benoit, “Illuminating the value of larger color gamuts for quantum dot displays,” SID Symp. Dig. Tech. Pap. 45(1), 237–240 (2014).

17. M. Sessolo and H. J. Bolink, “Hybrid organic-inorganic light-emitting diodes,” Adv. Mater. 23(16), 1829–1845 (2011). [CrossRef]   [PubMed]  

18. H.-M. Kim, A. R. Mohd Yusoff, T.-W. Kim, Y.-G. Seol, H.-P. Kim, and J. Jang, “Semi-transparent quantum-dot light emitting diodes with an inverted structure,” J. Mater. Chem. C 2(12), 2259–2265 (2014). [CrossRef]  

19. B. S. Mashford, M. Stevenson, Z. Popovic, C. Hamilton, Z. Zhou, C. Breen, J. Steckel, V. Bulovic, M. Bawendi, S. Coe-Sullivan, and P. T. Kazlas, “High-efficiency quantum-dot light-emitting devices with enhanced charge injection,” Nat. Photonics 7(5), 407–412 (2013). [CrossRef]  

20. W. Brütting, J. Frischeisen, T. D. Schmidt, B. J. Scholz, and C. Mayr, “Device efficiency of organic light-emitting diodes: progress by improved light outcoupling,” Phys. Status Solidi A 210(1), 44–65 (2013). [CrossRef]  

21. R. Windisch, P. Heremans, A. Knobloch, P. Kiesel, G. H. Döhler, B. Dutta, and G. Borghs, “Light-emitting diodes with 31% external quantum efficiency by outcoupling of lateral waveguide modes,” Appl. Phys. Lett. 74(16), 2256–2258 (1999). [CrossRef]  

22. K. A. Neyts, “Simulation of light emission from thin-film microcavities,” J. Opt. Soc. Am. A 15(4), 962–971 (1998). [CrossRef]  

23. J. A. E. Wasey and W. L. Barnes, “Efficiency of spontaneous emission from planar microcavities,” J. Mod. Opt. 47(4), 725–741 (2000). [CrossRef]  

24. D. V. Talapin, J.-S. Lee, M. V. Kovalenko, and E. V. Shevchenko, “Prospects of colloidal nanocrystals for electronic and optoelectronic applications,” Chem. Rev. 110(1), 389–458 (2010). [CrossRef]   [PubMed]  

25. W. K. Bae, S. Brovelli, and V. I. Klimov, “Spectroscopic insights into the performance of quantum dot light-emitting diodes,” MRS Bull. 38(09), 721–730 (2013). [CrossRef]  

26. W. K. Bae, Y.-S. Park, J. Lim, D. Lee, L. A. Padilha, H. McDaniel, I. Robel, C. Lee, J. M. Pietryga, and V. I. Klimov, “Controlling the influence of Auger recombination on the performance of quantum-dot light-emitting diodes,” Nat Commun 4, 2661 (2013). [CrossRef]   [PubMed]  

27. M. K. Leung, W.-H. Yang, C.-N. Chuang, J.-H. Lee, C.-F. Lin, M.-K. Wei, and Y.-H. Liu, “1,3,4-Oxadiazole containing silanes as novel hosts for blue phosphorescent organic light emitting diodes,” Org. Lett. 14(19), 4986–4989 (2012). [CrossRef]   [PubMed]  

28. S. Hofmann, M. Thomschke, B. Lüssem, and K. Leo, “Top-emitting organic light-emitting diodes,” Opt. Express 19(106), A1250–A1264 (2011). [CrossRef]   [PubMed]  

29. H. P. Yoon, Y. Lee, C. D. Bohn, S.-H. Ko, A. G. Gianfrancesco, J. S. Steckel, S. Coe-Sullivan, A. A. Talin, and N. B. Zhitenev, “High-resolution photocurrent microscopy using near-field cathodoluminescence of quantum dots,” AIP Adv. 3(6), 062112 (2013). [CrossRef]  

30. E. D. Palik, Handbook of Optical Constants of Solids (Academic, 1985).

31. S. Nowy, B. C. Krummacher, J. Frischeisen, N. A. Reinke, and W. Brütting, “Light extraction and optical loss mechanisms in organic light-emitting diodes: Influence of the emitter quantum efficiency,” J. Appl. Phys. 104(12), 123109 (2008). [CrossRef]  

32. R. Meerheim, M. Furno, S. Hofmann, B. Lüssem, and K. Leo, “Quantification of energy loss mechanisms in organic light-emitting diodes,” Appl. Phys. Lett. 97(25), 253305 (2010). [CrossRef]  

33. D. Poitras, C.-C. Kuo, and C. Py, “Design of high-contrast OLEDs with microcavity effect,” Opt. Express 16(11), 8003–8015 (2008). [CrossRef]   [PubMed]  

34. J.-H. Lee, K.-Y. Chen, C.-C. Hsiao, H.-C. Chen, C.-H. Chang, Y.-W. Kiang, and C. C. Yang, “Radiation simulations of top-emitting organic light-emitting devices with two- and three-microcavity structures,” J. Display Technol. 2(2), 130–137 (2006). [CrossRef]  

35. P. Yeh, Optical Waves in Layered Media (Wiley, 1988).

36. J. Zhao, J. A. Bardecker, A. M. Munro, M. S. Liu, Y. Niu, I. K. Ding, J. Luo, B. Chen, A. K. Y. Jen, and D. S. Ginger, “Efficient CdSe/CdS quantum dot light-emitting diodes using a thermally polymerized hole transport layer,” Nano Lett. 6(3), 463–467 (2006). [CrossRef]   [PubMed]  

37. T. Tsutsui, “Progress in electroluminescent devices using molecular thin films,” MRS Bull. 22(06), 39–45 (1997). [CrossRef]  

38. S. E. Braslavsky, “Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006),” Pure Appl. Chem. 79(3), 293–465 (2007).

39. O. Chen, H. Wei, A. Maurice, M. Bawendi, and P. Reiss, “Pure colors from core–shell quantum dots,” MRS Bull. 38(09), 696–702 (2013). [CrossRef]  

40. G. Horst, “Light extraction from organic light emitting diode substrates: simulation and experiment,” Jpn. J. Appl. Phys. 46(7A7R), 4125–4137 (2007). [CrossRef]  

41. K.-Y. Chen, J.-H. Lee, M.-K. Wei, Y.-T. Chang, Y.-H. Ho, J.-R. Lin, and H. Y. Lin, “Device-dependent angular luminance enhancement and optical responses of organic light-emitting devices with a microlens-array film,” J. Soc. Inf. Disp. 19(1), 21–28 (2011). [CrossRef]  

42. S. Mladenovski, K. Neyts, D. Pavicic, A. Werner, and C. Rothe, “Exceptionally efficient organic light emitting devices using high refractive index substrates,” Opt. Express 17(9), 7562–7570 (2009). [CrossRef]   [PubMed]  

43. C.-L. Lin, T.-Y. Cho, C.-H. Chang, and C.-C. Wu, “Enhancing light outcoupling of organic light-emitting devices by locating emitters around the second antinode of the reflective metal electrode,” Appl. Phys. Lett. 88(8), 081114 (2006). [CrossRef]  

44. J. Frischeisen, D. Yokoyama, A. Endo, C. Adachi, and W. Brütting, “Increased light outcoupling efficiency in dye-doped small molecule organic light-emitting diodes with horizontally oriented emitters,” Org. Electron. 12(5), 809–817 (2011). [CrossRef]  

45. P. Seong-Sik, S. Insung, C. Eunyoung, P. Seungwon, and K. Euisoo, “Color shift reduction of liquid crystal displays by controlling light distribution using a micro-Lens array film,” J. Display Technol. 8(11), 643–649 (2012). [CrossRef]  

46. R. Lu, Q. Hong, Z. Ge, and S.-T. Wu, “Color shift reduction of a multi-domain IPS-LCD using RGB-LED backlight,” Opt. Express 14(13), 6243–6252 (2006). [CrossRef]   [PubMed]  

47. C.-H. Oh, H.-J. Shin, W.-J. Nam, B.-C. Ahn, S.-Y. Cha, and S.-D. Yeo, “Technological progress and commercialization of OLED TV,” SID Symp. Dig. Tech. Pap. 44(1), 239–242 (2013).

48. C.-W. Han, K.-M. Kim, S.-J. Bae, H.-S. Choi, J.-M. Lee, T.-S. Kim, Y.-H. Tak, S.-Y. Cha, and B.-C. Ahn, “55-inch FHD OLED TV employing new tandem WOLEDs,” SID Symp. Dig. Tech. Pap. 43(1), 279–281 (2012). [CrossRef]  

References

  • View by:

  1. B. Geffroy, P. le Roy, and C. Prat, “Organic light-emitting diode (OLED) technology: materials, devices and display technologies,” Polym. Int. 55(6), 572–582 (2006).
    [Crossref]
  2. C.-H. Hsiao, Y.-H. Lan, P.-Y. Lee, T.-L. Chiu, and J.-H. Lee, “White organic light-emitting devices with ultra-high color stability over wide luminance range,” Org. Electron. 12(3), 547–555 (2011).
    [Crossref]
  3. S. Chung, J.-H. Lee, J. Jeong, J.-J. Kim, and Y. Hong, “Substrate thermal conductivity effect on heat dissipation and lifetime improvement of organic light-emitting diodes,” Appl. Phys. Lett. 94(25), 253302 (2009).
    [Crossref]
  4. S. Reineke, M. Thomschke, B. Lüssem, and K. Leo, “White organic light-emitting diodes: status and perspective,” Rev. Mod. Phys. 85(3), 1245–1293 (2013).
    [Crossref]
  5. C.-H. Chang, H.-C. Cheng, Y.-J. Lu, K.-C. Tien, H.-W. Lin, C.-L. Lin, C.-J. Yang, and C.-C. Wu, “Enhancing color gamut of white OLED displays by using microcavity green pixels,” Org. Electron. 11(2), 247–254 (2010).
    [Crossref]
  6. A. Castan, H.-M. Kim, and J. Jang, “All-solution-processed inverted quantum-dot light-emitting diodes,” ACS Appl. Mater. Interfaces 6(4), 2508–2515 (2014).
    [Crossref] [PubMed]
  7. K.-S. Cho, E. K. Lee, W.-J. Joo, E. Jang, T.-H. Kim, S. J. Lee, S.-J. Kwon, J. Y. Han, B.-K. Kim, B. L. Choi, and J. M. Kim, “High-performance crosslinked colloidal quantum-dot light-emitting diodes,” Nat. Photonics 3(6), 341–345 (2009).
    [Crossref]
  8. V. Bulović, A. Shoustikov, M. A. Baldo, E. Bose, V. G. Kozlov, M. E. Thompson, and S. R. Forrest, “Bright, saturated, red-to-yellow organic light-emitting devices based on polarization-induced spectral shifts,” Chem. Phys. Lett. 287(3–4), 455–460 (1998).
    [Crossref]
  9. L. Qian, Y. Zheng, J. Xue, and P. H. Holloway, “Stable and efficient quantum-dot light-emitting diodes based on solution-processed multilayer structures,” Nat. Photonics 5(9), 543–548 (2011).
    [Crossref]
  10. B. Guzelturk, P. L. H. Martinez, Q. Zhang, Q. Xiong, H. Sun, X. W. Sun, A. O. Govorov, and H. V. Demir, “Excitonics of semiconductor quantum dots and wires for lighting and displays,” Laser Photonics Rev. 8(1), 73–93 (2014).
    [Crossref]
  11. Y. Wang, V. D. Ta, Y. Gao, T. C. He, R. Chen, E. Mutlugun, H. V. Demir, and H. D. Sun, “Stimulated emission and lasing from CdSe/CdS/ZnS core-multi-shell quantum dots by simultaneous three-photon absorption,” Adv. Mater. 26(18), 2954–2961 (2014).
    [Crossref] [PubMed]
  12. X. Yang, E. Mutlugun, C. Dang, K. Dev, Y. Gao, S. T. Tan, X. W. Sun, and H. V. Demir, “Highly flexible, electrically driven, top-emitting, quantum dot light-emitting stickers,” ACS Nano 8(8), 8224–8231 (2014).
    [Crossref] [PubMed]
  13. Z. Luo, D. Xu, and S.-T. Wu, “Emerging quantum-dots-enhanced LCDs,” J. Display Technol. 10(7), 526–539 (2014).
    [Crossref]
  14. G. J. Supran, Y. Shirasaki, K. W. Song, J.-M. Caruge, P. T. Kazlas, S. Coe-Sullivan, T. L. Andrew, M. G. Bawendi, and V. Bulović, “QLEDs for displays and solid-state lighting,” MRS Bull. 38(09), 703–711 (2013).
    [Crossref]
  15. Z. Luo, Y. Chen, and S.-T. Wu, “Wide color gamut LCD with a quantum dot backlight,” Opt. Express 21(22), 26269–26284 (2013).
    [Crossref] [PubMed]
  16. J. F. Van Derlofske, J. M. Hillis, A. Lathrop, J. Wheatley, J. Thielen, and G. Benoit, “Illuminating the value of larger color gamuts for quantum dot displays,” SID Symp. Dig. Tech. Pap. 45(1), 237–240 (2014).
  17. M. Sessolo and H. J. Bolink, “Hybrid organic-inorganic light-emitting diodes,” Adv. Mater. 23(16), 1829–1845 (2011).
    [Crossref] [PubMed]
  18. H.-M. Kim, A. R. Mohd Yusoff, T.-W. Kim, Y.-G. Seol, H.-P. Kim, and J. Jang, “Semi-transparent quantum-dot light emitting diodes with an inverted structure,” J. Mater. Chem. C 2(12), 2259–2265 (2014).
    [Crossref]
  19. B. S. Mashford, M. Stevenson, Z. Popovic, C. Hamilton, Z. Zhou, C. Breen, J. Steckel, V. Bulovic, M. Bawendi, S. Coe-Sullivan, and P. T. Kazlas, “High-efficiency quantum-dot light-emitting devices with enhanced charge injection,” Nat. Photonics 7(5), 407–412 (2013).
    [Crossref]
  20. W. Brütting, J. Frischeisen, T. D. Schmidt, B. J. Scholz, and C. Mayr, “Device efficiency of organic light-emitting diodes: progress by improved light outcoupling,” Phys. Status Solidi A 210(1), 44–65 (2013).
    [Crossref]
  21. R. Windisch, P. Heremans, A. Knobloch, P. Kiesel, G. H. Döhler, B. Dutta, and G. Borghs, “Light-emitting diodes with 31% external quantum efficiency by outcoupling of lateral waveguide modes,” Appl. Phys. Lett. 74(16), 2256–2258 (1999).
    [Crossref]
  22. K. A. Neyts, “Simulation of light emission from thin-film microcavities,” J. Opt. Soc. Am. A 15(4), 962–971 (1998).
    [Crossref]
  23. J. A. E. Wasey and W. L. Barnes, “Efficiency of spontaneous emission from planar microcavities,” J. Mod. Opt. 47(4), 725–741 (2000).
    [Crossref]
  24. D. V. Talapin, J.-S. Lee, M. V. Kovalenko, and E. V. Shevchenko, “Prospects of colloidal nanocrystals for electronic and optoelectronic applications,” Chem. Rev. 110(1), 389–458 (2010).
    [Crossref] [PubMed]
  25. W. K. Bae, S. Brovelli, and V. I. Klimov, “Spectroscopic insights into the performance of quantum dot light-emitting diodes,” MRS Bull. 38(09), 721–730 (2013).
    [Crossref]
  26. W. K. Bae, Y.-S. Park, J. Lim, D. Lee, L. A. Padilha, H. McDaniel, I. Robel, C. Lee, J. M. Pietryga, and V. I. Klimov, “Controlling the influence of Auger recombination on the performance of quantum-dot light-emitting diodes,” Nat Commun 4, 2661 (2013).
    [Crossref] [PubMed]
  27. M. K. Leung, W.-H. Yang, C.-N. Chuang, J.-H. Lee, C.-F. Lin, M.-K. Wei, and Y.-H. Liu, “1,3,4-Oxadiazole containing silanes as novel hosts for blue phosphorescent organic light emitting diodes,” Org. Lett. 14(19), 4986–4989 (2012).
    [Crossref] [PubMed]
  28. S. Hofmann, M. Thomschke, B. Lüssem, and K. Leo, “Top-emitting organic light-emitting diodes,” Opt. Express 19(106), A1250–A1264 (2011).
    [Crossref] [PubMed]
  29. H. P. Yoon, Y. Lee, C. D. Bohn, S.-H. Ko, A. G. Gianfrancesco, J. S. Steckel, S. Coe-Sullivan, A. A. Talin, and N. B. Zhitenev, “High-resolution photocurrent microscopy using near-field cathodoluminescence of quantum dots,” AIP Adv. 3(6), 062112 (2013).
    [Crossref]
  30. E. D. Palik, Handbook of Optical Constants of Solids (Academic, 1985).
  31. S. Nowy, B. C. Krummacher, J. Frischeisen, N. A. Reinke, and W. Brütting, “Light extraction and optical loss mechanisms in organic light-emitting diodes: Influence of the emitter quantum efficiency,” J. Appl. Phys. 104(12), 123109 (2008).
    [Crossref]
  32. R. Meerheim, M. Furno, S. Hofmann, B. Lüssem, and K. Leo, “Quantification of energy loss mechanisms in organic light-emitting diodes,” Appl. Phys. Lett. 97(25), 253305 (2010).
    [Crossref]
  33. D. Poitras, C.-C. Kuo, and C. Py, “Design of high-contrast OLEDs with microcavity effect,” Opt. Express 16(11), 8003–8015 (2008).
    [Crossref] [PubMed]
  34. J.-H. Lee, K.-Y. Chen, C.-C. Hsiao, H.-C. Chen, C.-H. Chang, Y.-W. Kiang, and C. C. Yang, “Radiation simulations of top-emitting organic light-emitting devices with two- and three-microcavity structures,” J. Display Technol. 2(2), 130–137 (2006).
    [Crossref]
  35. P. Yeh, Optical Waves in Layered Media (Wiley, 1988).
  36. J. Zhao, J. A. Bardecker, A. M. Munro, M. S. Liu, Y. Niu, I. K. Ding, J. Luo, B. Chen, A. K. Y. Jen, and D. S. Ginger, “Efficient CdSe/CdS quantum dot light-emitting diodes using a thermally polymerized hole transport layer,” Nano Lett. 6(3), 463–467 (2006).
    [Crossref] [PubMed]
  37. T. Tsutsui, “Progress in electroluminescent devices using molecular thin films,” MRS Bull. 22(06), 39–45 (1997).
    [Crossref]
  38. S. E. Braslavsky, “Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006),” Pure Appl. Chem. 79(3), 293–465 (2007).
  39. O. Chen, H. Wei, A. Maurice, M. Bawendi, and P. Reiss, “Pure colors from core–shell quantum dots,” MRS Bull. 38(09), 696–702 (2013).
    [Crossref]
  40. G. Horst, “Light extraction from organic light emitting diode substrates: simulation and experiment,” Jpn. J. Appl. Phys. 46(7A7R), 4125–4137 (2007).
    [Crossref]
  41. K.-Y. Chen, J.-H. Lee, M.-K. Wei, Y.-T. Chang, Y.-H. Ho, J.-R. Lin, and H. Y. Lin, “Device-dependent angular luminance enhancement and optical responses of organic light-emitting devices with a microlens-array film,” J. Soc. Inf. Disp. 19(1), 21–28 (2011).
    [Crossref]
  42. S. Mladenovski, K. Neyts, D. Pavicic, A. Werner, and C. Rothe, “Exceptionally efficient organic light emitting devices using high refractive index substrates,” Opt. Express 17(9), 7562–7570 (2009).
    [Crossref] [PubMed]
  43. C.-L. Lin, T.-Y. Cho, C.-H. Chang, and C.-C. Wu, “Enhancing light outcoupling of organic light-emitting devices by locating emitters around the second antinode of the reflective metal electrode,” Appl. Phys. Lett. 88(8), 081114 (2006).
    [Crossref]
  44. J. Frischeisen, D. Yokoyama, A. Endo, C. Adachi, and W. Brütting, “Increased light outcoupling efficiency in dye-doped small molecule organic light-emitting diodes with horizontally oriented emitters,” Org. Electron. 12(5), 809–817 (2011).
    [Crossref]
  45. P. Seong-Sik, S. Insung, C. Eunyoung, P. Seungwon, and K. Euisoo, “Color shift reduction of liquid crystal displays by controlling light distribution using a micro-Lens array film,” J. Display Technol. 8(11), 643–649 (2012).
    [Crossref]
  46. R. Lu, Q. Hong, Z. Ge, and S.-T. Wu, “Color shift reduction of a multi-domain IPS-LCD using RGB-LED backlight,” Opt. Express 14(13), 6243–6252 (2006).
    [Crossref] [PubMed]
  47. C.-H. Oh, H.-J. Shin, W.-J. Nam, B.-C. Ahn, S.-Y. Cha, and S.-D. Yeo, “Technological progress and commercialization of OLED TV,” SID Symp. Dig. Tech. Pap. 44(1), 239–242 (2013).
  48. C.-W. Han, K.-M. Kim, S.-J. Bae, H.-S. Choi, J.-M. Lee, T.-S. Kim, Y.-H. Tak, S.-Y. Cha, and B.-C. Ahn, “55-inch FHD OLED TV employing new tandem WOLEDs,” SID Symp. Dig. Tech. Pap. 43(1), 279–281 (2012).
    [Crossref]

2014 (6)

A. Castan, H.-M. Kim, and J. Jang, “All-solution-processed inverted quantum-dot light-emitting diodes,” ACS Appl. Mater. Interfaces 6(4), 2508–2515 (2014).
[Crossref] [PubMed]

B. Guzelturk, P. L. H. Martinez, Q. Zhang, Q. Xiong, H. Sun, X. W. Sun, A. O. Govorov, and H. V. Demir, “Excitonics of semiconductor quantum dots and wires for lighting and displays,” Laser Photonics Rev. 8(1), 73–93 (2014).
[Crossref]

Y. Wang, V. D. Ta, Y. Gao, T. C. He, R. Chen, E. Mutlugun, H. V. Demir, and H. D. Sun, “Stimulated emission and lasing from CdSe/CdS/ZnS core-multi-shell quantum dots by simultaneous three-photon absorption,” Adv. Mater. 26(18), 2954–2961 (2014).
[Crossref] [PubMed]

X. Yang, E. Mutlugun, C. Dang, K. Dev, Y. Gao, S. T. Tan, X. W. Sun, and H. V. Demir, “Highly flexible, electrically driven, top-emitting, quantum dot light-emitting stickers,” ACS Nano 8(8), 8224–8231 (2014).
[Crossref] [PubMed]

Z. Luo, D. Xu, and S.-T. Wu, “Emerging quantum-dots-enhanced LCDs,” J. Display Technol. 10(7), 526–539 (2014).
[Crossref]

H.-M. Kim, A. R. Mohd Yusoff, T.-W. Kim, Y.-G. Seol, H.-P. Kim, and J. Jang, “Semi-transparent quantum-dot light emitting diodes with an inverted structure,” J. Mater. Chem. C 2(12), 2259–2265 (2014).
[Crossref]

2013 (9)

B. S. Mashford, M. Stevenson, Z. Popovic, C. Hamilton, Z. Zhou, C. Breen, J. Steckel, V. Bulovic, M. Bawendi, S. Coe-Sullivan, and P. T. Kazlas, “High-efficiency quantum-dot light-emitting devices with enhanced charge injection,” Nat. Photonics 7(5), 407–412 (2013).
[Crossref]

W. Brütting, J. Frischeisen, T. D. Schmidt, B. J. Scholz, and C. Mayr, “Device efficiency of organic light-emitting diodes: progress by improved light outcoupling,” Phys. Status Solidi A 210(1), 44–65 (2013).
[Crossref]

G. J. Supran, Y. Shirasaki, K. W. Song, J.-M. Caruge, P. T. Kazlas, S. Coe-Sullivan, T. L. Andrew, M. G. Bawendi, and V. Bulović, “QLEDs for displays and solid-state lighting,” MRS Bull. 38(09), 703–711 (2013).
[Crossref]

Z. Luo, Y. Chen, and S.-T. Wu, “Wide color gamut LCD with a quantum dot backlight,” Opt. Express 21(22), 26269–26284 (2013).
[Crossref] [PubMed]

S. Reineke, M. Thomschke, B. Lüssem, and K. Leo, “White organic light-emitting diodes: status and perspective,” Rev. Mod. Phys. 85(3), 1245–1293 (2013).
[Crossref]

W. K. Bae, S. Brovelli, and V. I. Klimov, “Spectroscopic insights into the performance of quantum dot light-emitting diodes,” MRS Bull. 38(09), 721–730 (2013).
[Crossref]

W. K. Bae, Y.-S. Park, J. Lim, D. Lee, L. A. Padilha, H. McDaniel, I. Robel, C. Lee, J. M. Pietryga, and V. I. Klimov, “Controlling the influence of Auger recombination on the performance of quantum-dot light-emitting diodes,” Nat Commun 4, 2661 (2013).
[Crossref] [PubMed]

H. P. Yoon, Y. Lee, C. D. Bohn, S.-H. Ko, A. G. Gianfrancesco, J. S. Steckel, S. Coe-Sullivan, A. A. Talin, and N. B. Zhitenev, “High-resolution photocurrent microscopy using near-field cathodoluminescence of quantum dots,” AIP Adv. 3(6), 062112 (2013).
[Crossref]

O. Chen, H. Wei, A. Maurice, M. Bawendi, and P. Reiss, “Pure colors from core–shell quantum dots,” MRS Bull. 38(09), 696–702 (2013).
[Crossref]

2012 (2)

M. K. Leung, W.-H. Yang, C.-N. Chuang, J.-H. Lee, C.-F. Lin, M.-K. Wei, and Y.-H. Liu, “1,3,4-Oxadiazole containing silanes as novel hosts for blue phosphorescent organic light emitting diodes,” Org. Lett. 14(19), 4986–4989 (2012).
[Crossref] [PubMed]

P. Seong-Sik, S. Insung, C. Eunyoung, P. Seungwon, and K. Euisoo, “Color shift reduction of liquid crystal displays by controlling light distribution using a micro-Lens array film,” J. Display Technol. 8(11), 643–649 (2012).
[Crossref]

2011 (6)

J. Frischeisen, D. Yokoyama, A. Endo, C. Adachi, and W. Brütting, “Increased light outcoupling efficiency in dye-doped small molecule organic light-emitting diodes with horizontally oriented emitters,” Org. Electron. 12(5), 809–817 (2011).
[Crossref]

S. Hofmann, M. Thomschke, B. Lüssem, and K. Leo, “Top-emitting organic light-emitting diodes,” Opt. Express 19(106), A1250–A1264 (2011).
[Crossref] [PubMed]

K.-Y. Chen, J.-H. Lee, M.-K. Wei, Y.-T. Chang, Y.-H. Ho, J.-R. Lin, and H. Y. Lin, “Device-dependent angular luminance enhancement and optical responses of organic light-emitting devices with a microlens-array film,” J. Soc. Inf. Disp. 19(1), 21–28 (2011).
[Crossref]

C.-H. Hsiao, Y.-H. Lan, P.-Y. Lee, T.-L. Chiu, and J.-H. Lee, “White organic light-emitting devices with ultra-high color stability over wide luminance range,” Org. Electron. 12(3), 547–555 (2011).
[Crossref]

L. Qian, Y. Zheng, J. Xue, and P. H. Holloway, “Stable and efficient quantum-dot light-emitting diodes based on solution-processed multilayer structures,” Nat. Photonics 5(9), 543–548 (2011).
[Crossref]

M. Sessolo and H. J. Bolink, “Hybrid organic-inorganic light-emitting diodes,” Adv. Mater. 23(16), 1829–1845 (2011).
[Crossref] [PubMed]

2010 (3)

C.-H. Chang, H.-C. Cheng, Y.-J. Lu, K.-C. Tien, H.-W. Lin, C.-L. Lin, C.-J. Yang, and C.-C. Wu, “Enhancing color gamut of white OLED displays by using microcavity green pixels,” Org. Electron. 11(2), 247–254 (2010).
[Crossref]

R. Meerheim, M. Furno, S. Hofmann, B. Lüssem, and K. Leo, “Quantification of energy loss mechanisms in organic light-emitting diodes,” Appl. Phys. Lett. 97(25), 253305 (2010).
[Crossref]

D. V. Talapin, J.-S. Lee, M. V. Kovalenko, and E. V. Shevchenko, “Prospects of colloidal nanocrystals for electronic and optoelectronic applications,” Chem. Rev. 110(1), 389–458 (2010).
[Crossref] [PubMed]

2009 (3)

S. Mladenovski, K. Neyts, D. Pavicic, A. Werner, and C. Rothe, “Exceptionally efficient organic light emitting devices using high refractive index substrates,” Opt. Express 17(9), 7562–7570 (2009).
[Crossref] [PubMed]

S. Chung, J.-H. Lee, J. Jeong, J.-J. Kim, and Y. Hong, “Substrate thermal conductivity effect on heat dissipation and lifetime improvement of organic light-emitting diodes,” Appl. Phys. Lett. 94(25), 253302 (2009).
[Crossref]

K.-S. Cho, E. K. Lee, W.-J. Joo, E. Jang, T.-H. Kim, S. J. Lee, S.-J. Kwon, J. Y. Han, B.-K. Kim, B. L. Choi, and J. M. Kim, “High-performance crosslinked colloidal quantum-dot light-emitting diodes,” Nat. Photonics 3(6), 341–345 (2009).
[Crossref]

2008 (2)

D. Poitras, C.-C. Kuo, and C. Py, “Design of high-contrast OLEDs with microcavity effect,” Opt. Express 16(11), 8003–8015 (2008).
[Crossref] [PubMed]

S. Nowy, B. C. Krummacher, J. Frischeisen, N. A. Reinke, and W. Brütting, “Light extraction and optical loss mechanisms in organic light-emitting diodes: Influence of the emitter quantum efficiency,” J. Appl. Phys. 104(12), 123109 (2008).
[Crossref]

2007 (1)

G. Horst, “Light extraction from organic light emitting diode substrates: simulation and experiment,” Jpn. J. Appl. Phys. 46(7A7R), 4125–4137 (2007).
[Crossref]

2006 (5)

C.-L. Lin, T.-Y. Cho, C.-H. Chang, and C.-C. Wu, “Enhancing light outcoupling of organic light-emitting devices by locating emitters around the second antinode of the reflective metal electrode,” Appl. Phys. Lett. 88(8), 081114 (2006).
[Crossref]

J.-H. Lee, K.-Y. Chen, C.-C. Hsiao, H.-C. Chen, C.-H. Chang, Y.-W. Kiang, and C. C. Yang, “Radiation simulations of top-emitting organic light-emitting devices with two- and three-microcavity structures,” J. Display Technol. 2(2), 130–137 (2006).
[Crossref]

J. Zhao, J. A. Bardecker, A. M. Munro, M. S. Liu, Y. Niu, I. K. Ding, J. Luo, B. Chen, A. K. Y. Jen, and D. S. Ginger, “Efficient CdSe/CdS quantum dot light-emitting diodes using a thermally polymerized hole transport layer,” Nano Lett. 6(3), 463–467 (2006).
[Crossref] [PubMed]

B. Geffroy, P. le Roy, and C. Prat, “Organic light-emitting diode (OLED) technology: materials, devices and display technologies,” Polym. Int. 55(6), 572–582 (2006).
[Crossref]

R. Lu, Q. Hong, Z. Ge, and S.-T. Wu, “Color shift reduction of a multi-domain IPS-LCD using RGB-LED backlight,” Opt. Express 14(13), 6243–6252 (2006).
[Crossref] [PubMed]

2000 (1)

J. A. E. Wasey and W. L. Barnes, “Efficiency of spontaneous emission from planar microcavities,” J. Mod. Opt. 47(4), 725–741 (2000).
[Crossref]

1999 (1)

R. Windisch, P. Heremans, A. Knobloch, P. Kiesel, G. H. Döhler, B. Dutta, and G. Borghs, “Light-emitting diodes with 31% external quantum efficiency by outcoupling of lateral waveguide modes,” Appl. Phys. Lett. 74(16), 2256–2258 (1999).
[Crossref]

1998 (2)

K. A. Neyts, “Simulation of light emission from thin-film microcavities,” J. Opt. Soc. Am. A 15(4), 962–971 (1998).
[Crossref]

V. Bulović, A. Shoustikov, M. A. Baldo, E. Bose, V. G. Kozlov, M. E. Thompson, and S. R. Forrest, “Bright, saturated, red-to-yellow organic light-emitting devices based on polarization-induced spectral shifts,” Chem. Phys. Lett. 287(3–4), 455–460 (1998).
[Crossref]

1997 (1)

T. Tsutsui, “Progress in electroluminescent devices using molecular thin films,” MRS Bull. 22(06), 39–45 (1997).
[Crossref]

Adachi, C.

J. Frischeisen, D. Yokoyama, A. Endo, C. Adachi, and W. Brütting, “Increased light outcoupling efficiency in dye-doped small molecule organic light-emitting diodes with horizontally oriented emitters,” Org. Electron. 12(5), 809–817 (2011).
[Crossref]

Andrew, T. L.

G. J. Supran, Y. Shirasaki, K. W. Song, J.-M. Caruge, P. T. Kazlas, S. Coe-Sullivan, T. L. Andrew, M. G. Bawendi, and V. Bulović, “QLEDs for displays and solid-state lighting,” MRS Bull. 38(09), 703–711 (2013).
[Crossref]

Bae, W. K.

W. K. Bae, S. Brovelli, and V. I. Klimov, “Spectroscopic insights into the performance of quantum dot light-emitting diodes,” MRS Bull. 38(09), 721–730 (2013).
[Crossref]

W. K. Bae, Y.-S. Park, J. Lim, D. Lee, L. A. Padilha, H. McDaniel, I. Robel, C. Lee, J. M. Pietryga, and V. I. Klimov, “Controlling the influence of Auger recombination on the performance of quantum-dot light-emitting diodes,” Nat Commun 4, 2661 (2013).
[Crossref] [PubMed]

Baldo, M. A.

V. Bulović, A. Shoustikov, M. A. Baldo, E. Bose, V. G. Kozlov, M. E. Thompson, and S. R. Forrest, “Bright, saturated, red-to-yellow organic light-emitting devices based on polarization-induced spectral shifts,” Chem. Phys. Lett. 287(3–4), 455–460 (1998).
[Crossref]

Bardecker, J. A.

J. Zhao, J. A. Bardecker, A. M. Munro, M. S. Liu, Y. Niu, I. K. Ding, J. Luo, B. Chen, A. K. Y. Jen, and D. S. Ginger, “Efficient CdSe/CdS quantum dot light-emitting diodes using a thermally polymerized hole transport layer,” Nano Lett. 6(3), 463–467 (2006).
[Crossref] [PubMed]

Barnes, W. L.

J. A. E. Wasey and W. L. Barnes, “Efficiency of spontaneous emission from planar microcavities,” J. Mod. Opt. 47(4), 725–741 (2000).
[Crossref]

Bawendi, M.

B. S. Mashford, M. Stevenson, Z. Popovic, C. Hamilton, Z. Zhou, C. Breen, J. Steckel, V. Bulovic, M. Bawendi, S. Coe-Sullivan, and P. T. Kazlas, “High-efficiency quantum-dot light-emitting devices with enhanced charge injection,” Nat. Photonics 7(5), 407–412 (2013).
[Crossref]

O. Chen, H. Wei, A. Maurice, M. Bawendi, and P. Reiss, “Pure colors from core–shell quantum dots,” MRS Bull. 38(09), 696–702 (2013).
[Crossref]

Bawendi, M. G.

G. J. Supran, Y. Shirasaki, K. W. Song, J.-M. Caruge, P. T. Kazlas, S. Coe-Sullivan, T. L. Andrew, M. G. Bawendi, and V. Bulović, “QLEDs for displays and solid-state lighting,” MRS Bull. 38(09), 703–711 (2013).
[Crossref]

Bohn, C. D.

H. P. Yoon, Y. Lee, C. D. Bohn, S.-H. Ko, A. G. Gianfrancesco, J. S. Steckel, S. Coe-Sullivan, A. A. Talin, and N. B. Zhitenev, “High-resolution photocurrent microscopy using near-field cathodoluminescence of quantum dots,” AIP Adv. 3(6), 062112 (2013).
[Crossref]

Bolink, H. J.

M. Sessolo and H. J. Bolink, “Hybrid organic-inorganic light-emitting diodes,” Adv. Mater. 23(16), 1829–1845 (2011).
[Crossref] [PubMed]

Borghs, G.

R. Windisch, P. Heremans, A. Knobloch, P. Kiesel, G. H. Döhler, B. Dutta, and G. Borghs, “Light-emitting diodes with 31% external quantum efficiency by outcoupling of lateral waveguide modes,” Appl. Phys. Lett. 74(16), 2256–2258 (1999).
[Crossref]

Bose, E.

V. Bulović, A. Shoustikov, M. A. Baldo, E. Bose, V. G. Kozlov, M. E. Thompson, and S. R. Forrest, “Bright, saturated, red-to-yellow organic light-emitting devices based on polarization-induced spectral shifts,” Chem. Phys. Lett. 287(3–4), 455–460 (1998).
[Crossref]

Breen, C.

B. S. Mashford, M. Stevenson, Z. Popovic, C. Hamilton, Z. Zhou, C. Breen, J. Steckel, V. Bulovic, M. Bawendi, S. Coe-Sullivan, and P. T. Kazlas, “High-efficiency quantum-dot light-emitting devices with enhanced charge injection,” Nat. Photonics 7(5), 407–412 (2013).
[Crossref]

Brovelli, S.

W. K. Bae, S. Brovelli, and V. I. Klimov, “Spectroscopic insights into the performance of quantum dot light-emitting diodes,” MRS Bull. 38(09), 721–730 (2013).
[Crossref]

Brütting, W.

W. Brütting, J. Frischeisen, T. D. Schmidt, B. J. Scholz, and C. Mayr, “Device efficiency of organic light-emitting diodes: progress by improved light outcoupling,” Phys. Status Solidi A 210(1), 44–65 (2013).
[Crossref]

J. Frischeisen, D. Yokoyama, A. Endo, C. Adachi, and W. Brütting, “Increased light outcoupling efficiency in dye-doped small molecule organic light-emitting diodes with horizontally oriented emitters,” Org. Electron. 12(5), 809–817 (2011).
[Crossref]

S. Nowy, B. C. Krummacher, J. Frischeisen, N. A. Reinke, and W. Brütting, “Light extraction and optical loss mechanisms in organic light-emitting diodes: Influence of the emitter quantum efficiency,” J. Appl. Phys. 104(12), 123109 (2008).
[Crossref]

Bulovic, V.

B. S. Mashford, M. Stevenson, Z. Popovic, C. Hamilton, Z. Zhou, C. Breen, J. Steckel, V. Bulovic, M. Bawendi, S. Coe-Sullivan, and P. T. Kazlas, “High-efficiency quantum-dot light-emitting devices with enhanced charge injection,” Nat. Photonics 7(5), 407–412 (2013).
[Crossref]

G. J. Supran, Y. Shirasaki, K. W. Song, J.-M. Caruge, P. T. Kazlas, S. Coe-Sullivan, T. L. Andrew, M. G. Bawendi, and V. Bulović, “QLEDs for displays and solid-state lighting,” MRS Bull. 38(09), 703–711 (2013).
[Crossref]

V. Bulović, A. Shoustikov, M. A. Baldo, E. Bose, V. G. Kozlov, M. E. Thompson, and S. R. Forrest, “Bright, saturated, red-to-yellow organic light-emitting devices based on polarization-induced spectral shifts,” Chem. Phys. Lett. 287(3–4), 455–460 (1998).
[Crossref]

Caruge, J.-M.

G. J. Supran, Y. Shirasaki, K. W. Song, J.-M. Caruge, P. T. Kazlas, S. Coe-Sullivan, T. L. Andrew, M. G. Bawendi, and V. Bulović, “QLEDs for displays and solid-state lighting,” MRS Bull. 38(09), 703–711 (2013).
[Crossref]

Castan, A.

A. Castan, H.-M. Kim, and J. Jang, “All-solution-processed inverted quantum-dot light-emitting diodes,” ACS Appl. Mater. Interfaces 6(4), 2508–2515 (2014).
[Crossref] [PubMed]

Chang, C.-H.

C.-H. Chang, H.-C. Cheng, Y.-J. Lu, K.-C. Tien, H.-W. Lin, C.-L. Lin, C.-J. Yang, and C.-C. Wu, “Enhancing color gamut of white OLED displays by using microcavity green pixels,” Org. Electron. 11(2), 247–254 (2010).
[Crossref]

J.-H. Lee, K.-Y. Chen, C.-C. Hsiao, H.-C. Chen, C.-H. Chang, Y.-W. Kiang, and C. C. Yang, “Radiation simulations of top-emitting organic light-emitting devices with two- and three-microcavity structures,” J. Display Technol. 2(2), 130–137 (2006).
[Crossref]

C.-L. Lin, T.-Y. Cho, C.-H. Chang, and C.-C. Wu, “Enhancing light outcoupling of organic light-emitting devices by locating emitters around the second antinode of the reflective metal electrode,” Appl. Phys. Lett. 88(8), 081114 (2006).
[Crossref]

Chang, Y.-T.

K.-Y. Chen, J.-H. Lee, M.-K. Wei, Y.-T. Chang, Y.-H. Ho, J.-R. Lin, and H. Y. Lin, “Device-dependent angular luminance enhancement and optical responses of organic light-emitting devices with a microlens-array film,” J. Soc. Inf. Disp. 19(1), 21–28 (2011).
[Crossref]

Chen, B.

J. Zhao, J. A. Bardecker, A. M. Munro, M. S. Liu, Y. Niu, I. K. Ding, J. Luo, B. Chen, A. K. Y. Jen, and D. S. Ginger, “Efficient CdSe/CdS quantum dot light-emitting diodes using a thermally polymerized hole transport layer,” Nano Lett. 6(3), 463–467 (2006).
[Crossref] [PubMed]

Chen, H.-C.

Chen, K.-Y.

K.-Y. Chen, J.-H. Lee, M.-K. Wei, Y.-T. Chang, Y.-H. Ho, J.-R. Lin, and H. Y. Lin, “Device-dependent angular luminance enhancement and optical responses of organic light-emitting devices with a microlens-array film,” J. Soc. Inf. Disp. 19(1), 21–28 (2011).
[Crossref]

J.-H. Lee, K.-Y. Chen, C.-C. Hsiao, H.-C. Chen, C.-H. Chang, Y.-W. Kiang, and C. C. Yang, “Radiation simulations of top-emitting organic light-emitting devices with two- and three-microcavity structures,” J. Display Technol. 2(2), 130–137 (2006).
[Crossref]

Chen, O.

O. Chen, H. Wei, A. Maurice, M. Bawendi, and P. Reiss, “Pure colors from core–shell quantum dots,” MRS Bull. 38(09), 696–702 (2013).
[Crossref]

Chen, R.

Y. Wang, V. D. Ta, Y. Gao, T. C. He, R. Chen, E. Mutlugun, H. V. Demir, and H. D. Sun, “Stimulated emission and lasing from CdSe/CdS/ZnS core-multi-shell quantum dots by simultaneous three-photon absorption,” Adv. Mater. 26(18), 2954–2961 (2014).
[Crossref] [PubMed]

Chen, Y.

Cheng, H.-C.

C.-H. Chang, H.-C. Cheng, Y.-J. Lu, K.-C. Tien, H.-W. Lin, C.-L. Lin, C.-J. Yang, and C.-C. Wu, “Enhancing color gamut of white OLED displays by using microcavity green pixels,” Org. Electron. 11(2), 247–254 (2010).
[Crossref]

Chiu, T.-L.

C.-H. Hsiao, Y.-H. Lan, P.-Y. Lee, T.-L. Chiu, and J.-H. Lee, “White organic light-emitting devices with ultra-high color stability over wide luminance range,” Org. Electron. 12(3), 547–555 (2011).
[Crossref]

Cho, K.-S.

K.-S. Cho, E. K. Lee, W.-J. Joo, E. Jang, T.-H. Kim, S. J. Lee, S.-J. Kwon, J. Y. Han, B.-K. Kim, B. L. Choi, and J. M. Kim, “High-performance crosslinked colloidal quantum-dot light-emitting diodes,” Nat. Photonics 3(6), 341–345 (2009).
[Crossref]

Cho, T.-Y.

C.-L. Lin, T.-Y. Cho, C.-H. Chang, and C.-C. Wu, “Enhancing light outcoupling of organic light-emitting devices by locating emitters around the second antinode of the reflective metal electrode,” Appl. Phys. Lett. 88(8), 081114 (2006).
[Crossref]

Choi, B. L.

K.-S. Cho, E. K. Lee, W.-J. Joo, E. Jang, T.-H. Kim, S. J. Lee, S.-J. Kwon, J. Y. Han, B.-K. Kim, B. L. Choi, and J. M. Kim, “High-performance crosslinked colloidal quantum-dot light-emitting diodes,” Nat. Photonics 3(6), 341–345 (2009).
[Crossref]

Chuang, C.-N.

M. K. Leung, W.-H. Yang, C.-N. Chuang, J.-H. Lee, C.-F. Lin, M.-K. Wei, and Y.-H. Liu, “1,3,4-Oxadiazole containing silanes as novel hosts for blue phosphorescent organic light emitting diodes,” Org. Lett. 14(19), 4986–4989 (2012).
[Crossref] [PubMed]

Chung, S.

S. Chung, J.-H. Lee, J. Jeong, J.-J. Kim, and Y. Hong, “Substrate thermal conductivity effect on heat dissipation and lifetime improvement of organic light-emitting diodes,” Appl. Phys. Lett. 94(25), 253302 (2009).
[Crossref]

Coe-Sullivan, S.

B. S. Mashford, M. Stevenson, Z. Popovic, C. Hamilton, Z. Zhou, C. Breen, J. Steckel, V. Bulovic, M. Bawendi, S. Coe-Sullivan, and P. T. Kazlas, “High-efficiency quantum-dot light-emitting devices with enhanced charge injection,” Nat. Photonics 7(5), 407–412 (2013).
[Crossref]

G. J. Supran, Y. Shirasaki, K. W. Song, J.-M. Caruge, P. T. Kazlas, S. Coe-Sullivan, T. L. Andrew, M. G. Bawendi, and V. Bulović, “QLEDs for displays and solid-state lighting,” MRS Bull. 38(09), 703–711 (2013).
[Crossref]

H. P. Yoon, Y. Lee, C. D. Bohn, S.-H. Ko, A. G. Gianfrancesco, J. S. Steckel, S. Coe-Sullivan, A. A. Talin, and N. B. Zhitenev, “High-resolution photocurrent microscopy using near-field cathodoluminescence of quantum dots,” AIP Adv. 3(6), 062112 (2013).
[Crossref]

Dang, C.

X. Yang, E. Mutlugun, C. Dang, K. Dev, Y. Gao, S. T. Tan, X. W. Sun, and H. V. Demir, “Highly flexible, electrically driven, top-emitting, quantum dot light-emitting stickers,” ACS Nano 8(8), 8224–8231 (2014).
[Crossref] [PubMed]

Demir, H. V.

Y. Wang, V. D. Ta, Y. Gao, T. C. He, R. Chen, E. Mutlugun, H. V. Demir, and H. D. Sun, “Stimulated emission and lasing from CdSe/CdS/ZnS core-multi-shell quantum dots by simultaneous three-photon absorption,” Adv. Mater. 26(18), 2954–2961 (2014).
[Crossref] [PubMed]

B. Guzelturk, P. L. H. Martinez, Q. Zhang, Q. Xiong, H. Sun, X. W. Sun, A. O. Govorov, and H. V. Demir, “Excitonics of semiconductor quantum dots and wires for lighting and displays,” Laser Photonics Rev. 8(1), 73–93 (2014).
[Crossref]

X. Yang, E. Mutlugun, C. Dang, K. Dev, Y. Gao, S. T. Tan, X. W. Sun, and H. V. Demir, “Highly flexible, electrically driven, top-emitting, quantum dot light-emitting stickers,” ACS Nano 8(8), 8224–8231 (2014).
[Crossref] [PubMed]

Dev, K.

X. Yang, E. Mutlugun, C. Dang, K. Dev, Y. Gao, S. T. Tan, X. W. Sun, and H. V. Demir, “Highly flexible, electrically driven, top-emitting, quantum dot light-emitting stickers,” ACS Nano 8(8), 8224–8231 (2014).
[Crossref] [PubMed]

Ding, I. K.

J. Zhao, J. A. Bardecker, A. M. Munro, M. S. Liu, Y. Niu, I. K. Ding, J. Luo, B. Chen, A. K. Y. Jen, and D. S. Ginger, “Efficient CdSe/CdS quantum dot light-emitting diodes using a thermally polymerized hole transport layer,” Nano Lett. 6(3), 463–467 (2006).
[Crossref] [PubMed]

Döhler, G. H.

R. Windisch, P. Heremans, A. Knobloch, P. Kiesel, G. H. Döhler, B. Dutta, and G. Borghs, “Light-emitting diodes with 31% external quantum efficiency by outcoupling of lateral waveguide modes,” Appl. Phys. Lett. 74(16), 2256–2258 (1999).
[Crossref]

Dutta, B.

R. Windisch, P. Heremans, A. Knobloch, P. Kiesel, G. H. Döhler, B. Dutta, and G. Borghs, “Light-emitting diodes with 31% external quantum efficiency by outcoupling of lateral waveguide modes,” Appl. Phys. Lett. 74(16), 2256–2258 (1999).
[Crossref]

Endo, A.

J. Frischeisen, D. Yokoyama, A. Endo, C. Adachi, and W. Brütting, “Increased light outcoupling efficiency in dye-doped small molecule organic light-emitting diodes with horizontally oriented emitters,” Org. Electron. 12(5), 809–817 (2011).
[Crossref]

Euisoo, K.

Eunyoung, C.

Forrest, S. R.

V. Bulović, A. Shoustikov, M. A. Baldo, E. Bose, V. G. Kozlov, M. E. Thompson, and S. R. Forrest, “Bright, saturated, red-to-yellow organic light-emitting devices based on polarization-induced spectral shifts,” Chem. Phys. Lett. 287(3–4), 455–460 (1998).
[Crossref]

Frischeisen, J.

W. Brütting, J. Frischeisen, T. D. Schmidt, B. J. Scholz, and C. Mayr, “Device efficiency of organic light-emitting diodes: progress by improved light outcoupling,” Phys. Status Solidi A 210(1), 44–65 (2013).
[Crossref]

J. Frischeisen, D. Yokoyama, A. Endo, C. Adachi, and W. Brütting, “Increased light outcoupling efficiency in dye-doped small molecule organic light-emitting diodes with horizontally oriented emitters,” Org. Electron. 12(5), 809–817 (2011).
[Crossref]

S. Nowy, B. C. Krummacher, J. Frischeisen, N. A. Reinke, and W. Brütting, “Light extraction and optical loss mechanisms in organic light-emitting diodes: Influence of the emitter quantum efficiency,” J. Appl. Phys. 104(12), 123109 (2008).
[Crossref]

Furno, M.

R. Meerheim, M. Furno, S. Hofmann, B. Lüssem, and K. Leo, “Quantification of energy loss mechanisms in organic light-emitting diodes,” Appl. Phys. Lett. 97(25), 253305 (2010).
[Crossref]

Gao, Y.

X. Yang, E. Mutlugun, C. Dang, K. Dev, Y. Gao, S. T. Tan, X. W. Sun, and H. V. Demir, “Highly flexible, electrically driven, top-emitting, quantum dot light-emitting stickers,” ACS Nano 8(8), 8224–8231 (2014).
[Crossref] [PubMed]

Y. Wang, V. D. Ta, Y. Gao, T. C. He, R. Chen, E. Mutlugun, H. V. Demir, and H. D. Sun, “Stimulated emission and lasing from CdSe/CdS/ZnS core-multi-shell quantum dots by simultaneous three-photon absorption,” Adv. Mater. 26(18), 2954–2961 (2014).
[Crossref] [PubMed]

Ge, Z.

Geffroy, B.

B. Geffroy, P. le Roy, and C. Prat, “Organic light-emitting diode (OLED) technology: materials, devices and display technologies,” Polym. Int. 55(6), 572–582 (2006).
[Crossref]

Gianfrancesco, A. G.

H. P. Yoon, Y. Lee, C. D. Bohn, S.-H. Ko, A. G. Gianfrancesco, J. S. Steckel, S. Coe-Sullivan, A. A. Talin, and N. B. Zhitenev, “High-resolution photocurrent microscopy using near-field cathodoluminescence of quantum dots,” AIP Adv. 3(6), 062112 (2013).
[Crossref]

Ginger, D. S.

J. Zhao, J. A. Bardecker, A. M. Munro, M. S. Liu, Y. Niu, I. K. Ding, J. Luo, B. Chen, A. K. Y. Jen, and D. S. Ginger, “Efficient CdSe/CdS quantum dot light-emitting diodes using a thermally polymerized hole transport layer,” Nano Lett. 6(3), 463–467 (2006).
[Crossref] [PubMed]

Govorov, A. O.

B. Guzelturk, P. L. H. Martinez, Q. Zhang, Q. Xiong, H. Sun, X. W. Sun, A. O. Govorov, and H. V. Demir, “Excitonics of semiconductor quantum dots and wires for lighting and displays,” Laser Photonics Rev. 8(1), 73–93 (2014).
[Crossref]

Guzelturk, B.

B. Guzelturk, P. L. H. Martinez, Q. Zhang, Q. Xiong, H. Sun, X. W. Sun, A. O. Govorov, and H. V. Demir, “Excitonics of semiconductor quantum dots and wires for lighting and displays,” Laser Photonics Rev. 8(1), 73–93 (2014).
[Crossref]

Hamilton, C.

B. S. Mashford, M. Stevenson, Z. Popovic, C. Hamilton, Z. Zhou, C. Breen, J. Steckel, V. Bulovic, M. Bawendi, S. Coe-Sullivan, and P. T. Kazlas, “High-efficiency quantum-dot light-emitting devices with enhanced charge injection,” Nat. Photonics 7(5), 407–412 (2013).
[Crossref]

Han, J. Y.

K.-S. Cho, E. K. Lee, W.-J. Joo, E. Jang, T.-H. Kim, S. J. Lee, S.-J. Kwon, J. Y. Han, B.-K. Kim, B. L. Choi, and J. M. Kim, “High-performance crosslinked colloidal quantum-dot light-emitting diodes,” Nat. Photonics 3(6), 341–345 (2009).
[Crossref]

He, T. C.

Y. Wang, V. D. Ta, Y. Gao, T. C. He, R. Chen, E. Mutlugun, H. V. Demir, and H. D. Sun, “Stimulated emission and lasing from CdSe/CdS/ZnS core-multi-shell quantum dots by simultaneous three-photon absorption,” Adv. Mater. 26(18), 2954–2961 (2014).
[Crossref] [PubMed]

Heremans, P.

R. Windisch, P. Heremans, A. Knobloch, P. Kiesel, G. H. Döhler, B. Dutta, and G. Borghs, “Light-emitting diodes with 31% external quantum efficiency by outcoupling of lateral waveguide modes,” Appl. Phys. Lett. 74(16), 2256–2258 (1999).
[Crossref]

Ho, Y.-H.

K.-Y. Chen, J.-H. Lee, M.-K. Wei, Y.-T. Chang, Y.-H. Ho, J.-R. Lin, and H. Y. Lin, “Device-dependent angular luminance enhancement and optical responses of organic light-emitting devices with a microlens-array film,” J. Soc. Inf. Disp. 19(1), 21–28 (2011).
[Crossref]

Hofmann, S.

S. Hofmann, M. Thomschke, B. Lüssem, and K. Leo, “Top-emitting organic light-emitting diodes,” Opt. Express 19(106), A1250–A1264 (2011).
[Crossref] [PubMed]

R. Meerheim, M. Furno, S. Hofmann, B. Lüssem, and K. Leo, “Quantification of energy loss mechanisms in organic light-emitting diodes,” Appl. Phys. Lett. 97(25), 253305 (2010).
[Crossref]

Holloway, P. H.

L. Qian, Y. Zheng, J. Xue, and P. H. Holloway, “Stable and efficient quantum-dot light-emitting diodes based on solution-processed multilayer structures,” Nat. Photonics 5(9), 543–548 (2011).
[Crossref]

Hong, Q.

Hong, Y.

S. Chung, J.-H. Lee, J. Jeong, J.-J. Kim, and Y. Hong, “Substrate thermal conductivity effect on heat dissipation and lifetime improvement of organic light-emitting diodes,” Appl. Phys. Lett. 94(25), 253302 (2009).
[Crossref]

Horst, G.

G. Horst, “Light extraction from organic light emitting diode substrates: simulation and experiment,” Jpn. J. Appl. Phys. 46(7A7R), 4125–4137 (2007).
[Crossref]

Hsiao, C.-C.

Hsiao, C.-H.

C.-H. Hsiao, Y.-H. Lan, P.-Y. Lee, T.-L. Chiu, and J.-H. Lee, “White organic light-emitting devices with ultra-high color stability over wide luminance range,” Org. Electron. 12(3), 547–555 (2011).
[Crossref]

Insung, S.

Jang, E.

K.-S. Cho, E. K. Lee, W.-J. Joo, E. Jang, T.-H. Kim, S. J. Lee, S.-J. Kwon, J. Y. Han, B.-K. Kim, B. L. Choi, and J. M. Kim, “High-performance crosslinked colloidal quantum-dot light-emitting diodes,” Nat. Photonics 3(6), 341–345 (2009).
[Crossref]

Jang, J.

A. Castan, H.-M. Kim, and J. Jang, “All-solution-processed inverted quantum-dot light-emitting diodes,” ACS Appl. Mater. Interfaces 6(4), 2508–2515 (2014).
[Crossref] [PubMed]

H.-M. Kim, A. R. Mohd Yusoff, T.-W. Kim, Y.-G. Seol, H.-P. Kim, and J. Jang, “Semi-transparent quantum-dot light emitting diodes with an inverted structure,” J. Mater. Chem. C 2(12), 2259–2265 (2014).
[Crossref]

Jen, A. K. Y.

J. Zhao, J. A. Bardecker, A. M. Munro, M. S. Liu, Y. Niu, I. K. Ding, J. Luo, B. Chen, A. K. Y. Jen, and D. S. Ginger, “Efficient CdSe/CdS quantum dot light-emitting diodes using a thermally polymerized hole transport layer,” Nano Lett. 6(3), 463–467 (2006).
[Crossref] [PubMed]

Jeong, J.

S. Chung, J.-H. Lee, J. Jeong, J.-J. Kim, and Y. Hong, “Substrate thermal conductivity effect on heat dissipation and lifetime improvement of organic light-emitting diodes,” Appl. Phys. Lett. 94(25), 253302 (2009).
[Crossref]

Joo, W.-J.

K.-S. Cho, E. K. Lee, W.-J. Joo, E. Jang, T.-H. Kim, S. J. Lee, S.-J. Kwon, J. Y. Han, B.-K. Kim, B. L. Choi, and J. M. Kim, “High-performance crosslinked colloidal quantum-dot light-emitting diodes,” Nat. Photonics 3(6), 341–345 (2009).
[Crossref]

Kazlas, P. T.

B. S. Mashford, M. Stevenson, Z. Popovic, C. Hamilton, Z. Zhou, C. Breen, J. Steckel, V. Bulovic, M. Bawendi, S. Coe-Sullivan, and P. T. Kazlas, “High-efficiency quantum-dot light-emitting devices with enhanced charge injection,” Nat. Photonics 7(5), 407–412 (2013).
[Crossref]

G. J. Supran, Y. Shirasaki, K. W. Song, J.-M. Caruge, P. T. Kazlas, S. Coe-Sullivan, T. L. Andrew, M. G. Bawendi, and V. Bulović, “QLEDs for displays and solid-state lighting,” MRS Bull. 38(09), 703–711 (2013).
[Crossref]

Kiang, Y.-W.

Kiesel, P.

R. Windisch, P. Heremans, A. Knobloch, P. Kiesel, G. H. Döhler, B. Dutta, and G. Borghs, “Light-emitting diodes with 31% external quantum efficiency by outcoupling of lateral waveguide modes,” Appl. Phys. Lett. 74(16), 2256–2258 (1999).
[Crossref]

Kim, B.-K.

K.-S. Cho, E. K. Lee, W.-J. Joo, E. Jang, T.-H. Kim, S. J. Lee, S.-J. Kwon, J. Y. Han, B.-K. Kim, B. L. Choi, and J. M. Kim, “High-performance crosslinked colloidal quantum-dot light-emitting diodes,” Nat. Photonics 3(6), 341–345 (2009).
[Crossref]

Kim, H.-M.

A. Castan, H.-M. Kim, and J. Jang, “All-solution-processed inverted quantum-dot light-emitting diodes,” ACS Appl. Mater. Interfaces 6(4), 2508–2515 (2014).
[Crossref] [PubMed]

H.-M. Kim, A. R. Mohd Yusoff, T.-W. Kim, Y.-G. Seol, H.-P. Kim, and J. Jang, “Semi-transparent quantum-dot light emitting diodes with an inverted structure,” J. Mater. Chem. C 2(12), 2259–2265 (2014).
[Crossref]

Kim, H.-P.

H.-M. Kim, A. R. Mohd Yusoff, T.-W. Kim, Y.-G. Seol, H.-P. Kim, and J. Jang, “Semi-transparent quantum-dot light emitting diodes with an inverted structure,” J. Mater. Chem. C 2(12), 2259–2265 (2014).
[Crossref]

Kim, J. M.

K.-S. Cho, E. K. Lee, W.-J. Joo, E. Jang, T.-H. Kim, S. J. Lee, S.-J. Kwon, J. Y. Han, B.-K. Kim, B. L. Choi, and J. M. Kim, “High-performance crosslinked colloidal quantum-dot light-emitting diodes,” Nat. Photonics 3(6), 341–345 (2009).
[Crossref]

Kim, J.-J.

S. Chung, J.-H. Lee, J. Jeong, J.-J. Kim, and Y. Hong, “Substrate thermal conductivity effect on heat dissipation and lifetime improvement of organic light-emitting diodes,” Appl. Phys. Lett. 94(25), 253302 (2009).
[Crossref]

Kim, T.-H.

K.-S. Cho, E. K. Lee, W.-J. Joo, E. Jang, T.-H. Kim, S. J. Lee, S.-J. Kwon, J. Y. Han, B.-K. Kim, B. L. Choi, and J. M. Kim, “High-performance crosslinked colloidal quantum-dot light-emitting diodes,” Nat. Photonics 3(6), 341–345 (2009).
[Crossref]

Kim, T.-W.

H.-M. Kim, A. R. Mohd Yusoff, T.-W. Kim, Y.-G. Seol, H.-P. Kim, and J. Jang, “Semi-transparent quantum-dot light emitting diodes with an inverted structure,” J. Mater. Chem. C 2(12), 2259–2265 (2014).
[Crossref]

Klimov, V. I.

W. K. Bae, S. Brovelli, and V. I. Klimov, “Spectroscopic insights into the performance of quantum dot light-emitting diodes,” MRS Bull. 38(09), 721–730 (2013).
[Crossref]

W. K. Bae, Y.-S. Park, J. Lim, D. Lee, L. A. Padilha, H. McDaniel, I. Robel, C. Lee, J. M. Pietryga, and V. I. Klimov, “Controlling the influence of Auger recombination on the performance of quantum-dot light-emitting diodes,” Nat Commun 4, 2661 (2013).
[Crossref] [PubMed]

Knobloch, A.

R. Windisch, P. Heremans, A. Knobloch, P. Kiesel, G. H. Döhler, B. Dutta, and G. Borghs, “Light-emitting diodes with 31% external quantum efficiency by outcoupling of lateral waveguide modes,” Appl. Phys. Lett. 74(16), 2256–2258 (1999).
[Crossref]

Ko, S.-H.

H. P. Yoon, Y. Lee, C. D. Bohn, S.-H. Ko, A. G. Gianfrancesco, J. S. Steckel, S. Coe-Sullivan, A. A. Talin, and N. B. Zhitenev, “High-resolution photocurrent microscopy using near-field cathodoluminescence of quantum dots,” AIP Adv. 3(6), 062112 (2013).
[Crossref]

Kovalenko, M. V.

D. V. Talapin, J.-S. Lee, M. V. Kovalenko, and E. V. Shevchenko, “Prospects of colloidal nanocrystals for electronic and optoelectronic applications,” Chem. Rev. 110(1), 389–458 (2010).
[Crossref] [PubMed]

Kozlov, V. G.

V. Bulović, A. Shoustikov, M. A. Baldo, E. Bose, V. G. Kozlov, M. E. Thompson, and S. R. Forrest, “Bright, saturated, red-to-yellow organic light-emitting devices based on polarization-induced spectral shifts,” Chem. Phys. Lett. 287(3–4), 455–460 (1998).
[Crossref]

Krummacher, B. C.

S. Nowy, B. C. Krummacher, J. Frischeisen, N. A. Reinke, and W. Brütting, “Light extraction and optical loss mechanisms in organic light-emitting diodes: Influence of the emitter quantum efficiency,” J. Appl. Phys. 104(12), 123109 (2008).
[Crossref]

Kuo, C.-C.

Kwon, S.-J.

K.-S. Cho, E. K. Lee, W.-J. Joo, E. Jang, T.-H. Kim, S. J. Lee, S.-J. Kwon, J. Y. Han, B.-K. Kim, B. L. Choi, and J. M. Kim, “High-performance crosslinked colloidal quantum-dot light-emitting diodes,” Nat. Photonics 3(6), 341–345 (2009).
[Crossref]

Lan, Y.-H.

C.-H. Hsiao, Y.-H. Lan, P.-Y. Lee, T.-L. Chiu, and J.-H. Lee, “White organic light-emitting devices with ultra-high color stability over wide luminance range,” Org. Electron. 12(3), 547–555 (2011).
[Crossref]

le Roy, P.

B. Geffroy, P. le Roy, and C. Prat, “Organic light-emitting diode (OLED) technology: materials, devices and display technologies,” Polym. Int. 55(6), 572–582 (2006).
[Crossref]

Lee, C.

W. K. Bae, Y.-S. Park, J. Lim, D. Lee, L. A. Padilha, H. McDaniel, I. Robel, C. Lee, J. M. Pietryga, and V. I. Klimov, “Controlling the influence of Auger recombination on the performance of quantum-dot light-emitting diodes,” Nat Commun 4, 2661 (2013).
[Crossref] [PubMed]

Lee, D.

W. K. Bae, Y.-S. Park, J. Lim, D. Lee, L. A. Padilha, H. McDaniel, I. Robel, C. Lee, J. M. Pietryga, and V. I. Klimov, “Controlling the influence of Auger recombination on the performance of quantum-dot light-emitting diodes,” Nat Commun 4, 2661 (2013).
[Crossref] [PubMed]

Lee, E. K.

K.-S. Cho, E. K. Lee, W.-J. Joo, E. Jang, T.-H. Kim, S. J. Lee, S.-J. Kwon, J. Y. Han, B.-K. Kim, B. L. Choi, and J. M. Kim, “High-performance crosslinked colloidal quantum-dot light-emitting diodes,” Nat. Photonics 3(6), 341–345 (2009).
[Crossref]

Lee, J.-H.

M. K. Leung, W.-H. Yang, C.-N. Chuang, J.-H. Lee, C.-F. Lin, M.-K. Wei, and Y.-H. Liu, “1,3,4-Oxadiazole containing silanes as novel hosts for blue phosphorescent organic light emitting diodes,” Org. Lett. 14(19), 4986–4989 (2012).
[Crossref] [PubMed]

K.-Y. Chen, J.-H. Lee, M.-K. Wei, Y.-T. Chang, Y.-H. Ho, J.-R. Lin, and H. Y. Lin, “Device-dependent angular luminance enhancement and optical responses of organic light-emitting devices with a microlens-array film,” J. Soc. Inf. Disp. 19(1), 21–28 (2011).
[Crossref]

C.-H. Hsiao, Y.-H. Lan, P.-Y. Lee, T.-L. Chiu, and J.-H. Lee, “White organic light-emitting devices with ultra-high color stability over wide luminance range,” Org. Electron. 12(3), 547–555 (2011).
[Crossref]

S. Chung, J.-H. Lee, J. Jeong, J.-J. Kim, and Y. Hong, “Substrate thermal conductivity effect on heat dissipation and lifetime improvement of organic light-emitting diodes,” Appl. Phys. Lett. 94(25), 253302 (2009).
[Crossref]

J.-H. Lee, K.-Y. Chen, C.-C. Hsiao, H.-C. Chen, C.-H. Chang, Y.-W. Kiang, and C. C. Yang, “Radiation simulations of top-emitting organic light-emitting devices with two- and three-microcavity structures,” J. Display Technol. 2(2), 130–137 (2006).
[Crossref]

Lee, J.-S.

D. V. Talapin, J.-S. Lee, M. V. Kovalenko, and E. V. Shevchenko, “Prospects of colloidal nanocrystals for electronic and optoelectronic applications,” Chem. Rev. 110(1), 389–458 (2010).
[Crossref] [PubMed]

Lee, P.-Y.

C.-H. Hsiao, Y.-H. Lan, P.-Y. Lee, T.-L. Chiu, and J.-H. Lee, “White organic light-emitting devices with ultra-high color stability over wide luminance range,” Org. Electron. 12(3), 547–555 (2011).
[Crossref]

Lee, S. J.

K.-S. Cho, E. K. Lee, W.-J. Joo, E. Jang, T.-H. Kim, S. J. Lee, S.-J. Kwon, J. Y. Han, B.-K. Kim, B. L. Choi, and J. M. Kim, “High-performance crosslinked colloidal quantum-dot light-emitting diodes,” Nat. Photonics 3(6), 341–345 (2009).
[Crossref]

Lee, Y.

H. P. Yoon, Y. Lee, C. D. Bohn, S.-H. Ko, A. G. Gianfrancesco, J. S. Steckel, S. Coe-Sullivan, A. A. Talin, and N. B. Zhitenev, “High-resolution photocurrent microscopy using near-field cathodoluminescence of quantum dots,” AIP Adv. 3(6), 062112 (2013).
[Crossref]

Leo, K.

S. Reineke, M. Thomschke, B. Lüssem, and K. Leo, “White organic light-emitting diodes: status and perspective,” Rev. Mod. Phys. 85(3), 1245–1293 (2013).
[Crossref]

S. Hofmann, M. Thomschke, B. Lüssem, and K. Leo, “Top-emitting organic light-emitting diodes,” Opt. Express 19(106), A1250–A1264 (2011).
[Crossref] [PubMed]

R. Meerheim, M. Furno, S. Hofmann, B. Lüssem, and K. Leo, “Quantification of energy loss mechanisms in organic light-emitting diodes,” Appl. Phys. Lett. 97(25), 253305 (2010).
[Crossref]

Leung, M. K.

M. K. Leung, W.-H. Yang, C.-N. Chuang, J.-H. Lee, C.-F. Lin, M.-K. Wei, and Y.-H. Liu, “1,3,4-Oxadiazole containing silanes as novel hosts for blue phosphorescent organic light emitting diodes,” Org. Lett. 14(19), 4986–4989 (2012).
[Crossref] [PubMed]

Lim, J.

W. K. Bae, Y.-S. Park, J. Lim, D. Lee, L. A. Padilha, H. McDaniel, I. Robel, C. Lee, J. M. Pietryga, and V. I. Klimov, “Controlling the influence of Auger recombination on the performance of quantum-dot light-emitting diodes,” Nat Commun 4, 2661 (2013).
[Crossref] [PubMed]

Lin, C.-F.

M. K. Leung, W.-H. Yang, C.-N. Chuang, J.-H. Lee, C.-F. Lin, M.-K. Wei, and Y.-H. Liu, “1,3,4-Oxadiazole containing silanes as novel hosts for blue phosphorescent organic light emitting diodes,” Org. Lett. 14(19), 4986–4989 (2012).
[Crossref] [PubMed]

Lin, C.-L.

C.-H. Chang, H.-C. Cheng, Y.-J. Lu, K.-C. Tien, H.-W. Lin, C.-L. Lin, C.-J. Yang, and C.-C. Wu, “Enhancing color gamut of white OLED displays by using microcavity green pixels,” Org. Electron. 11(2), 247–254 (2010).
[Crossref]

C.-L. Lin, T.-Y. Cho, C.-H. Chang, and C.-C. Wu, “Enhancing light outcoupling of organic light-emitting devices by locating emitters around the second antinode of the reflective metal electrode,” Appl. Phys. Lett. 88(8), 081114 (2006).
[Crossref]

Lin, H. Y.

K.-Y. Chen, J.-H. Lee, M.-K. Wei, Y.-T. Chang, Y.-H. Ho, J.-R. Lin, and H. Y. Lin, “Device-dependent angular luminance enhancement and optical responses of organic light-emitting devices with a microlens-array film,” J. Soc. Inf. Disp. 19(1), 21–28 (2011).
[Crossref]

Lin, H.-W.

C.-H. Chang, H.-C. Cheng, Y.-J. Lu, K.-C. Tien, H.-W. Lin, C.-L. Lin, C.-J. Yang, and C.-C. Wu, “Enhancing color gamut of white OLED displays by using microcavity green pixels,” Org. Electron. 11(2), 247–254 (2010).
[Crossref]

Lin, J.-R.

K.-Y. Chen, J.-H. Lee, M.-K. Wei, Y.-T. Chang, Y.-H. Ho, J.-R. Lin, and H. Y. Lin, “Device-dependent angular luminance enhancement and optical responses of organic light-emitting devices with a microlens-array film,” J. Soc. Inf. Disp. 19(1), 21–28 (2011).
[Crossref]

Liu, M. S.

J. Zhao, J. A. Bardecker, A. M. Munro, M. S. Liu, Y. Niu, I. K. Ding, J. Luo, B. Chen, A. K. Y. Jen, and D. S. Ginger, “Efficient CdSe/CdS quantum dot light-emitting diodes using a thermally polymerized hole transport layer,” Nano Lett. 6(3), 463–467 (2006).
[Crossref] [PubMed]

Liu, Y.-H.

M. K. Leung, W.-H. Yang, C.-N. Chuang, J.-H. Lee, C.-F. Lin, M.-K. Wei, and Y.-H. Liu, “1,3,4-Oxadiazole containing silanes as novel hosts for blue phosphorescent organic light emitting diodes,” Org. Lett. 14(19), 4986–4989 (2012).
[Crossref] [PubMed]

Lu, R.

Lu, Y.-J.

C.-H. Chang, H.-C. Cheng, Y.-J. Lu, K.-C. Tien, H.-W. Lin, C.-L. Lin, C.-J. Yang, and C.-C. Wu, “Enhancing color gamut of white OLED displays by using microcavity green pixels,” Org. Electron. 11(2), 247–254 (2010).
[Crossref]

Luo, J.

J. Zhao, J. A. Bardecker, A. M. Munro, M. S. Liu, Y. Niu, I. K. Ding, J. Luo, B. Chen, A. K. Y. Jen, and D. S. Ginger, “Efficient CdSe/CdS quantum dot light-emitting diodes using a thermally polymerized hole transport layer,” Nano Lett. 6(3), 463–467 (2006).
[Crossref] [PubMed]

Luo, Z.

Lüssem, B.

S. Reineke, M. Thomschke, B. Lüssem, and K. Leo, “White organic light-emitting diodes: status and perspective,” Rev. Mod. Phys. 85(3), 1245–1293 (2013).
[Crossref]

S. Hofmann, M. Thomschke, B. Lüssem, and K. Leo, “Top-emitting organic light-emitting diodes,” Opt. Express 19(106), A1250–A1264 (2011).
[Crossref] [PubMed]

R. Meerheim, M. Furno, S. Hofmann, B. Lüssem, and K. Leo, “Quantification of energy loss mechanisms in organic light-emitting diodes,” Appl. Phys. Lett. 97(25), 253305 (2010).
[Crossref]

Martinez, P. L. H.

B. Guzelturk, P. L. H. Martinez, Q. Zhang, Q. Xiong, H. Sun, X. W. Sun, A. O. Govorov, and H. V. Demir, “Excitonics of semiconductor quantum dots and wires for lighting and displays,” Laser Photonics Rev. 8(1), 73–93 (2014).
[Crossref]

Mashford, B. S.

B. S. Mashford, M. Stevenson, Z. Popovic, C. Hamilton, Z. Zhou, C. Breen, J. Steckel, V. Bulovic, M. Bawendi, S. Coe-Sullivan, and P. T. Kazlas, “High-efficiency quantum-dot light-emitting devices with enhanced charge injection,” Nat. Photonics 7(5), 407–412 (2013).
[Crossref]

Maurice, A.

O. Chen, H. Wei, A. Maurice, M. Bawendi, and P. Reiss, “Pure colors from core–shell quantum dots,” MRS Bull. 38(09), 696–702 (2013).
[Crossref]

Mayr, C.

W. Brütting, J. Frischeisen, T. D. Schmidt, B. J. Scholz, and C. Mayr, “Device efficiency of organic light-emitting diodes: progress by improved light outcoupling,” Phys. Status Solidi A 210(1), 44–65 (2013).
[Crossref]

McDaniel, H.

W. K. Bae, Y.-S. Park, J. Lim, D. Lee, L. A. Padilha, H. McDaniel, I. Robel, C. Lee, J. M. Pietryga, and V. I. Klimov, “Controlling the influence of Auger recombination on the performance of quantum-dot light-emitting diodes,” Nat Commun 4, 2661 (2013).
[Crossref] [PubMed]

Meerheim, R.

R. Meerheim, M. Furno, S. Hofmann, B. Lüssem, and K. Leo, “Quantification of energy loss mechanisms in organic light-emitting diodes,” Appl. Phys. Lett. 97(25), 253305 (2010).
[Crossref]

Mladenovski, S.

Mohd Yusoff, A. R.

H.-M. Kim, A. R. Mohd Yusoff, T.-W. Kim, Y.-G. Seol, H.-P. Kim, and J. Jang, “Semi-transparent quantum-dot light emitting diodes with an inverted structure,” J. Mater. Chem. C 2(12), 2259–2265 (2014).
[Crossref]

Munro, A. M.

J. Zhao, J. A. Bardecker, A. M. Munro, M. S. Liu, Y. Niu, I. K. Ding, J. Luo, B. Chen, A. K. Y. Jen, and D. S. Ginger, “Efficient CdSe/CdS quantum dot light-emitting diodes using a thermally polymerized hole transport layer,” Nano Lett. 6(3), 463–467 (2006).
[Crossref] [PubMed]

Mutlugun, E.

X. Yang, E. Mutlugun, C. Dang, K. Dev, Y. Gao, S. T. Tan, X. W. Sun, and H. V. Demir, “Highly flexible, electrically driven, top-emitting, quantum dot light-emitting stickers,” ACS Nano 8(8), 8224–8231 (2014).
[Crossref] [PubMed]

Y. Wang, V. D. Ta, Y. Gao, T. C. He, R. Chen, E. Mutlugun, H. V. Demir, and H. D. Sun, “Stimulated emission and lasing from CdSe/CdS/ZnS core-multi-shell quantum dots by simultaneous three-photon absorption,” Adv. Mater. 26(18), 2954–2961 (2014).
[Crossref] [PubMed]

Neyts, K.

Neyts, K. A.

Niu, Y.

J. Zhao, J. A. Bardecker, A. M. Munro, M. S. Liu, Y. Niu, I. K. Ding, J. Luo, B. Chen, A. K. Y. Jen, and D. S. Ginger, “Efficient CdSe/CdS quantum dot light-emitting diodes using a thermally polymerized hole transport layer,” Nano Lett. 6(3), 463–467 (2006).
[Crossref] [PubMed]

Nowy, S.

S. Nowy, B. C. Krummacher, J. Frischeisen, N. A. Reinke, and W. Brütting, “Light extraction and optical loss mechanisms in organic light-emitting diodes: Influence of the emitter quantum efficiency,” J. Appl. Phys. 104(12), 123109 (2008).
[Crossref]

Padilha, L. A.

W. K. Bae, Y.-S. Park, J. Lim, D. Lee, L. A. Padilha, H. McDaniel, I. Robel, C. Lee, J. M. Pietryga, and V. I. Klimov, “Controlling the influence of Auger recombination on the performance of quantum-dot light-emitting diodes,” Nat Commun 4, 2661 (2013).
[Crossref] [PubMed]

Park, Y.-S.

W. K. Bae, Y.-S. Park, J. Lim, D. Lee, L. A. Padilha, H. McDaniel, I. Robel, C. Lee, J. M. Pietryga, and V. I. Klimov, “Controlling the influence of Auger recombination on the performance of quantum-dot light-emitting diodes,” Nat Commun 4, 2661 (2013).
[Crossref] [PubMed]

Pavicic, D.

Pietryga, J. M.

W. K. Bae, Y.-S. Park, J. Lim, D. Lee, L. A. Padilha, H. McDaniel, I. Robel, C. Lee, J. M. Pietryga, and V. I. Klimov, “Controlling the influence of Auger recombination on the performance of quantum-dot light-emitting diodes,” Nat Commun 4, 2661 (2013).
[Crossref] [PubMed]

Poitras, D.

Popovic, Z.

B. S. Mashford, M. Stevenson, Z. Popovic, C. Hamilton, Z. Zhou, C. Breen, J. Steckel, V. Bulovic, M. Bawendi, S. Coe-Sullivan, and P. T. Kazlas, “High-efficiency quantum-dot light-emitting devices with enhanced charge injection,” Nat. Photonics 7(5), 407–412 (2013).
[Crossref]

Prat, C.

B. Geffroy, P. le Roy, and C. Prat, “Organic light-emitting diode (OLED) technology: materials, devices and display technologies,” Polym. Int. 55(6), 572–582 (2006).
[Crossref]

Py, C.

Qian, L.

L. Qian, Y. Zheng, J. Xue, and P. H. Holloway, “Stable and efficient quantum-dot light-emitting diodes based on solution-processed multilayer structures,” Nat. Photonics 5(9), 543–548 (2011).
[Crossref]

Reineke, S.

S. Reineke, M. Thomschke, B. Lüssem, and K. Leo, “White organic light-emitting diodes: status and perspective,” Rev. Mod. Phys. 85(3), 1245–1293 (2013).
[Crossref]

Reinke, N. A.

S. Nowy, B. C. Krummacher, J. Frischeisen, N. A. Reinke, and W. Brütting, “Light extraction and optical loss mechanisms in organic light-emitting diodes: Influence of the emitter quantum efficiency,” J. Appl. Phys. 104(12), 123109 (2008).
[Crossref]

Reiss, P.

O. Chen, H. Wei, A. Maurice, M. Bawendi, and P. Reiss, “Pure colors from core–shell quantum dots,” MRS Bull. 38(09), 696–702 (2013).
[Crossref]

Robel, I.

W. K. Bae, Y.-S. Park, J. Lim, D. Lee, L. A. Padilha, H. McDaniel, I. Robel, C. Lee, J. M. Pietryga, and V. I. Klimov, “Controlling the influence of Auger recombination on the performance of quantum-dot light-emitting diodes,” Nat Commun 4, 2661 (2013).
[Crossref] [PubMed]

Rothe, C.

Schmidt, T. D.

W. Brütting, J. Frischeisen, T. D. Schmidt, B. J. Scholz, and C. Mayr, “Device efficiency of organic light-emitting diodes: progress by improved light outcoupling,” Phys. Status Solidi A 210(1), 44–65 (2013).
[Crossref]

Scholz, B. J.

W. Brütting, J. Frischeisen, T. D. Schmidt, B. J. Scholz, and C. Mayr, “Device efficiency of organic light-emitting diodes: progress by improved light outcoupling,” Phys. Status Solidi A 210(1), 44–65 (2013).
[Crossref]

Seol, Y.-G.

H.-M. Kim, A. R. Mohd Yusoff, T.-W. Kim, Y.-G. Seol, H.-P. Kim, and J. Jang, “Semi-transparent quantum-dot light emitting diodes with an inverted structure,” J. Mater. Chem. C 2(12), 2259–2265 (2014).
[Crossref]

Seong-Sik, P.

Sessolo, M.

M. Sessolo and H. J. Bolink, “Hybrid organic-inorganic light-emitting diodes,” Adv. Mater. 23(16), 1829–1845 (2011).
[Crossref] [PubMed]

Seungwon, P.

Shevchenko, E. V.

D. V. Talapin, J.-S. Lee, M. V. Kovalenko, and E. V. Shevchenko, “Prospects of colloidal nanocrystals for electronic and optoelectronic applications,” Chem. Rev. 110(1), 389–458 (2010).
[Crossref] [PubMed]

Shirasaki, Y.

G. J. Supran, Y. Shirasaki, K. W. Song, J.-M. Caruge, P. T. Kazlas, S. Coe-Sullivan, T. L. Andrew, M. G. Bawendi, and V. Bulović, “QLEDs for displays and solid-state lighting,” MRS Bull. 38(09), 703–711 (2013).
[Crossref]

Shoustikov, A.

V. Bulović, A. Shoustikov, M. A. Baldo, E. Bose, V. G. Kozlov, M. E. Thompson, and S. R. Forrest, “Bright, saturated, red-to-yellow organic light-emitting devices based on polarization-induced spectral shifts,” Chem. Phys. Lett. 287(3–4), 455–460 (1998).
[Crossref]

Song, K. W.

G. J. Supran, Y. Shirasaki, K. W. Song, J.-M. Caruge, P. T. Kazlas, S. Coe-Sullivan, T. L. Andrew, M. G. Bawendi, and V. Bulović, “QLEDs for displays and solid-state lighting,” MRS Bull. 38(09), 703–711 (2013).
[Crossref]

Steckel, J.

B. S. Mashford, M. Stevenson, Z. Popovic, C. Hamilton, Z. Zhou, C. Breen, J. Steckel, V. Bulovic, M. Bawendi, S. Coe-Sullivan, and P. T. Kazlas, “High-efficiency quantum-dot light-emitting devices with enhanced charge injection,” Nat. Photonics 7(5), 407–412 (2013).
[Crossref]

Steckel, J. S.

H. P. Yoon, Y. Lee, C. D. Bohn, S.-H. Ko, A. G. Gianfrancesco, J. S. Steckel, S. Coe-Sullivan, A. A. Talin, and N. B. Zhitenev, “High-resolution photocurrent microscopy using near-field cathodoluminescence of quantum dots,” AIP Adv. 3(6), 062112 (2013).
[Crossref]

Stevenson, M.

B. S. Mashford, M. Stevenson, Z. Popovic, C. Hamilton, Z. Zhou, C. Breen, J. Steckel, V. Bulovic, M. Bawendi, S. Coe-Sullivan, and P. T. Kazlas, “High-efficiency quantum-dot light-emitting devices with enhanced charge injection,” Nat. Photonics 7(5), 407–412 (2013).
[Crossref]

Sun, H.

B. Guzelturk, P. L. H. Martinez, Q. Zhang, Q. Xiong, H. Sun, X. W. Sun, A. O. Govorov, and H. V. Demir, “Excitonics of semiconductor quantum dots and wires for lighting and displays,” Laser Photonics Rev. 8(1), 73–93 (2014).
[Crossref]

Sun, H. D.

Y. Wang, V. D. Ta, Y. Gao, T. C. He, R. Chen, E. Mutlugun, H. V. Demir, and H. D. Sun, “Stimulated emission and lasing from CdSe/CdS/ZnS core-multi-shell quantum dots by simultaneous three-photon absorption,” Adv. Mater. 26(18), 2954–2961 (2014).
[Crossref] [PubMed]

Sun, X. W.

B. Guzelturk, P. L. H. Martinez, Q. Zhang, Q. Xiong, H. Sun, X. W. Sun, A. O. Govorov, and H. V. Demir, “Excitonics of semiconductor quantum dots and wires for lighting and displays,” Laser Photonics Rev. 8(1), 73–93 (2014).
[Crossref]

X. Yang, E. Mutlugun, C. Dang, K. Dev, Y. Gao, S. T. Tan, X. W. Sun, and H. V. Demir, “Highly flexible, electrically driven, top-emitting, quantum dot light-emitting stickers,” ACS Nano 8(8), 8224–8231 (2014).
[Crossref] [PubMed]

Supran, G. J.

G. J. Supran, Y. Shirasaki, K. W. Song, J.-M. Caruge, P. T. Kazlas, S. Coe-Sullivan, T. L. Andrew, M. G. Bawendi, and V. Bulović, “QLEDs for displays and solid-state lighting,” MRS Bull. 38(09), 703–711 (2013).
[Crossref]

Ta, V. D.

Y. Wang, V. D. Ta, Y. Gao, T. C. He, R. Chen, E. Mutlugun, H. V. Demir, and H. D. Sun, “Stimulated emission and lasing from CdSe/CdS/ZnS core-multi-shell quantum dots by simultaneous three-photon absorption,” Adv. Mater. 26(18), 2954–2961 (2014).
[Crossref] [PubMed]

Talapin, D. V.

D. V. Talapin, J.-S. Lee, M. V. Kovalenko, and E. V. Shevchenko, “Prospects of colloidal nanocrystals for electronic and optoelectronic applications,” Chem. Rev. 110(1), 389–458 (2010).
[Crossref] [PubMed]

Talin, A. A.

H. P. Yoon, Y. Lee, C. D. Bohn, S.-H. Ko, A. G. Gianfrancesco, J. S. Steckel, S. Coe-Sullivan, A. A. Talin, and N. B. Zhitenev, “High-resolution photocurrent microscopy using near-field cathodoluminescence of quantum dots,” AIP Adv. 3(6), 062112 (2013).
[Crossref]

Tan, S. T.

X. Yang, E. Mutlugun, C. Dang, K. Dev, Y. Gao, S. T. Tan, X. W. Sun, and H. V. Demir, “Highly flexible, electrically driven, top-emitting, quantum dot light-emitting stickers,” ACS Nano 8(8), 8224–8231 (2014).
[Crossref] [PubMed]

Thompson, M. E.

V. Bulović, A. Shoustikov, M. A. Baldo, E. Bose, V. G. Kozlov, M. E. Thompson, and S. R. Forrest, “Bright, saturated, red-to-yellow organic light-emitting devices based on polarization-induced spectral shifts,” Chem. Phys. Lett. 287(3–4), 455–460 (1998).
[Crossref]

Thomschke, M.

S. Reineke, M. Thomschke, B. Lüssem, and K. Leo, “White organic light-emitting diodes: status and perspective,” Rev. Mod. Phys. 85(3), 1245–1293 (2013).
[Crossref]

S. Hofmann, M. Thomschke, B. Lüssem, and K. Leo, “Top-emitting organic light-emitting diodes,” Opt. Express 19(106), A1250–A1264 (2011).
[Crossref] [PubMed]

Tien, K.-C.

C.-H. Chang, H.-C. Cheng, Y.-J. Lu, K.-C. Tien, H.-W. Lin, C.-L. Lin, C.-J. Yang, and C.-C. Wu, “Enhancing color gamut of white OLED displays by using microcavity green pixels,” Org. Electron. 11(2), 247–254 (2010).
[Crossref]

Tsutsui, T.

T. Tsutsui, “Progress in electroluminescent devices using molecular thin films,” MRS Bull. 22(06), 39–45 (1997).
[Crossref]

Wang, Y.

Y. Wang, V. D. Ta, Y. Gao, T. C. He, R. Chen, E. Mutlugun, H. V. Demir, and H. D. Sun, “Stimulated emission and lasing from CdSe/CdS/ZnS core-multi-shell quantum dots by simultaneous three-photon absorption,” Adv. Mater. 26(18), 2954–2961 (2014).
[Crossref] [PubMed]

Wasey, J. A. E.

J. A. E. Wasey and W. L. Barnes, “Efficiency of spontaneous emission from planar microcavities,” J. Mod. Opt. 47(4), 725–741 (2000).
[Crossref]

Wei, H.

O. Chen, H. Wei, A. Maurice, M. Bawendi, and P. Reiss, “Pure colors from core–shell quantum dots,” MRS Bull. 38(09), 696–702 (2013).
[Crossref]

Wei, M.-K.

M. K. Leung, W.-H. Yang, C.-N. Chuang, J.-H. Lee, C.-F. Lin, M.-K. Wei, and Y.-H. Liu, “1,3,4-Oxadiazole containing silanes as novel hosts for blue phosphorescent organic light emitting diodes,” Org. Lett. 14(19), 4986–4989 (2012).
[Crossref] [PubMed]

K.-Y. Chen, J.-H. Lee, M.-K. Wei, Y.-T. Chang, Y.-H. Ho, J.-R. Lin, and H. Y. Lin, “Device-dependent angular luminance enhancement and optical responses of organic light-emitting devices with a microlens-array film,” J. Soc. Inf. Disp. 19(1), 21–28 (2011).
[Crossref]

Werner, A.

Windisch, R.

R. Windisch, P. Heremans, A. Knobloch, P. Kiesel, G. H. Döhler, B. Dutta, and G. Borghs, “Light-emitting diodes with 31% external quantum efficiency by outcoupling of lateral waveguide modes,” Appl. Phys. Lett. 74(16), 2256–2258 (1999).
[Crossref]

Wu, C.-C.

C.-H. Chang, H.-C. Cheng, Y.-J. Lu, K.-C. Tien, H.-W. Lin, C.-L. Lin, C.-J. Yang, and C.-C. Wu, “Enhancing color gamut of white OLED displays by using microcavity green pixels,” Org. Electron. 11(2), 247–254 (2010).
[Crossref]

C.-L. Lin, T.-Y. Cho, C.-H. Chang, and C.-C. Wu, “Enhancing light outcoupling of organic light-emitting devices by locating emitters around the second antinode of the reflective metal electrode,” Appl. Phys. Lett. 88(8), 081114 (2006).
[Crossref]

Wu, S.-T.

Xiong, Q.

B. Guzelturk, P. L. H. Martinez, Q. Zhang, Q. Xiong, H. Sun, X. W. Sun, A. O. Govorov, and H. V. Demir, “Excitonics of semiconductor quantum dots and wires for lighting and displays,” Laser Photonics Rev. 8(1), 73–93 (2014).
[Crossref]

Xu, D.

Xue, J.

L. Qian, Y. Zheng, J. Xue, and P. H. Holloway, “Stable and efficient quantum-dot light-emitting diodes based on solution-processed multilayer structures,” Nat. Photonics 5(9), 543–548 (2011).
[Crossref]

Yang, C. C.

Yang, C.-J.

C.-H. Chang, H.-C. Cheng, Y.-J. Lu, K.-C. Tien, H.-W. Lin, C.-L. Lin, C.-J. Yang, and C.-C. Wu, “Enhancing color gamut of white OLED displays by using microcavity green pixels,” Org. Electron. 11(2), 247–254 (2010).
[Crossref]

Yang, W.-H.

M. K. Leung, W.-H. Yang, C.-N. Chuang, J.-H. Lee, C.-F. Lin, M.-K. Wei, and Y.-H. Liu, “1,3,4-Oxadiazole containing silanes as novel hosts for blue phosphorescent organic light emitting diodes,” Org. Lett. 14(19), 4986–4989 (2012).
[Crossref] [PubMed]

Yang, X.

X. Yang, E. Mutlugun, C. Dang, K. Dev, Y. Gao, S. T. Tan, X. W. Sun, and H. V. Demir, “Highly flexible, electrically driven, top-emitting, quantum dot light-emitting stickers,” ACS Nano 8(8), 8224–8231 (2014).
[Crossref] [PubMed]

Yokoyama, D.

J. Frischeisen, D. Yokoyama, A. Endo, C. Adachi, and W. Brütting, “Increased light outcoupling efficiency in dye-doped small molecule organic light-emitting diodes with horizontally oriented emitters,” Org. Electron. 12(5), 809–817 (2011).
[Crossref]

Yoon, H. P.

H. P. Yoon, Y. Lee, C. D. Bohn, S.-H. Ko, A. G. Gianfrancesco, J. S. Steckel, S. Coe-Sullivan, A. A. Talin, and N. B. Zhitenev, “High-resolution photocurrent microscopy using near-field cathodoluminescence of quantum dots,” AIP Adv. 3(6), 062112 (2013).
[Crossref]

Zhang, Q.

B. Guzelturk, P. L. H. Martinez, Q. Zhang, Q. Xiong, H. Sun, X. W. Sun, A. O. Govorov, and H. V. Demir, “Excitonics of semiconductor quantum dots and wires for lighting and displays,” Laser Photonics Rev. 8(1), 73–93 (2014).
[Crossref]

Zhao, J.

J. Zhao, J. A. Bardecker, A. M. Munro, M. S. Liu, Y. Niu, I. K. Ding, J. Luo, B. Chen, A. K. Y. Jen, and D. S. Ginger, “Efficient CdSe/CdS quantum dot light-emitting diodes using a thermally polymerized hole transport layer,” Nano Lett. 6(3), 463–467 (2006).
[Crossref] [PubMed]

Zheng, Y.

L. Qian, Y. Zheng, J. Xue, and P. H. Holloway, “Stable and efficient quantum-dot light-emitting diodes based on solution-processed multilayer structures,” Nat. Photonics 5(9), 543–548 (2011).
[Crossref]

Zhitenev, N. B.

H. P. Yoon, Y. Lee, C. D. Bohn, S.-H. Ko, A. G. Gianfrancesco, J. S. Steckel, S. Coe-Sullivan, A. A. Talin, and N. B. Zhitenev, “High-resolution photocurrent microscopy using near-field cathodoluminescence of quantum dots,” AIP Adv. 3(6), 062112 (2013).
[Crossref]

Zhou, Z.

B. S. Mashford, M. Stevenson, Z. Popovic, C. Hamilton, Z. Zhou, C. Breen, J. Steckel, V. Bulovic, M. Bawendi, S. Coe-Sullivan, and P. T. Kazlas, “High-efficiency quantum-dot light-emitting devices with enhanced charge injection,” Nat. Photonics 7(5), 407–412 (2013).
[Crossref]

ACS Appl. Mater. Interfaces (1)

A. Castan, H.-M. Kim, and J. Jang, “All-solution-processed inverted quantum-dot light-emitting diodes,” ACS Appl. Mater. Interfaces 6(4), 2508–2515 (2014).
[Crossref] [PubMed]

ACS Nano (1)

X. Yang, E. Mutlugun, C. Dang, K. Dev, Y. Gao, S. T. Tan, X. W. Sun, and H. V. Demir, “Highly flexible, electrically driven, top-emitting, quantum dot light-emitting stickers,” ACS Nano 8(8), 8224–8231 (2014).
[Crossref] [PubMed]

Adv. Mater. (2)

M. Sessolo and H. J. Bolink, “Hybrid organic-inorganic light-emitting diodes,” Adv. Mater. 23(16), 1829–1845 (2011).
[Crossref] [PubMed]

Y. Wang, V. D. Ta, Y. Gao, T. C. He, R. Chen, E. Mutlugun, H. V. Demir, and H. D. Sun, “Stimulated emission and lasing from CdSe/CdS/ZnS core-multi-shell quantum dots by simultaneous three-photon absorption,” Adv. Mater. 26(18), 2954–2961 (2014).
[Crossref] [PubMed]

AIP Adv. (1)

H. P. Yoon, Y. Lee, C. D. Bohn, S.-H. Ko, A. G. Gianfrancesco, J. S. Steckel, S. Coe-Sullivan, A. A. Talin, and N. B. Zhitenev, “High-resolution photocurrent microscopy using near-field cathodoluminescence of quantum dots,” AIP Adv. 3(6), 062112 (2013).
[Crossref]

Appl. Phys. Lett. (4)

R. Meerheim, M. Furno, S. Hofmann, B. Lüssem, and K. Leo, “Quantification of energy loss mechanisms in organic light-emitting diodes,” Appl. Phys. Lett. 97(25), 253305 (2010).
[Crossref]

R. Windisch, P. Heremans, A. Knobloch, P. Kiesel, G. H. Döhler, B. Dutta, and G. Borghs, “Light-emitting diodes with 31% external quantum efficiency by outcoupling of lateral waveguide modes,” Appl. Phys. Lett. 74(16), 2256–2258 (1999).
[Crossref]

S. Chung, J.-H. Lee, J. Jeong, J.-J. Kim, and Y. Hong, “Substrate thermal conductivity effect on heat dissipation and lifetime improvement of organic light-emitting diodes,” Appl. Phys. Lett. 94(25), 253302 (2009).
[Crossref]

C.-L. Lin, T.-Y. Cho, C.-H. Chang, and C.-C. Wu, “Enhancing light outcoupling of organic light-emitting devices by locating emitters around the second antinode of the reflective metal electrode,” Appl. Phys. Lett. 88(8), 081114 (2006).
[Crossref]

Chem. Phys. Lett. (1)

V. Bulović, A. Shoustikov, M. A. Baldo, E. Bose, V. G. Kozlov, M. E. Thompson, and S. R. Forrest, “Bright, saturated, red-to-yellow organic light-emitting devices based on polarization-induced spectral shifts,” Chem. Phys. Lett. 287(3–4), 455–460 (1998).
[Crossref]

Chem. Rev. (1)

D. V. Talapin, J.-S. Lee, M. V. Kovalenko, and E. V. Shevchenko, “Prospects of colloidal nanocrystals for electronic and optoelectronic applications,” Chem. Rev. 110(1), 389–458 (2010).
[Crossref] [PubMed]

J. Appl. Phys. (1)

S. Nowy, B. C. Krummacher, J. Frischeisen, N. A. Reinke, and W. Brütting, “Light extraction and optical loss mechanisms in organic light-emitting diodes: Influence of the emitter quantum efficiency,” J. Appl. Phys. 104(12), 123109 (2008).
[Crossref]

J. Display Technol. (3)

J. Mater. Chem. C (1)

H.-M. Kim, A. R. Mohd Yusoff, T.-W. Kim, Y.-G. Seol, H.-P. Kim, and J. Jang, “Semi-transparent quantum-dot light emitting diodes with an inverted structure,” J. Mater. Chem. C 2(12), 2259–2265 (2014).
[Crossref]

J. Mod. Opt. (1)

J. A. E. Wasey and W. L. Barnes, “Efficiency of spontaneous emission from planar microcavities,” J. Mod. Opt. 47(4), 725–741 (2000).
[Crossref]

J. Opt. Soc. Am. A (1)

J. Soc. Inf. Disp. (1)

K.-Y. Chen, J.-H. Lee, M.-K. Wei, Y.-T. Chang, Y.-H. Ho, J.-R. Lin, and H. Y. Lin, “Device-dependent angular luminance enhancement and optical responses of organic light-emitting devices with a microlens-array film,” J. Soc. Inf. Disp. 19(1), 21–28 (2011).
[Crossref]

Jpn. J. Appl. Phys. (1)

G. Horst, “Light extraction from organic light emitting diode substrates: simulation and experiment,” Jpn. J. Appl. Phys. 46(7A7R), 4125–4137 (2007).
[Crossref]

Laser Photonics Rev. (1)

B. Guzelturk, P. L. H. Martinez, Q. Zhang, Q. Xiong, H. Sun, X. W. Sun, A. O. Govorov, and H. V. Demir, “Excitonics of semiconductor quantum dots and wires for lighting and displays,” Laser Photonics Rev. 8(1), 73–93 (2014).
[Crossref]

MRS Bull. (4)

W. K. Bae, S. Brovelli, and V. I. Klimov, “Spectroscopic insights into the performance of quantum dot light-emitting diodes,” MRS Bull. 38(09), 721–730 (2013).
[Crossref]

G. J. Supran, Y. Shirasaki, K. W. Song, J.-M. Caruge, P. T. Kazlas, S. Coe-Sullivan, T. L. Andrew, M. G. Bawendi, and V. Bulović, “QLEDs for displays and solid-state lighting,” MRS Bull. 38(09), 703–711 (2013).
[Crossref]

O. Chen, H. Wei, A. Maurice, M. Bawendi, and P. Reiss, “Pure colors from core–shell quantum dots,” MRS Bull. 38(09), 696–702 (2013).
[Crossref]

T. Tsutsui, “Progress in electroluminescent devices using molecular thin films,” MRS Bull. 22(06), 39–45 (1997).
[Crossref]

Nano Lett. (1)

J. Zhao, J. A. Bardecker, A. M. Munro, M. S. Liu, Y. Niu, I. K. Ding, J. Luo, B. Chen, A. K. Y. Jen, and D. S. Ginger, “Efficient CdSe/CdS quantum dot light-emitting diodes using a thermally polymerized hole transport layer,” Nano Lett. 6(3), 463–467 (2006).
[Crossref] [PubMed]

Nat Commun (1)

W. K. Bae, Y.-S. Park, J. Lim, D. Lee, L. A. Padilha, H. McDaniel, I. Robel, C. Lee, J. M. Pietryga, and V. I. Klimov, “Controlling the influence of Auger recombination on the performance of quantum-dot light-emitting diodes,” Nat Commun 4, 2661 (2013).
[Crossref] [PubMed]

Nat. Photonics (3)

B. S. Mashford, M. Stevenson, Z. Popovic, C. Hamilton, Z. Zhou, C. Breen, J. Steckel, V. Bulovic, M. Bawendi, S. Coe-Sullivan, and P. T. Kazlas, “High-efficiency quantum-dot light-emitting devices with enhanced charge injection,” Nat. Photonics 7(5), 407–412 (2013).
[Crossref]

L. Qian, Y. Zheng, J. Xue, and P. H. Holloway, “Stable and efficient quantum-dot light-emitting diodes based on solution-processed multilayer structures,” Nat. Photonics 5(9), 543–548 (2011).
[Crossref]

K.-S. Cho, E. K. Lee, W.-J. Joo, E. Jang, T.-H. Kim, S. J. Lee, S.-J. Kwon, J. Y. Han, B.-K. Kim, B. L. Choi, and J. M. Kim, “High-performance crosslinked colloidal quantum-dot light-emitting diodes,” Nat. Photonics 3(6), 341–345 (2009).
[Crossref]

Opt. Express (5)

Org. Electron. (3)

J. Frischeisen, D. Yokoyama, A. Endo, C. Adachi, and W. Brütting, “Increased light outcoupling efficiency in dye-doped small molecule organic light-emitting diodes with horizontally oriented emitters,” Org. Electron. 12(5), 809–817 (2011).
[Crossref]

C.-H. Chang, H.-C. Cheng, Y.-J. Lu, K.-C. Tien, H.-W. Lin, C.-L. Lin, C.-J. Yang, and C.-C. Wu, “Enhancing color gamut of white OLED displays by using microcavity green pixels,” Org. Electron. 11(2), 247–254 (2010).
[Crossref]

C.-H. Hsiao, Y.-H. Lan, P.-Y. Lee, T.-L. Chiu, and J.-H. Lee, “White organic light-emitting devices with ultra-high color stability over wide luminance range,” Org. Electron. 12(3), 547–555 (2011).
[Crossref]

Org. Lett. (1)

M. K. Leung, W.-H. Yang, C.-N. Chuang, J.-H. Lee, C.-F. Lin, M.-K. Wei, and Y.-H. Liu, “1,3,4-Oxadiazole containing silanes as novel hosts for blue phosphorescent organic light emitting diodes,” Org. Lett. 14(19), 4986–4989 (2012).
[Crossref] [PubMed]

Phys. Status Solidi A (1)

W. Brütting, J. Frischeisen, T. D. Schmidt, B. J. Scholz, and C. Mayr, “Device efficiency of organic light-emitting diodes: progress by improved light outcoupling,” Phys. Status Solidi A 210(1), 44–65 (2013).
[Crossref]

Polym. Int. (1)

B. Geffroy, P. le Roy, and C. Prat, “Organic light-emitting diode (OLED) technology: materials, devices and display technologies,” Polym. Int. 55(6), 572–582 (2006).
[Crossref]

Rev. Mod. Phys. (1)

S. Reineke, M. Thomschke, B. Lüssem, and K. Leo, “White organic light-emitting diodes: status and perspective,” Rev. Mod. Phys. 85(3), 1245–1293 (2013).
[Crossref]

Other (6)

J. F. Van Derlofske, J. M. Hillis, A. Lathrop, J. Wheatley, J. Thielen, and G. Benoit, “Illuminating the value of larger color gamuts for quantum dot displays,” SID Symp. Dig. Tech. Pap. 45(1), 237–240 (2014).

E. D. Palik, Handbook of Optical Constants of Solids (Academic, 1985).

C.-H. Oh, H.-J. Shin, W.-J. Nam, B.-C. Ahn, S.-Y. Cha, and S.-D. Yeo, “Technological progress and commercialization of OLED TV,” SID Symp. Dig. Tech. Pap. 44(1), 239–242 (2013).

C.-W. Han, K.-M. Kim, S.-J. Bae, H.-S. Choi, J.-M. Lee, T.-S. Kim, Y.-H. Tak, S.-Y. Cha, and B.-C. Ahn, “55-inch FHD OLED TV employing new tandem WOLEDs,” SID Symp. Dig. Tech. Pap. 43(1), 279–281 (2012).
[Crossref]

S. E. Braslavsky, “Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006),” Pure Appl. Chem. 79(3), 293–465 (2007).

P. Yeh, Optical Waves in Layered Media (Wiley, 1988).

Cited By

Optica participates in Crossref's Cited-By Linking service. Citing articles from Optica Publishing Group journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (14)

Fig. 1
Fig. 1 (a) Structure of the proposed QLED stack and (b) PL spectra of the QDs taken from [19].
Fig. 2
Fig. 2 (a) The device structure of the OLED stack and (b) the PL spectra of NPB:Ir(MDQ)2(acac) taken from [32].
Fig. 3
Fig. 3 Schematic drawing of the simplified three layer structure.
Fig. 4
Fig. 4 Simulated power dissipation spectra of (a) QLED and (b) BOLED.
Fig. 5
Fig. 5 Amount of power coupled to different optical channels for (a) QLED device and (b) BOLED device.
Fig. 6
Fig. 6 Simulated full power dissipation spectra of (a) QLED and (b) BOLED.
Fig. 7
Fig. 7 (a) Changing the proportions of different optical channels by tuning the BPhen:Cs layer thickness for the OLED structure, and (b) Changing the proportions of different optical channels by tuning the NPB layer thickness for the QLED structure.
Fig. 8
Fig. 8 Changing the fraction of power of different optical channels for the QLED structure by varying the ZnO layer thickness.
Fig. 9
Fig. 9 Amount of power coupled to different optical channels for the QLED device with a high refractive index (n = 1.8) substrate.
Fig. 10
Fig. 10 How the refractive index of the substrate affects different optical channel power proportion.
Fig. 11
Fig. 11 Full power dissipation spectra of the QLED with different substrate refractive indices: a) nsub = 1.8 b) nsub = 2.0 c) nsub = 2.2 d) nsub = 2.4.
Fig. 12
Fig. 12 Emission spectra of the (a) QLED stack (b) BOLED stack.
Fig. 13
Fig. 13 Calculated color shift of the proposed red QLED and the red OLED.
Fig. 14
Fig. 14 Simulated angular radiation pattern of the OLED and the QLED structures.

Tables (1)

Tables Icon

Table 1 Fractions of power coupled to different modes for the QLED stack with substrates having different refractive indices.

Equations (13)

Equations on this page are rendered with MathJax. Learn more.

I(λ,θ)= 1+ R T +2 R T cos( ϕ T + 4π n e acos( θ ) λ ) (1 R T R B ) 2 +4 R T R B sin 2 ( Δϕ 2 ) T B I 0 (λ).
Δϕ= 4π n e dcos( θ ) λ ϕ B ϕ T .
EQE=ηIQE=ηγ η S/T q eff ,
EQE=ηIQE=ηγ q eff .
q= k r k r + k nr ,
P=1q+qF=1q+q 0 K( k x )d k x .
q eff q = k r * k r * + k nr = F k r F k r + k nr = F qF+1q .
K= 1 3 K TMv + 2 3 ( K TMh + K TEh ),
K TMv = 3 2 Re[ k x 3 (1+ r TMv b e 2i k z b )(1+ r TMv t e 2i k z a ) k e k z 3 (1 r TMv b r TMv t e 2i k z (a+b) ) ], K TMh = 3 4 Re[ k x k z (1 r TMv b e 2i k z b )(1 r TMv t e 2i k z a ) k e 3 (1 r TMv b r TMv t e 2i k z (a+b) ) ], K TEh = 3 4 Re[ k x (1+ r TEv b e 2i k z b )(1+ r TEv t e 2i k z a ) k e k z (1 r TEv b r TEv t e 2i k z (a+b) ) ].
ε e f f = i d i / i ( d i / ε i ) , n e f f = Re ( ε e f f ) .
K TEh = 3 8 k x k e k z [ | 1+ r TEv b e 2i k z b | 2 | 1 r TEv b r TEv t e 2i k z (a+b) | 2 ( T TEv t + A TEv t )+ | 1+ r TEv t e 2i k z t | 2 | 1 r TEv b r TEv t e 2i k z (a+b) | 2 ( T TEv b + A TEv b )] = 3 8 k x k e k z [ | 1+ r TEv b e 2i k z b | 2 | 1 r TEv b r TEv t e 2i k z (a+b) | 2 ( T TEv t + T TEv b )+ | 1+ r TEv t e 2i k z t | 2 | 1 r TEv b r TEv t e 2i k z (a+b) | 2 ( A TEv t + A TEv b )] = K TEh T + K TEh A .
P=1q+qF=1q+q λ 1 λ 2 S(λ) 0 K( k x )d k x dλ .
q eff η= P dir / P tot .

Metrics