Abstract

To understand the chiroptical responses of polyfluorene–phenylene (PFP) films, circular dichroism (CD), surface-enhanced Raman scattering (SERS), attenuated total reflection (ATR), and spectroscopic ellipsometry studies were performed. The pristine PFP films exhibited significant CD at room temperature, and the chirality increased by thermal annealing at 120 °C (above the glass transition temperature). SERS and ATR spectra indicated that the chirality enhancement was due to the rearrangement of the polymer backbones on the glass substrate by thermal annealing and/or self-organization. In addition, comparison of PFP and polyfluorene polymers indicated that molecular structure of polymer backbone plays an important role in the chiroptical responses of the chiral polymers.

© 2016 Optical Society of America

Corrections

25 February 2016: A correction was made to the acknowledgments.

1. Introduction

Organic and polymer light-emitting devices have attracted considerable attention because of their high luminescence quantum yields, wide wavelength tunability, and easy processability. There have been many efforts to understand the underlying mechanism of electro-/photo-luminescence and to enhance the luminescence performance [1–5]. When light, from a light source or to a photodetector, propagates through optical components and materials, its propagation depends on its polarization and chirality. Therefore, control of the polarization and chirality of light is critical in device applications; this control can be achieved using various chiral media such as helical structures, natural chiral media, and synthesized chiral polymers. Traditionally, chiroptical properties of biomaterials and organic small molecules are often observed in limited condition such as liquid solution and self-assembled structure/gelatin [6–8]. In addition, chiral polymers can be fabricated as thin film using solution-processing techniques and these films exhibit high CD value [9–11]. Among these polymers, chiral polyfluorene (PF) derivatives exhibit significantly enhanced chirality in thin-film. Furthermore, chiral PF copolymers can provide wide wavelength tunability and easy processability. Many research groups studied device applications and chirality enhancement in PF films. The Neher group studied circularly polarized electroluminescence in liquid-crystalline chiral PFs [12, 13], and the Prasad group investigated the chirality and nonlinear optical properties of chiral PF polymers [14, 15]. In addition, the Bradley group reported linearly polarized luminescence in oriented PF films [16], and investigated the optical constants of PF films using spectroscopic ellipsometry [17]. Scherf and List studied the structure–property relationships of PFs [18]. The Meijer group demonstrated the formation of a chiral liquid crystalline phase in PF films using CD spectroscopy and polarized optical microscopy, and they studied the effect of molecular weight on the mesoscopic order of chiral fluorene homopolymer and copolymer films [19]. Finally, the Friend group studied the factors that affect the thin-film morphology of PF-based electroluminescent polymer blends using atomic force microscopy, micro-Raman spectroscopy, and X-ray photoelectron spectroscopy, and investigated the dependence of device performance on the phase separation of electroluminescent polymers [20]. However, to the best of our knowledge, systematic research on chiral polyfluorene-phenylene films using several optical spectroscopic methods such as CD, Raman spectroscopy, ATR, and spectroscopic ellipsometry has been limited.

In this study, we investigated the chiroptical properties of poly[(9,9-di((R)-3,7-dimethyloctyl)fluoren-2,7-diyl)-alt-(1,4-phenylene)] (PFP) films. After synthesizing the PFP polymer with its pendant alkyl groups, thin films were spin-coated on glass or gold substrate, and annealed above the glass transition temperature (Tg). Their chiroptical properties were measured by optical absorption and CD spectroscopy. The origin of the chirality enhancement in the solid film was investigated using spectroscopic ellipsometry, ATR, and surface-enhanced Raman spectroscopy. To determine the effect of the molecular structure of the polymer backbone on the chirality of the PFP film, PF polymer was synthesized, and thin films were prepared on glass or gold substrate, and annealed above Tg. The chiroptical properties of the PF films were compared with those of the PFP films.

2. Materials and experimental methods

The chiral PFP polymer was synthesized via the Suzuki coupling polymerization of 2,7-dibromo-9,9-bis((S)-3,7-dimethyloctyl)fluorene with 1,4-bis (4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzene [19], which is modified method described in the literature [21–23]. The synthetic procedure for PFP is as follows (Fig. 1): 2M K2CO3 (5 mL), Pd(PPh3)4 (22.8 mg, 20.0 µmol), and a trace amount of Aliquat 336 were added to a solution of 2,7-dibromo-9,9-bis((S)-3,7-dimethyloctyl)fluorene (0.25 g, 0.4 mmol) and 1,4-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzene (0.132 g, 0.4 mmol) in toluene (15 mL) under argon atmosphere. The mixture was stirred at 100 °C for 24 h. The cooled mixture was added to vigorously stirred methanol (200 mL) and the resulting precipitate was filtered. The crude product was purified by Soxhlet extraction with acetone, hexane, and chloroform successively. The chloroform fraction was concentrated and then precipitated into methanol to yield a light yellow solid (0.15 g, 74%. number average molecular weight (Mn) = 9.2 kDa, polydispersity index (PDI) = 1.74). Anal. Calcd for (C37H50S2)n: C, 84.35; H, 9.57; S, 6.09. Found: C, 84.13; H, 9.81; S, 6.32. The chiral PF (Mn = 7.7 kDa, PDI = 1.98) as reference polymer was also synthesized according to literature [21].

 

Fig. 1 (a) Synthetic procedure for and molecular structure of the PFP polymer with pendant alkyl groups. (b) Differential scanning calorimetry scan of the PFP polymer.

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Chiral PFP films were prepared on glass or gold substrate. The chiral polymer films were spin-coated on the substrate from a solution of the PFP in a mixture of chloroform and chlorobenzene (9:1 v/v %). The PFP films were annealed on a temperature-controlled hot plate under ambient conditions. For the gold-coated plates, a gold film (50 nm) was deposited on the glass plate using thermal evaporation at a pressure of 10−6 torr.

UV-visible absorption spectra were obtained using a diode-array spectrophotometer (Agilent, 8453, USA), and the CD spectra were measured using a spectropolarimeter (Jasco, J-815, Japan). The absorption and CD spectra were observed in the UV and visible regions. Raman spectra were measured at room temperature using a confocal Raman microscope (WITec, Alpha 300R, Germany) with 633-nm light emitted from a He–Ne laser. In order to obtain the Raman spectra, the laser beam was focused on the chiral polymer film using a microscope objective (100×). The optical constants were measured using variable-angle spectroscopic ellipsometry (Woollam, M-2000U, USA) and fixed angle small-spot ellipsometry (Woollam, RC2-XF, USA). Spectroscopic ellipsometry measurements were performed over a wavelength range from 250 to 1000 nm. The incidence angles were 60°, 65°, 70° and 75°. The optical constants of the PFP films were obtained from the measured ellipsometric angles. To observe the surface plasmon resonance effect, the ATR spectra were measured using variable-angle spectroscopic ellipsometry. The incidence angle was fixed at 45°, and the ATR spectra were obtained over a wavelength range from 300 to 1800 nm.

3. Results and discussion

The prepared PFP polymer with its pendant alkyl groups, synthesized as in Fig. 1(a), exhibited Mn and PDI values of 9.2 kDa and 1.74, respectively, which were determined by gel permeation chromatography (Waters GPC, Waters 515 pump, Waters 410 RI, 2 × PLgel Mixed-B) using polystyrene as the standard and chloroform as the eluent at 35 °C. Tgof the PFP polymer was estimated to be 65 °C by differential scanning calorimetry (Fig. 1(b)). To find a suitable thickness for the efficient generation of the CD effect in the PFP film, three films were prepared at different thicknesses by adjusting the rotating speed of the spin coater. The PFP1, PFP2, and PFP3 films were prepared on glass plates by spin coating at 5000, 2500, and 1000 rpm, respectively. The film thicknesses of the PFP1, PFP2, and PFP3 samples were estimated to be 37 nm, 53 nm, and 67 nm, respectively, from spectroscopic ellipsometry. Thermal annealing at 120 °C for 15 min was performed to improve the chiroptical properties of the PFP films.

Figure 2(a) presents the CD spectra of the PFP films. The CD spectra exhibit a strong negative band at 381 nm and weak positive bands at 331 /412 nm. For the negative peak, the magnitudes of the dips in the CD spectra are 47, 98, and 419 mdeg for PFP1, PFP2, and PFP3, respectively, with a larger dip in PFP3 than in PFP1 or PFP2. Figure 2(b) presents the CD spectrum of the annealed film (PFP3A). Notably, the magnitude of the dip in the CD spectrum of the annealed film (PFP3A) is much larger than that for the pristine films (PFP1, PFP2, and PFP3), although the peak absorbance is lower in the former than the latter. In general, the CD properties of a chiral polymer depend on several factors, such as the chirality and spatial arrangement of the polymer backbone, and the film thickness. Circular dichroism arises because of the different absorption by the chiral sample by left (L)– and right (R)–handed circularly polarized light. If the material is optically active, the transmitted wave will exhibit differential absorption between the left and right circularly polarized light. The ellipticity (θ) is defined as the arctangent of the ratio of the minor axis to the major axis,

θ(λ)=tan1(ERELER+EL)=tan1(1IL/IR1+IL/IR)=tan1(1ρ(λ)1+ρ(λ))  ,   
where
IL(R)(λ)=IL(R)0exp(4πλkL(R)),
ρ(λ)=IL(λ)/IR(λ)=exp(4πλΔk(λ))=exp(ΔA(λ)),
ΔA(λ)=AL(λ)AR(λ)=4πλΔk(λ)=4πλ[kL(λ)kR(λ)].
In Eqs. (1)-(4), λ is the wavelength, and is the path length. In Eq. (1), EL(ER) and IL (IR) are the amplitudes and light intensities of the left- (right-) circularly polarized light, respectively. In Eq. (4), AL and AR are the absorbance of the left- and right-circularly polarized light, respectively. For small CD values [(4π/λ) ∆k << 1], θ and ∆A are related by the following linearized equation:
θ(λ)ΔA(λ)4=πλΔk(λ)(radians)
To compensate for the effect of the film thickness on the CD of the chiral polymer, we calculated the dissymmetry factor (g-value) spectrum for each film, which is defined as the difference in the absorption between the left- and right-circularly polarized light (∆A) divided by the average absorption of the left- and right-circularly polarized light (Aavg).

 

Fig. 2 Circular dichroism spectra of the (a) pristine (PFP1, PFP2, PFP3) and (b) annealed (PFP2A, PFP3A) films. Dissymmetry factor (g–value) spectra of the (c) pristine and (d) annealed films.

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g(λ)=ΔAAavg=AL(λ)AR(λ)(AL(λ)+AR(λ)2)

Figure 2(c) presents the g-value spectra of the pristine films (PFP1, PFP2 and PFP3). The spectra exhibit a characteristic CD signature with a negative band at 383 nm and positive bands at 316 /422 nm. The relative ratios of the peak-to-valley CD variations in the g-value spectra of PFP1, PFP2, and PFP3 are 1.0, 2.1, and 8.6, respectively. The peak-to-valley CD variation is larger in PFP3 than PFP1 or PFP2. Figure 2(d) presents the g-value spectra of the annealed films (PFP2A and PFP3A). The peak g-values of the PFP2A and PFP3A films are increased to 23 and 91 times that of the pristine PFP1 film by thermal annealing. Strong chirality is observed in the solid film; however, this chirality disappears in the liquid phase. Thus, the room-temperature chirality of the pristine films (PFP1, PFP2 and PFP3) is thought to be related to the self-organization of the fluorene-phenylene backbones on the glass substrate. Thermal annealing can accelerate the rearrangement of the fluorine-phenylene backbones, such that the annealed PFP film exhibits strong chirality. The room temperature CD of the PFP polymers can be utilized in polarized light-emitting devices and polarization-dependent optical sensors.

Figure 3(a) presents the optical absorption spectra of the pristine and annealed PFP films. The absorption band between 300 and 420 nm is due to the π–π transition of the conjugated main chains. In addition, the absorption band between 200 and 250 nm is due to the π–π transition of the side chains. Absorption peaks of the main chains for PFP1, PFP2, and PFP3 are observed at 375, 374, and 372 nm, respectively, clearly showing a slight blue-shift in the wavelength as the film thickness increases. At the absorption peak, relative peak absorbance ratios of 1.0, 1.2, and 1.5 were observed for PFP1, PFP2, and PFP3, respectively. The peak absorbance is higher in PFP3 than PFP1 or PFP2. To determine the effect of annealing on the absorption spectrum, we also measured the optical absorption spectrum of the annealed film (PFP3A). The peak absorbance is lower in the annealed film (PFP3A) than the pristine film (PFP3). The absorption peak of the annealed film (PFP3A) is observed at 357 nm, and is significantly blue-shifted compared with the pristine film (PFP3). Figure 3(b) presents the optical absorption spectrum of the PFP polymer in chloroform solution as well as those of the PFP films. The absorption maximum of the pristine PFP1 film is similar to that of the PFP solution, and that of the pristine PFP3 film is slightly blue-shifted. In addition, the absorption peak of the annealed film (PFP3A) is significantly blue-shifted compared with the PFP solution or the pristine film. The blue shift is attributed to the rearrangement of the polymer backbones by thermal annealing or self-organization.

 

Fig. 3 (a) Absorption spectra of the pristine (PFP1, PFP2, PFP3) and annealed (PFP3A) films. (b) Normalized absorption spectra of the PFP films (PFP1, PFP3, PFP3A) and the PFP solution. In (b), the absorption spectra are expanded to show the blue shift of the absorption peak.

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To further study the effects of the molecular structure and spatial arrangement of the polymer backbones on the chirality of the polymer film, we examined the Raman spectra of the films. To avoid sample damage and/or local heating by the excitation light, we used SERS method. Figure 4(a) presents the SERS spectrum of the annealed PFP3A film. In this experiment, the SERS spectrum was obtained with an excitation power of 0.3 mW. For Raman measurement of the chiral polymer film on the glass substrate, an excitation power of 3.0 mW was required to obtain a Raman scattering intensity comparable to that obtained from the chiral polymer film on the gold layer using the SERS method. The SERS spectrum of the annealed PFP3A film exhibited many Raman peaks corresponding to specific functional groups of the PFP backbone. The strong Raman peak at 1605 cm−1 arises from the in-plane stretching mode of the phenylene rings in the polymer backbone [24, 25]. The peaks at 1282, 1302, and 1342 cm−1 have been mainly assigned to C−C stretching modes between phenylene rings [24, 25]. The 1133 cm−1 Raman peak is attributed to the C−H bending mode, which occurs in the plane of the phenylene ring [24, 25]. The weak Raman peak at 1418 cm−1 corresponds to a combined C−H bend and C−C stretch motion between adjacent monomers [26]. Figure 4(b) presents the SERS spectra of the pristine and annealed films (PFP1, PFP2, PFP3, and PFP3A) on the gold layer. The Raman peak intensities of PFP backbones are stronger in the annealed film (PFP3A) compared to the pristine films (PFP1, PFP2, PFP3), and are larger in PFP3 than in PFP1 or PFP2. This result supports that the rearrangement of the fluorine-phenylene backbones by thermal annealing should contribute to the chirality enhancement. Grell et al. proved that there exists the liquid crystalline ordering of polymer backbones in polyfluorene film using X-ray diffraction experiments [27]. The Meskers group demonstrated that left- and right-handed cholesterically ordered domains exist in a polyfluorene film [28], and the intensive chiroptical effect in annealed films could arise from a cholesteric-like arrangement of the fibrillar aggregates in the annealed films [29]. Therefore, Raman enhancement and chirality enhancement were thought to be related with liquid-crystalline arrangement of the fibrillar aggregates in the annealed films. In our PFP polymer, the alkyl side chains can help to form a helical arrangement of the polymer backbones. According to previous theoretical research on the effect of the side chains on the backbone conformation of chiral polyfluorenes [30, 31], the β-phase backbone conformation (a semicrystalline phase) is stabilized by the adoption of an anti-gauche-gauche (agg) side-chain conformation, and the γ-phase backbone conformation (a crystalline phase) is stabilized by the adoption of an all-anti (aaa) side-chain conformation. In general, thermal annealing can improve the crystallization of amorphous materials [32, 33]. Thus, it is possible to achieve chirality enhancement by thermal annealing at a temperaure higher than Tg.

 

Fig. 4 (a) Fit of the experimental Raman spectrum of the annealed PFP3A film to eight Lorentzian multipeaks. (b) SERS spectra of the pristine (PFP1, PFP2, PFP3) and annealed (PFP3A) films.

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To further study the chiroptical properties of the PFP films, we performed spectroscopic ellipsometry measurements of the PFP film. The optical constants of the PFP can be determined from the ellipsometric measurements. The ellipsometric angles of chiral polymer films and conjugated polymer films are better fitted by the anisotropic model than by the isotropic model [17]. In the anisotropic model, the chiral polymer film is described by the real (ne, no) and imaginary (ke, ko) parts of the complex refractive index for both ordinary (in-plane) and extraordinary (out-of-plane) polarizations. Figure 5(a) presents the refractive index and extinction coefficient spectra of the pristine PFP3 film. In the wavelength region near the absorption peak, the peak absorption of the ordinary (in-plane) polarization wave is lower than that of extraordinary (out-of-plane) polarization wave. As expected from Kramers-Kronig relations, the extraordinary refractive indices (ne) are different from the ordinary refractive indices (no), respectively, as observed in Fig. 5(a). Figure 5(b) shows the refractive index and extinction coefficient spectra of the annealed PFP3A film. In the wavelength region near the absorption peak, the peak absorption of the ordinary (in-plane) polarization wave is higher than that of extraordinary (out-of-plane) polarization wave. According to Kramers-Kronig relations, the ne values are different from the no values, respectively, as observed in Fig. 5(b). Principally, the anisotropic optical constants can be related to the ordering of polymer main chains. In the π–π transition of conjugated polymers, the anisotropic absorption can be produced by the alignment of main chains. The angular distribution of polymer chains is described by [34]

dπ2sin2θdπ2=11+kπz2kπx
Here, θ is the polar angle between the surface normal and the polymer main chains, and dπ is the transition dipole moment for the π–π transition. kπzand kπx are z- and x-components of the extinction coefficient for the π–π transition. The average polar angle of the polymer main chains is related to the ratio between z- and x-components of the extinction coefficient. Based on the measured ordinary and extraordinary extinction coefficients, the average polar angle of the polymer main chains in the annealed PFP film is estimated to be 58°. In the annealed PFP film, there is a significant tilt angle between the polymer main chains and the substrate plane, suggesting that the PFP helices obliquely align in the substrate. The CD and spectroscopic ellipsometry results indicate that there is a helical arrangement of the PFP backbones on the substrate.

 

Fig. 5 Refractive index and extinction coefficient spectra of the (a) pristine (PFP3) and (b) annealed (PFP3A) films.

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To understand the Raman enhancement by the PFP films on gold, we calculated the extinction spectrum of the PFP film on gold using Mie theory [35].

σext(λ)=18πNVλln(10)εd3/2εmI(λ)[(εmR(λ)+χεd(λ))2+(εmI(λ))2]
Here, εmR and εmI are the real and imaginary parts of the complex dielectric constant of gold, respectively. εd is the real part of the complex dielectric constant of the PFP film. V and N are the volume and the concentration of metal nanoparticles, respectively. χ is the shape factor of metal nanoparticle. σext is the extinction scattering cross section of metal nanoparticles. In this model, the surface roughness of the gold film plays a role of metal nanoparticles. The complex dielectric constants of the gold substrate and the PFP film were obtained from spectroscopic ellipsometry measurements. Figure 6(a) shows the extinction spectrum of the PFP films on gold calculated using Mie theory. Thus, we can expect the SPR in the visible region.

 

Fig. 6 (a) Extinction spectrum of the PFP film on gold by Mie theory. (b) ATR spectra of p-polarized light for the pristine (PFP1, PFP3) and annealed (PFP3A) films under the Kretschmann configuration. The ATR spectra of the PFP films are compared with that of the bare gold layer. In the ATR spectra, reflection losses of at the entrance and exit facets of the prism are corrected using Fresnel formulas.

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To confirm the SPR effect of the gold substrate, we performed ATR experiments for the gold. For the ATR experiment, we used the Kretschmann configuration with [prism–metal–chiral polymer–air] structure. A p-polarized light of 300~1800 nm is incident at 45° in the prism and the spectrum of reflected light is measured in the ATR system. Figure 6 presents the ATR spectra of the p-polarized light for the bare gold and the PFP films on gold. First, we consider the SPR effect of bare gold. The SPR wavelength of bare gold was observed at 610 nm. The width of SPR bands was 120 nm. When the Raman excitation wavelength is on or near resonance with the SPR wavelength of the gold substrate, local electromagnetic fields are amplified by factors of |E|2, leading to intense SERS signals [35]. Since the SPR wavelength of the gold at 610 nm is close to the Raman excitation wavelength (633 nm) and the optical field is confined near the gold surface, it seems that the gold substrate in the Raman scattering experiment may play a role as a hot plate for SERS signals of the PFP films, indicating that the SERS detection is based on the optical field confined near the gold surface.

Next, the SPR wavelengths of bare gold, PFP1/gold, PFP3/gold, and PFP3A/gold were observed at 610, 1090, 1410, and 1475 nm, respectively. The widths of SPR bands were 120, 145, 148, and 190 nm for gold, PFP1/gold, PFP3/gold, and PFP3A/gold, respectively. Therefore, the quality factors (Q=λ0/Δλ) were 0.20, 0.13, 0.11, and 0.13 nm for gold, PFP1/gold, PFP3/gold, and PFP3A/gold, respectively. SPR wavelength shift to the longer wavelength in Fig. 5 is attributed to the increase of the film thickness, consisting with the film thicknesses from the ellipsometric measurements. This result may suggest that the SERS effect can be observed at the SPR wavelength for the PFP film on gold. However, the SERS experiment used confocal microscope geometry, different from using the Kretschmann configuration for the ATR experiment. To use the gold substrate as a hot plate for SERS signals of the PFP films, it is efficient to use the SPR wavelength of the bare gold due to the optical field confinement near the gold substrate. Finally, we consider the reflectance values in the ATR spectra. At the SPR, the reflectance values of p-polarized light for gold, PFP1/gold, PFP3/gold, and PFP3A/gold were attenuated from total reflection due to the SPR effect of gold. The minimum reflectance (Rmin) of SPRs in PFP1/gold, PFP3/gold, and PFP3A/gold increased from zero reflectance (Rmin = 0) of bare gold. It is known that Rmin can be increased from 0 by adsorption of absorptive or chiral/anisotropic materials [36–39]. Since our PFP films are transparent in the 300~1800 nm wavelength regime, we can exclude the increase in Rmin by absorption effect. Because the polarization direction of the incident wave can be changed by the reflection at an anisotropic film–metal interface and the PFP films exhibit significant CD, the increase in Rmin might be attributed to the chiral film on gold.

Next, we investigated the effect of the fluorene–phenylene repeating unit on the chiroptical properties of the PFP. For this purpose, we synthesized a PF polymer with pendant alkyl groups (Fig. 7). The PF film was prepared on glass or gold substrate by spin coating at 1000 rpm, respectively. The film thickness of the PF sample was estimated to be 54 nm from spectroscopic ellipsometry. The chiroptical properties of the PF polymer films were measured using optical absorption and CD spectroscopic techniques. Figures 7(a) and 7(b) present the optical absorption and CD spectra of the PF films, respectively. A comparison of Figs. 3 and 7 reveals that the spectra of the annealed PFP film are similar to those of the annealed PF film. Figure 7(c) presents the SERS spectrum of the annealed PF film. A comparison of Figs. 4 and 7 shows that the Raman spectrum of the annealed PF film is similar to that of the annealed PFP film, except that an additional Raman peak at 1195 cm−1 is observed in the PFP film. These results suggest that the spatial rearrangement of the polymer backbones plays an important role in the chiroptical responses of the PFP and PF polymers. Figure 7(d) presents the SERS spectra of the pristine and annealed PF films on the gold layer. The Raman peak intensities of PF backbones are stronger in the annealed film than in the pristine films. These results suggest that chirality enhancement in PF is attributed to the rearrangement of the polymer backbones by thermal annealing at a temperature higher than Tg. In addition, the CD spectra of the pristine PF films are different from those of the pristine PFP films. That is, the pristine PFP3 film exhibited significant CD at room temperature; however the pristine PF film did not exhibit significant CD at room temperature. A possible reason for the room-temperature chirality in the PFP film is the reduction in steric hindrance, which is attributed to the molecular structure of the fluorene–phenylene repeating unit in the polymer backbone. The molecular structures of PFP and PF differ from each other. As illustrated in Fig. 8, the optimized geometries of PFP and PF polymers indicate that there is more available space in the PFP compared with the PF. Thus, the steric effect of PFP is weaker than that of PF. The reduced steric hindrance facilitates the self-organization of the polymer backbones in the PFP film, resulting in the significant chirality at room temperature.

 

Fig. 7 (a) Optical absorption and (b) CD spectra of the pristine (PF) and annealed (PF-A) films. (c) Fit of the experimental Raman spectrum of the annealed PF-A film to eight Lorentzian multipeaks. (d) SERS spectra of the pristine and annealed films. In (a), the inset figure shows the molecular structure of the PF polymer with pendant alkyl groups.

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Fig. 8 Optimized geometries of (a) PF and (b) PFP polymers with pendant alkyl groups. In figure, (F), fluorene; (P), phenylene; (A), alkyl side chains.

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4. Conclusions

The chiroptical properties of the PFP polymer films were investigated using CD, SERS, ATR, and spectroscopic ellipsometry. The PFP polymer with pendant alkyl groups was synthesized, and thin films were spin-coated on glass or gold substrate. The film thicknesses of the PFP1, PFP2, and PFP3 samples were estimated to be 37 nm, 53 nm, and 67 nm, respectively, from spectroscopic ellipsometry. The pristine PFP films exhibited significant CD at room temperature, and the chirality increased by thermal annealing at 120 °C. The room-temperature chirality of the pristine film is thought to be related to the self-organization of the fluorene–phenylene backbones on the glass substrate. Thermal annealing can accelerate the rearrangement of the fluorene–phenylene backbones such that the annealed film exhibits strong chirality.

SERS analyses supported the hypothesis that the rearrangement of the fluorine-phenylene backbones by thermal annealing should contribute to the chirality enhancement. The SERS spectra of the PFP polymer films on gold exhibited many Raman peaks corresponding to the specific functional groups of the PFP backbone. The Raman peak intensities were stronger in the annealed film than in the pristine film. In addition, comparison of PFP and PF polymers revealed that the molecular structure of the polymer backbone plays an important role in the chiroptical responses of the chiral polymers.

Acknowledgments

This research was supported by Basic Science Research Program through the National Research Foundation of Korea funded by the Korean government [Grant numbers 2015R1D1A1A01057501 (Lee), NRF-2010-0027963 (PBRC)], and in part by Kwangwoon University in 2015. This research was supported by the National Research Foundation of Korea (NRF2012R1A2A1A01008797).

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9. R. Fiesel and U. Scherf, “Aggregation-induced CD effects in chiral poly(2,5-dialkoxy-1,4-phenylene)s,” Acta Polym. 49(8), 445–449 (1998). [CrossRef]  

10. R. Fiesel, C. E. Halkyard, M. E. Rampey, L. Kloppenburg, S. L. Studer-Martinez, U. Scherf, and U. H. F. Bunz, “Aggregation and chiroptical behavior of a high molecular weight chirally substituted dialkylpoly(p-phenyleneethynylene),” Macromol. Rapid Commun. 20(3), 107–111 (1999). [CrossRef]  

11. M. M. Bournan and E. W. Meijer, “Stereomutation in optically active regioregular polythiophenes,” Adv. Mater. 7(4), 385–387 (1995). [CrossRef]  

12. M. Oda, H. G. Nothofer, U. Scherf, S. C. J. Meskers, and D. Neher, “Circularly polarized electroluminescence from liquid‐crystalline chiral polyfluorenes,” Adv. Mater. 12(5), 362–365 (2000). [CrossRef]  

13. M. Oda, H. G. Nothofer, U. Scherf, I. V. Sunjic, D. Richter, W. Regenstein, and D. Neher, “Chiroptical properties of chiral substituted polyfluorenes,” Macromolecules 35(18), 6792–6798 (2002). [CrossRef]  

14. H. S. Oh, G. S. He, W. C. Law, A. Baev, H. Jee, X. Liu, A. Urbas, C. W. Lee, B. L. Choi, M. T. Swihart, and P. N. Prasad, “Manipulating nanoscale interactions in a polymer nanocomposite for chiral control of linear and nonlinear optical functions,” Adv. Mater. 26(10), 1607–1611 (2014). [CrossRef]   [PubMed]  

15. H. S. Oh, S. Liu, H. Jee, A. Baev, M. T. Swihart, and P. N. Prasad, “Chiral poly(fluorene-alt-benzothiadiazole) (PFBT) and nanocomposites with gold nanoparticles: plasmonically and structurally enhanced chirality,” J. Am. Chem. Soc. 132(49), 17346–17348 (2010). [CrossRef]   [PubMed]  

16. M. Grell and D. D. C. Bradley, “Polarized luminescence from oriented molecular materials,” Adv. Mater. 11(11), 895–905 (1999). [CrossRef]  

17. M. Campoy-Quiles, G. Heliotis, R. Xia, M. Ariu, M. Pintani, P. Etchegoin, and D. D. C. Bradley, “Ellipsometric characterization of the optical constants of polyfluorene gain media,” Adv. Funct. Mater. 15(6), 925–933 (2005). [CrossRef]  

18. U. Scherf and E. J. List, “Semiconducting polyfluorenes–Towards reliable structure–property relationships,” Adv. Mater. 14(7), 477–487 (2002). [CrossRef]  

19. R. Abbel, A. P. H. J. Schenning, and E. W. Meijer, “Molecular weight optimum in the mesoscopic order of chiral fluorene copolymer films,” Macromolecules 41(20), 7497–7504 (2008). [CrossRef]  

20. J. S. Kim, P. K. H. Ho, C. E. Murphy, and R. H. Friend, “Phase separation in polyfluorene-based conjugated polymer blends: Lateral and vertical analysis of blend spin-cast thin films,” Macromolecules 37(8), 2861–2871 (2004). [CrossRef]  

21. G. S. He, M. J. Cho, W. J. Kim, A. Baev, A. Urbas, and P. N. Prasad, “Polarimetric z-scan study of nonlinear chiroptic properties of chiral polyfluorene,” Adv. Opt. Mater. 1(10), 763–767 (2013). [CrossRef]  

22. J. C. Yan, X. Cheng, Q. L. Zhou, and J. Pei, “Chiral polyfluorene derivatives: Synthesis, chiroptical properties, and investigation of the structure-property relationships,” Macromolecules 40(4), 832–839 (2007). [CrossRef]  

23. M. T. Bernius, M. Inbasekaran, J. O’Brien, and W. Wu, “Progress with light-emitting polymers,” Adv. Mater. 12(23), 1737–1750 (2000). [CrossRef]  

24. W. C. Tsoi and D. G. Lidzey, “Raman spectroscopy of fluorene oligomers in the α-, β-and γ-phases,” J. Phys. Condens. Matter 20(12), 125213 (2008). [CrossRef]  

25. C. Volz, M. Arif, and S. Guha, “Conformations in dioctyl substituted polyfluorene: A combined theoretical and experimental Raman scattering study,” J. Chem. Phys. 126(6), 064905 (2007). [CrossRef]   [PubMed]  

26. S. Guha, M. Knaapila, D. Moghe, Z. Konopkova, M. Torkkeli, M. Fritsch, and U. Scherf, “Persistence of nematic liquid crystalline phase in a polyfluorene‐based organic semiconductor: A high pressure study,” J. Polym. Sci., B, Polym. Phys. 52(15), 1014–1023 (2014). [CrossRef]  

27. M. Grell, D. D. C. Bradley, G. Ungar, J. Hill, and K. S. Whitehead, “Interplay of physical structure and photophysics for a liquid crystalline polyfluorene,” Macromolecules 32(18), 5810–5817 (1999). [CrossRef]  

28. M. Savoini, P. Biagioni, S. C. J. Meskers, L. Duo, B. Hecht, and M. Finazzi, “Spontaneous formation of left-and right-handed cholesterically ordered domains in an enantiopure chiral polyfluorene film,” J. Phys. Chem. Lett. 2(12), 1359–1362 (2011). [CrossRef]  

29. G. Lakhwani, J. Gielen, M. Kemerink, P. C. M. Christianen, R. A. J. Janssen, and S. C. J. Meskers, “Intensive chiroptical properties of chiral polyfluorenes associated with fibril formation,” J. Phys. Chem. B 113(43), 14047–14051 (2009). [CrossRef]   [PubMed]  

30. W. Chunwaschirasiri, B. Tanto, D. L. Huber, and M. J. Winokur, “Chain conformations and photoluminescence of poly(di-n-octylfluorene),” Phys. Rev. Lett. 94(10), 107402 (2005). [CrossRef]   [PubMed]  

31. M. Arif, C. Volz, and S. Guha, “Chain morphologies in semicrystalline polyfluorene: Evidence from Raman scattering,” Phys. Rev. Lett. 96(2), 025503 (2006). [CrossRef]   [PubMed]  

32. B. Nowacki, H. Oh, C. Zanlorenzi, H. Jee, A. Baev, P. N. Prasad, and L. Akcelrud, “Design and synthesis of polymers for chiral photonics,” Macromolecules 46(18), 7158–7165 (2013). [CrossRef]  

33. G. J. Lee, J. Park, E. Kim, Y. Lee, K. Kim, H. Cheong, C. Yoon, Y. D. Son, and J. Jang, “Microstructure of femtosecond laser-induced grating in amorphous silicon,” Opt. Express 13(17), 6445–6453 (2005). [CrossRef]   [PubMed]  

34. D. McBranch, I. H. Campbell, D. L. Smith, and J. P. Ferraris, “Optical determination of chain orientation in electroluminescent polymer films,” Appl. Phys. Lett. 66(10), 1175–1177 (1995). [CrossRef]  

35. P. L. Stiles, J. A. Dieringer, N. C. Shah, and R. P. Van Duyne, “Surface-enhanced Raman spectroscopy,” Annu. Rev. Anal. Chem. (Palo Alto, Calif.) 1(1), 601–626 (2008). [CrossRef]   [PubMed]  

36. A. A. Kolomenskii, P. D. Gershon, and H. A. Schuessler, “Surface-plasmon resonance spectrometry and characterization of absorbing liquids,” Appl. Opt. 39(19), 3314–3320 (2000). [CrossRef]   [PubMed]  

37. W. P. Chen and J. M. Chen, “Use of surface plasma waves for determination of the thickness and optical constants of thin metallic films,” J. Opt. Soc. Am. 71(2), 189–191 (1981). [CrossRef]  

38. M. E. Caldwell and E. M. Yeatman, “Surface-plasmon spatial light modulators based on liquid crystal,” Appl. Opt. 31(20), 3880–3891 (1992). [CrossRef]   [PubMed]  

39. I. Abdulhalim, “Surface plasmon TE and TM waves at the anisotropic film–metal interface,” J. Opt. A, Pure Appl. Opt. 11(1), 015002 (2009). [CrossRef]  

References

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  1. M. Gross, D. C. Muller, H. G. Nothofer, U. Scherf, D. Neher, C. Brauchle, and K. Meerholz, “Improving the performance of doped π-conjugated polymers for use in organic light-emitting diodes,” Nature 405(6787), 661–665 (2000).
    [Crossref] [PubMed]
  2. T. Miteva, A. Meisel, W. Knoll, H. G. Nothofer, U. Scherf, D. C. Muller, and D. Neher, “Improving the performance of polyfluorene‐based organic light‐emitting diodes via end‐capping,” Adv. Mater. 13(8), 565–570 (2001).
    [Crossref]
  3. M. J. Cho, S. J. Kim, S. H. Yoon, J. Shin, T. R. Hong, H. J. Kim, Y. H. Son, J. S. Kang, H. A. Um, T. W. Lee, J. K. Bin, B. S. Lee, J. H. Yang, G. S. Chae, J. H. Kwon, and D. H. Choi, “New bipolar host materials for realizing blue phosphorescent organic light-emitting diodes with high efficiency at 1000 cd/m2.,” ACS Appl. Mater. Interfaces 6(22), 19808–19815 (2014).
    [Crossref] [PubMed]
  4. H. S. Kang, K. H. Kim, M. S. Kim, K. T. Park, K. M. Kim, T. H. Lee, C. Y. Lee, J. Joo, D. W. Lee, Y. R. Hong, K. Kim, G. J. Lee, and J. I. Jin, “Electrical characteristics of light-emitting diode based on poly(p-phenylenevinylene) derivatives: CzEH-PPV and OxdEH-PPV,” Synth. Met. 130(3), 279–283 (2002).
    [Crossref]
  5. G. J. Lee, K. Kim, and J. I. Jin, “Mechanism of one-and two-photon absorption induced photoluminescence in PPV type, electroluminescent polymer,” Opt. Commun. 203(1-2), 151–157 (2002).
    [Crossref]
  6. M. Liu, L. Zhang, and T. Wang, “Supramolecular chirality in self-assembled systems,” Chem. Rev. 115(15), 7304–7397 (2015).
    [Crossref] [PubMed]
  7. S. J. George, T. F. A. de Greef, R. Bovee, J. L. J. van Dongen, A. P. H. J. Schenning, and E. W. Meijer, “Photodimerization processes in self-assembled chiral oligo(p-phenylenevinylene) bolaamphiphiles,” Chem. Asian J. 4(6), 910–917 (2009).
    [Crossref] [PubMed]
  8. A. R. A. Palmans and E. W. Meijer, “Amplification of chirality in dynamic supramolecular aggregates,” Angew. Chem. Int. Ed. Engl. 46(47), 8948–8968 (2007).
    [Crossref] [PubMed]
  9. R. Fiesel and U. Scherf, “Aggregation-induced CD effects in chiral poly(2,5-dialkoxy-1,4-phenylene)s,” Acta Polym. 49(8), 445–449 (1998).
    [Crossref]
  10. R. Fiesel, C. E. Halkyard, M. E. Rampey, L. Kloppenburg, S. L. Studer-Martinez, U. Scherf, and U. H. F. Bunz, “Aggregation and chiroptical behavior of a high molecular weight chirally substituted dialkylpoly(p-phenyleneethynylene),” Macromol. Rapid Commun. 20(3), 107–111 (1999).
    [Crossref]
  11. M. M. Bournan and E. W. Meijer, “Stereomutation in optically active regioregular polythiophenes,” Adv. Mater. 7(4), 385–387 (1995).
    [Crossref]
  12. M. Oda, H. G. Nothofer, U. Scherf, S. C. J. Meskers, and D. Neher, “Circularly polarized electroluminescence from liquid‐crystalline chiral polyfluorenes,” Adv. Mater. 12(5), 362–365 (2000).
    [Crossref]
  13. M. Oda, H. G. Nothofer, U. Scherf, I. V. Sunjic, D. Richter, W. Regenstein, and D. Neher, “Chiroptical properties of chiral substituted polyfluorenes,” Macromolecules 35(18), 6792–6798 (2002).
    [Crossref]
  14. H. S. Oh, G. S. He, W. C. Law, A. Baev, H. Jee, X. Liu, A. Urbas, C. W. Lee, B. L. Choi, M. T. Swihart, and P. N. Prasad, “Manipulating nanoscale interactions in a polymer nanocomposite for chiral control of linear and nonlinear optical functions,” Adv. Mater. 26(10), 1607–1611 (2014).
    [Crossref] [PubMed]
  15. H. S. Oh, S. Liu, H. Jee, A. Baev, M. T. Swihart, and P. N. Prasad, “Chiral poly(fluorene-alt-benzothiadiazole) (PFBT) and nanocomposites with gold nanoparticles: plasmonically and structurally enhanced chirality,” J. Am. Chem. Soc. 132(49), 17346–17348 (2010).
    [Crossref] [PubMed]
  16. M. Grell and D. D. C. Bradley, “Polarized luminescence from oriented molecular materials,” Adv. Mater. 11(11), 895–905 (1999).
    [Crossref]
  17. M. Campoy-Quiles, G. Heliotis, R. Xia, M. Ariu, M. Pintani, P. Etchegoin, and D. D. C. Bradley, “Ellipsometric characterization of the optical constants of polyfluorene gain media,” Adv. Funct. Mater. 15(6), 925–933 (2005).
    [Crossref]
  18. U. Scherf and E. J. List, “Semiconducting polyfluorenes–Towards reliable structure–property relationships,” Adv. Mater. 14(7), 477–487 (2002).
    [Crossref]
  19. R. Abbel, A. P. H. J. Schenning, and E. W. Meijer, “Molecular weight optimum in the mesoscopic order of chiral fluorene copolymer films,” Macromolecules 41(20), 7497–7504 (2008).
    [Crossref]
  20. J. S. Kim, P. K. H. Ho, C. E. Murphy, and R. H. Friend, “Phase separation in polyfluorene-based conjugated polymer blends: Lateral and vertical analysis of blend spin-cast thin films,” Macromolecules 37(8), 2861–2871 (2004).
    [Crossref]
  21. G. S. He, M. J. Cho, W. J. Kim, A. Baev, A. Urbas, and P. N. Prasad, “Polarimetric z-scan study of nonlinear chiroptic properties of chiral polyfluorene,” Adv. Opt. Mater. 1(10), 763–767 (2013).
    [Crossref]
  22. J. C. Yan, X. Cheng, Q. L. Zhou, and J. Pei, “Chiral polyfluorene derivatives: Synthesis, chiroptical properties, and investigation of the structure-property relationships,” Macromolecules 40(4), 832–839 (2007).
    [Crossref]
  23. M. T. Bernius, M. Inbasekaran, J. O’Brien, and W. Wu, “Progress with light-emitting polymers,” Adv. Mater. 12(23), 1737–1750 (2000).
    [Crossref]
  24. W. C. Tsoi and D. G. Lidzey, “Raman spectroscopy of fluorene oligomers in the α-, β-and γ-phases,” J. Phys. Condens. Matter 20(12), 125213 (2008).
    [Crossref]
  25. C. Volz, M. Arif, and S. Guha, “Conformations in dioctyl substituted polyfluorene: A combined theoretical and experimental Raman scattering study,” J. Chem. Phys. 126(6), 064905 (2007).
    [Crossref] [PubMed]
  26. S. Guha, M. Knaapila, D. Moghe, Z. Konopkova, M. Torkkeli, M. Fritsch, and U. Scherf, “Persistence of nematic liquid crystalline phase in a polyfluorene‐based organic semiconductor: A high pressure study,” J. Polym. Sci., B, Polym. Phys. 52(15), 1014–1023 (2014).
    [Crossref]
  27. M. Grell, D. D. C. Bradley, G. Ungar, J. Hill, and K. S. Whitehead, “Interplay of physical structure and photophysics for a liquid crystalline polyfluorene,” Macromolecules 32(18), 5810–5817 (1999).
    [Crossref]
  28. M. Savoini, P. Biagioni, S. C. J. Meskers, L. Duo, B. Hecht, and M. Finazzi, “Spontaneous formation of left-and right-handed cholesterically ordered domains in an enantiopure chiral polyfluorene film,” J. Phys. Chem. Lett. 2(12), 1359–1362 (2011).
    [Crossref]
  29. G. Lakhwani, J. Gielen, M. Kemerink, P. C. M. Christianen, R. A. J. Janssen, and S. C. J. Meskers, “Intensive chiroptical properties of chiral polyfluorenes associated with fibril formation,” J. Phys. Chem. B 113(43), 14047–14051 (2009).
    [Crossref] [PubMed]
  30. W. Chunwaschirasiri, B. Tanto, D. L. Huber, and M. J. Winokur, “Chain conformations and photoluminescence of poly(di-n-octylfluorene),” Phys. Rev. Lett. 94(10), 107402 (2005).
    [Crossref] [PubMed]
  31. M. Arif, C. Volz, and S. Guha, “Chain morphologies in semicrystalline polyfluorene: Evidence from Raman scattering,” Phys. Rev. Lett. 96(2), 025503 (2006).
    [Crossref] [PubMed]
  32. B. Nowacki, H. Oh, C. Zanlorenzi, H. Jee, A. Baev, P. N. Prasad, and L. Akcelrud, “Design and synthesis of polymers for chiral photonics,” Macromolecules 46(18), 7158–7165 (2013).
    [Crossref]
  33. G. J. Lee, J. Park, E. Kim, Y. Lee, K. Kim, H. Cheong, C. Yoon, Y. D. Son, and J. Jang, “Microstructure of femtosecond laser-induced grating in amorphous silicon,” Opt. Express 13(17), 6445–6453 (2005).
    [Crossref] [PubMed]
  34. D. McBranch, I. H. Campbell, D. L. Smith, and J. P. Ferraris, “Optical determination of chain orientation in electroluminescent polymer films,” Appl. Phys. Lett. 66(10), 1175–1177 (1995).
    [Crossref]
  35. P. L. Stiles, J. A. Dieringer, N. C. Shah, and R. P. Van Duyne, “Surface-enhanced Raman spectroscopy,” Annu. Rev. Anal. Chem. (Palo Alto, Calif.) 1(1), 601–626 (2008).
    [Crossref] [PubMed]
  36. A. A. Kolomenskii, P. D. Gershon, and H. A. Schuessler, “Surface-plasmon resonance spectrometry and characterization of absorbing liquids,” Appl. Opt. 39(19), 3314–3320 (2000).
    [Crossref] [PubMed]
  37. W. P. Chen and J. M. Chen, “Use of surface plasma waves for determination of the thickness and optical constants of thin metallic films,” J. Opt. Soc. Am. 71(2), 189–191 (1981).
    [Crossref]
  38. M. E. Caldwell and E. M. Yeatman, “Surface-plasmon spatial light modulators based on liquid crystal,” Appl. Opt. 31(20), 3880–3891 (1992).
    [Crossref] [PubMed]
  39. I. Abdulhalim, “Surface plasmon TE and TM waves at the anisotropic film–metal interface,” J. Opt. A, Pure Appl. Opt. 11(1), 015002 (2009).
    [Crossref]

2015 (1)

M. Liu, L. Zhang, and T. Wang, “Supramolecular chirality in self-assembled systems,” Chem. Rev. 115(15), 7304–7397 (2015).
[Crossref] [PubMed]

2014 (3)

M. J. Cho, S. J. Kim, S. H. Yoon, J. Shin, T. R. Hong, H. J. Kim, Y. H. Son, J. S. Kang, H. A. Um, T. W. Lee, J. K. Bin, B. S. Lee, J. H. Yang, G. S. Chae, J. H. Kwon, and D. H. Choi, “New bipolar host materials for realizing blue phosphorescent organic light-emitting diodes with high efficiency at 1000 cd/m2.,” ACS Appl. Mater. Interfaces 6(22), 19808–19815 (2014).
[Crossref] [PubMed]

H. S. Oh, G. S. He, W. C. Law, A. Baev, H. Jee, X. Liu, A. Urbas, C. W. Lee, B. L. Choi, M. T. Swihart, and P. N. Prasad, “Manipulating nanoscale interactions in a polymer nanocomposite for chiral control of linear and nonlinear optical functions,” Adv. Mater. 26(10), 1607–1611 (2014).
[Crossref] [PubMed]

S. Guha, M. Knaapila, D. Moghe, Z. Konopkova, M. Torkkeli, M. Fritsch, and U. Scherf, “Persistence of nematic liquid crystalline phase in a polyfluorene‐based organic semiconductor: A high pressure study,” J. Polym. Sci., B, Polym. Phys. 52(15), 1014–1023 (2014).
[Crossref]

2013 (2)

G. S. He, M. J. Cho, W. J. Kim, A. Baev, A. Urbas, and P. N. Prasad, “Polarimetric z-scan study of nonlinear chiroptic properties of chiral polyfluorene,” Adv. Opt. Mater. 1(10), 763–767 (2013).
[Crossref]

B. Nowacki, H. Oh, C. Zanlorenzi, H. Jee, A. Baev, P. N. Prasad, and L. Akcelrud, “Design and synthesis of polymers for chiral photonics,” Macromolecules 46(18), 7158–7165 (2013).
[Crossref]

2011 (1)

M. Savoini, P. Biagioni, S. C. J. Meskers, L. Duo, B. Hecht, and M. Finazzi, “Spontaneous formation of left-and right-handed cholesterically ordered domains in an enantiopure chiral polyfluorene film,” J. Phys. Chem. Lett. 2(12), 1359–1362 (2011).
[Crossref]

2010 (1)

H. S. Oh, S. Liu, H. Jee, A. Baev, M. T. Swihart, and P. N. Prasad, “Chiral poly(fluorene-alt-benzothiadiazole) (PFBT) and nanocomposites with gold nanoparticles: plasmonically and structurally enhanced chirality,” J. Am. Chem. Soc. 132(49), 17346–17348 (2010).
[Crossref] [PubMed]

2009 (3)

S. J. George, T. F. A. de Greef, R. Bovee, J. L. J. van Dongen, A. P. H. J. Schenning, and E. W. Meijer, “Photodimerization processes in self-assembled chiral oligo(p-phenylenevinylene) bolaamphiphiles,” Chem. Asian J. 4(6), 910–917 (2009).
[Crossref] [PubMed]

G. Lakhwani, J. Gielen, M. Kemerink, P. C. M. Christianen, R. A. J. Janssen, and S. C. J. Meskers, “Intensive chiroptical properties of chiral polyfluorenes associated with fibril formation,” J. Phys. Chem. B 113(43), 14047–14051 (2009).
[Crossref] [PubMed]

I. Abdulhalim, “Surface plasmon TE and TM waves at the anisotropic film–metal interface,” J. Opt. A, Pure Appl. Opt. 11(1), 015002 (2009).
[Crossref]

2008 (3)

P. L. Stiles, J. A. Dieringer, N. C. Shah, and R. P. Van Duyne, “Surface-enhanced Raman spectroscopy,” Annu. Rev. Anal. Chem. (Palo Alto, Calif.) 1(1), 601–626 (2008).
[Crossref] [PubMed]

R. Abbel, A. P. H. J. Schenning, and E. W. Meijer, “Molecular weight optimum in the mesoscopic order of chiral fluorene copolymer films,” Macromolecules 41(20), 7497–7504 (2008).
[Crossref]

W. C. Tsoi and D. G. Lidzey, “Raman spectroscopy of fluorene oligomers in the α-, β-and γ-phases,” J. Phys. Condens. Matter 20(12), 125213 (2008).
[Crossref]

2007 (3)

C. Volz, M. Arif, and S. Guha, “Conformations in dioctyl substituted polyfluorene: A combined theoretical and experimental Raman scattering study,” J. Chem. Phys. 126(6), 064905 (2007).
[Crossref] [PubMed]

J. C. Yan, X. Cheng, Q. L. Zhou, and J. Pei, “Chiral polyfluorene derivatives: Synthesis, chiroptical properties, and investigation of the structure-property relationships,” Macromolecules 40(4), 832–839 (2007).
[Crossref]

A. R. A. Palmans and E. W. Meijer, “Amplification of chirality in dynamic supramolecular aggregates,” Angew. Chem. Int. Ed. Engl. 46(47), 8948–8968 (2007).
[Crossref] [PubMed]

2006 (1)

M. Arif, C. Volz, and S. Guha, “Chain morphologies in semicrystalline polyfluorene: Evidence from Raman scattering,” Phys. Rev. Lett. 96(2), 025503 (2006).
[Crossref] [PubMed]

2005 (3)

W. Chunwaschirasiri, B. Tanto, D. L. Huber, and M. J. Winokur, “Chain conformations and photoluminescence of poly(di-n-octylfluorene),” Phys. Rev. Lett. 94(10), 107402 (2005).
[Crossref] [PubMed]

G. J. Lee, J. Park, E. Kim, Y. Lee, K. Kim, H. Cheong, C. Yoon, Y. D. Son, and J. Jang, “Microstructure of femtosecond laser-induced grating in amorphous silicon,” Opt. Express 13(17), 6445–6453 (2005).
[Crossref] [PubMed]

M. Campoy-Quiles, G. Heliotis, R. Xia, M. Ariu, M. Pintani, P. Etchegoin, and D. D. C. Bradley, “Ellipsometric characterization of the optical constants of polyfluorene gain media,” Adv. Funct. Mater. 15(6), 925–933 (2005).
[Crossref]

2004 (1)

J. S. Kim, P. K. H. Ho, C. E. Murphy, and R. H. Friend, “Phase separation in polyfluorene-based conjugated polymer blends: Lateral and vertical analysis of blend spin-cast thin films,” Macromolecules 37(8), 2861–2871 (2004).
[Crossref]

2002 (4)

U. Scherf and E. J. List, “Semiconducting polyfluorenes–Towards reliable structure–property relationships,” Adv. Mater. 14(7), 477–487 (2002).
[Crossref]

M. Oda, H. G. Nothofer, U. Scherf, I. V. Sunjic, D. Richter, W. Regenstein, and D. Neher, “Chiroptical properties of chiral substituted polyfluorenes,” Macromolecules 35(18), 6792–6798 (2002).
[Crossref]

H. S. Kang, K. H. Kim, M. S. Kim, K. T. Park, K. M. Kim, T. H. Lee, C. Y. Lee, J. Joo, D. W. Lee, Y. R. Hong, K. Kim, G. J. Lee, and J. I. Jin, “Electrical characteristics of light-emitting diode based on poly(p-phenylenevinylene) derivatives: CzEH-PPV and OxdEH-PPV,” Synth. Met. 130(3), 279–283 (2002).
[Crossref]

G. J. Lee, K. Kim, and J. I. Jin, “Mechanism of one-and two-photon absorption induced photoluminescence in PPV type, electroluminescent polymer,” Opt. Commun. 203(1-2), 151–157 (2002).
[Crossref]

2001 (1)

T. Miteva, A. Meisel, W. Knoll, H. G. Nothofer, U. Scherf, D. C. Muller, and D. Neher, “Improving the performance of polyfluorene‐based organic light‐emitting diodes via end‐capping,” Adv. Mater. 13(8), 565–570 (2001).
[Crossref]

2000 (4)

M. Gross, D. C. Muller, H. G. Nothofer, U. Scherf, D. Neher, C. Brauchle, and K. Meerholz, “Improving the performance of doped π-conjugated polymers for use in organic light-emitting diodes,” Nature 405(6787), 661–665 (2000).
[Crossref] [PubMed]

M. Oda, H. G. Nothofer, U. Scherf, S. C. J. Meskers, and D. Neher, “Circularly polarized electroluminescence from liquid‐crystalline chiral polyfluorenes,” Adv. Mater. 12(5), 362–365 (2000).
[Crossref]

M. T. Bernius, M. Inbasekaran, J. O’Brien, and W. Wu, “Progress with light-emitting polymers,” Adv. Mater. 12(23), 1737–1750 (2000).
[Crossref]

A. A. Kolomenskii, P. D. Gershon, and H. A. Schuessler, “Surface-plasmon resonance spectrometry and characterization of absorbing liquids,” Appl. Opt. 39(19), 3314–3320 (2000).
[Crossref] [PubMed]

1999 (3)

M. Grell, D. D. C. Bradley, G. Ungar, J. Hill, and K. S. Whitehead, “Interplay of physical structure and photophysics for a liquid crystalline polyfluorene,” Macromolecules 32(18), 5810–5817 (1999).
[Crossref]

R. Fiesel, C. E. Halkyard, M. E. Rampey, L. Kloppenburg, S. L. Studer-Martinez, U. Scherf, and U. H. F. Bunz, “Aggregation and chiroptical behavior of a high molecular weight chirally substituted dialkylpoly(p-phenyleneethynylene),” Macromol. Rapid Commun. 20(3), 107–111 (1999).
[Crossref]

M. Grell and D. D. C. Bradley, “Polarized luminescence from oriented molecular materials,” Adv. Mater. 11(11), 895–905 (1999).
[Crossref]

1998 (1)

R. Fiesel and U. Scherf, “Aggregation-induced CD effects in chiral poly(2,5-dialkoxy-1,4-phenylene)s,” Acta Polym. 49(8), 445–449 (1998).
[Crossref]

1995 (2)

M. M. Bournan and E. W. Meijer, “Stereomutation in optically active regioregular polythiophenes,” Adv. Mater. 7(4), 385–387 (1995).
[Crossref]

D. McBranch, I. H. Campbell, D. L. Smith, and J. P. Ferraris, “Optical determination of chain orientation in electroluminescent polymer films,” Appl. Phys. Lett. 66(10), 1175–1177 (1995).
[Crossref]

1992 (1)

1981 (1)

Abbel, R.

R. Abbel, A. P. H. J. Schenning, and E. W. Meijer, “Molecular weight optimum in the mesoscopic order of chiral fluorene copolymer films,” Macromolecules 41(20), 7497–7504 (2008).
[Crossref]

Abdulhalim, I.

I. Abdulhalim, “Surface plasmon TE and TM waves at the anisotropic film–metal interface,” J. Opt. A, Pure Appl. Opt. 11(1), 015002 (2009).
[Crossref]

Akcelrud, L.

B. Nowacki, H. Oh, C. Zanlorenzi, H. Jee, A. Baev, P. N. Prasad, and L. Akcelrud, “Design and synthesis of polymers for chiral photonics,” Macromolecules 46(18), 7158–7165 (2013).
[Crossref]

Arif, M.

C. Volz, M. Arif, and S. Guha, “Conformations in dioctyl substituted polyfluorene: A combined theoretical and experimental Raman scattering study,” J. Chem. Phys. 126(6), 064905 (2007).
[Crossref] [PubMed]

M. Arif, C. Volz, and S. Guha, “Chain morphologies in semicrystalline polyfluorene: Evidence from Raman scattering,” Phys. Rev. Lett. 96(2), 025503 (2006).
[Crossref] [PubMed]

Ariu, M.

M. Campoy-Quiles, G. Heliotis, R. Xia, M. Ariu, M. Pintani, P. Etchegoin, and D. D. C. Bradley, “Ellipsometric characterization of the optical constants of polyfluorene gain media,” Adv. Funct. Mater. 15(6), 925–933 (2005).
[Crossref]

Baev, A.

H. S. Oh, G. S. He, W. C. Law, A. Baev, H. Jee, X. Liu, A. Urbas, C. W. Lee, B. L. Choi, M. T. Swihart, and P. N. Prasad, “Manipulating nanoscale interactions in a polymer nanocomposite for chiral control of linear and nonlinear optical functions,” Adv. Mater. 26(10), 1607–1611 (2014).
[Crossref] [PubMed]

G. S. He, M. J. Cho, W. J. Kim, A. Baev, A. Urbas, and P. N. Prasad, “Polarimetric z-scan study of nonlinear chiroptic properties of chiral polyfluorene,” Adv. Opt. Mater. 1(10), 763–767 (2013).
[Crossref]

B. Nowacki, H. Oh, C. Zanlorenzi, H. Jee, A. Baev, P. N. Prasad, and L. Akcelrud, “Design and synthesis of polymers for chiral photonics,” Macromolecules 46(18), 7158–7165 (2013).
[Crossref]

H. S. Oh, S. Liu, H. Jee, A. Baev, M. T. Swihart, and P. N. Prasad, “Chiral poly(fluorene-alt-benzothiadiazole) (PFBT) and nanocomposites with gold nanoparticles: plasmonically and structurally enhanced chirality,” J. Am. Chem. Soc. 132(49), 17346–17348 (2010).
[Crossref] [PubMed]

Bernius, M. T.

M. T. Bernius, M. Inbasekaran, J. O’Brien, and W. Wu, “Progress with light-emitting polymers,” Adv. Mater. 12(23), 1737–1750 (2000).
[Crossref]

Biagioni, P.

M. Savoini, P. Biagioni, S. C. J. Meskers, L. Duo, B. Hecht, and M. Finazzi, “Spontaneous formation of left-and right-handed cholesterically ordered domains in an enantiopure chiral polyfluorene film,” J. Phys. Chem. Lett. 2(12), 1359–1362 (2011).
[Crossref]

Bin, J. K.

M. J. Cho, S. J. Kim, S. H. Yoon, J. Shin, T. R. Hong, H. J. Kim, Y. H. Son, J. S. Kang, H. A. Um, T. W. Lee, J. K. Bin, B. S. Lee, J. H. Yang, G. S. Chae, J. H. Kwon, and D. H. Choi, “New bipolar host materials for realizing blue phosphorescent organic light-emitting diodes with high efficiency at 1000 cd/m2.,” ACS Appl. Mater. Interfaces 6(22), 19808–19815 (2014).
[Crossref] [PubMed]

Bournan, M. M.

M. M. Bournan and E. W. Meijer, “Stereomutation in optically active regioregular polythiophenes,” Adv. Mater. 7(4), 385–387 (1995).
[Crossref]

Bovee, R.

S. J. George, T. F. A. de Greef, R. Bovee, J. L. J. van Dongen, A. P. H. J. Schenning, and E. W. Meijer, “Photodimerization processes in self-assembled chiral oligo(p-phenylenevinylene) bolaamphiphiles,” Chem. Asian J. 4(6), 910–917 (2009).
[Crossref] [PubMed]

Bradley, D. D. C.

M. Campoy-Quiles, G. Heliotis, R. Xia, M. Ariu, M. Pintani, P. Etchegoin, and D. D. C. Bradley, “Ellipsometric characterization of the optical constants of polyfluorene gain media,” Adv. Funct. Mater. 15(6), 925–933 (2005).
[Crossref]

M. Grell and D. D. C. Bradley, “Polarized luminescence from oriented molecular materials,” Adv. Mater. 11(11), 895–905 (1999).
[Crossref]

M. Grell, D. D. C. Bradley, G. Ungar, J. Hill, and K. S. Whitehead, “Interplay of physical structure and photophysics for a liquid crystalline polyfluorene,” Macromolecules 32(18), 5810–5817 (1999).
[Crossref]

Brauchle, C.

M. Gross, D. C. Muller, H. G. Nothofer, U. Scherf, D. Neher, C. Brauchle, and K. Meerholz, “Improving the performance of doped π-conjugated polymers for use in organic light-emitting diodes,” Nature 405(6787), 661–665 (2000).
[Crossref] [PubMed]

Bunz, U. H. F.

R. Fiesel, C. E. Halkyard, M. E. Rampey, L. Kloppenburg, S. L. Studer-Martinez, U. Scherf, and U. H. F. Bunz, “Aggregation and chiroptical behavior of a high molecular weight chirally substituted dialkylpoly(p-phenyleneethynylene),” Macromol. Rapid Commun. 20(3), 107–111 (1999).
[Crossref]

Caldwell, M. E.

Campbell, I. H.

D. McBranch, I. H. Campbell, D. L. Smith, and J. P. Ferraris, “Optical determination of chain orientation in electroluminescent polymer films,” Appl. Phys. Lett. 66(10), 1175–1177 (1995).
[Crossref]

Campoy-Quiles, M.

M. Campoy-Quiles, G. Heliotis, R. Xia, M. Ariu, M. Pintani, P. Etchegoin, and D. D. C. Bradley, “Ellipsometric characterization of the optical constants of polyfluorene gain media,” Adv. Funct. Mater. 15(6), 925–933 (2005).
[Crossref]

Chae, G. S.

M. J. Cho, S. J. Kim, S. H. Yoon, J. Shin, T. R. Hong, H. J. Kim, Y. H. Son, J. S. Kang, H. A. Um, T. W. Lee, J. K. Bin, B. S. Lee, J. H. Yang, G. S. Chae, J. H. Kwon, and D. H. Choi, “New bipolar host materials for realizing blue phosphorescent organic light-emitting diodes with high efficiency at 1000 cd/m2.,” ACS Appl. Mater. Interfaces 6(22), 19808–19815 (2014).
[Crossref] [PubMed]

Chen, J. M.

Chen, W. P.

Cheng, X.

J. C. Yan, X. Cheng, Q. L. Zhou, and J. Pei, “Chiral polyfluorene derivatives: Synthesis, chiroptical properties, and investigation of the structure-property relationships,” Macromolecules 40(4), 832–839 (2007).
[Crossref]

Cheong, H.

Cho, M. J.

M. J. Cho, S. J. Kim, S. H. Yoon, J. Shin, T. R. Hong, H. J. Kim, Y. H. Son, J. S. Kang, H. A. Um, T. W. Lee, J. K. Bin, B. S. Lee, J. H. Yang, G. S. Chae, J. H. Kwon, and D. H. Choi, “New bipolar host materials for realizing blue phosphorescent organic light-emitting diodes with high efficiency at 1000 cd/m2.,” ACS Appl. Mater. Interfaces 6(22), 19808–19815 (2014).
[Crossref] [PubMed]

G. S. He, M. J. Cho, W. J. Kim, A. Baev, A. Urbas, and P. N. Prasad, “Polarimetric z-scan study of nonlinear chiroptic properties of chiral polyfluorene,” Adv. Opt. Mater. 1(10), 763–767 (2013).
[Crossref]

Choi, B. L.

H. S. Oh, G. S. He, W. C. Law, A. Baev, H. Jee, X. Liu, A. Urbas, C. W. Lee, B. L. Choi, M. T. Swihart, and P. N. Prasad, “Manipulating nanoscale interactions in a polymer nanocomposite for chiral control of linear and nonlinear optical functions,” Adv. Mater. 26(10), 1607–1611 (2014).
[Crossref] [PubMed]

Choi, D. H.

M. J. Cho, S. J. Kim, S. H. Yoon, J. Shin, T. R. Hong, H. J. Kim, Y. H. Son, J. S. Kang, H. A. Um, T. W. Lee, J. K. Bin, B. S. Lee, J. H. Yang, G. S. Chae, J. H. Kwon, and D. H. Choi, “New bipolar host materials for realizing blue phosphorescent organic light-emitting diodes with high efficiency at 1000 cd/m2.,” ACS Appl. Mater. Interfaces 6(22), 19808–19815 (2014).
[Crossref] [PubMed]

Christianen, P. C. M.

G. Lakhwani, J. Gielen, M. Kemerink, P. C. M. Christianen, R. A. J. Janssen, and S. C. J. Meskers, “Intensive chiroptical properties of chiral polyfluorenes associated with fibril formation,” J. Phys. Chem. B 113(43), 14047–14051 (2009).
[Crossref] [PubMed]

Chunwaschirasiri, W.

W. Chunwaschirasiri, B. Tanto, D. L. Huber, and M. J. Winokur, “Chain conformations and photoluminescence of poly(di-n-octylfluorene),” Phys. Rev. Lett. 94(10), 107402 (2005).
[Crossref] [PubMed]

de Greef, T. F. A.

S. J. George, T. F. A. de Greef, R. Bovee, J. L. J. van Dongen, A. P. H. J. Schenning, and E. W. Meijer, “Photodimerization processes in self-assembled chiral oligo(p-phenylenevinylene) bolaamphiphiles,” Chem. Asian J. 4(6), 910–917 (2009).
[Crossref] [PubMed]

Dieringer, J. A.

P. L. Stiles, J. A. Dieringer, N. C. Shah, and R. P. Van Duyne, “Surface-enhanced Raman spectroscopy,” Annu. Rev. Anal. Chem. (Palo Alto, Calif.) 1(1), 601–626 (2008).
[Crossref] [PubMed]

Duo, L.

M. Savoini, P. Biagioni, S. C. J. Meskers, L. Duo, B. Hecht, and M. Finazzi, “Spontaneous formation of left-and right-handed cholesterically ordered domains in an enantiopure chiral polyfluorene film,” J. Phys. Chem. Lett. 2(12), 1359–1362 (2011).
[Crossref]

Etchegoin, P.

M. Campoy-Quiles, G. Heliotis, R. Xia, M. Ariu, M. Pintani, P. Etchegoin, and D. D. C. Bradley, “Ellipsometric characterization of the optical constants of polyfluorene gain media,” Adv. Funct. Mater. 15(6), 925–933 (2005).
[Crossref]

Ferraris, J. P.

D. McBranch, I. H. Campbell, D. L. Smith, and J. P. Ferraris, “Optical determination of chain orientation in electroluminescent polymer films,” Appl. Phys. Lett. 66(10), 1175–1177 (1995).
[Crossref]

Fiesel, R.

R. Fiesel, C. E. Halkyard, M. E. Rampey, L. Kloppenburg, S. L. Studer-Martinez, U. Scherf, and U. H. F. Bunz, “Aggregation and chiroptical behavior of a high molecular weight chirally substituted dialkylpoly(p-phenyleneethynylene),” Macromol. Rapid Commun. 20(3), 107–111 (1999).
[Crossref]

R. Fiesel and U. Scherf, “Aggregation-induced CD effects in chiral poly(2,5-dialkoxy-1,4-phenylene)s,” Acta Polym. 49(8), 445–449 (1998).
[Crossref]

Finazzi, M.

M. Savoini, P. Biagioni, S. C. J. Meskers, L. Duo, B. Hecht, and M. Finazzi, “Spontaneous formation of left-and right-handed cholesterically ordered domains in an enantiopure chiral polyfluorene film,” J. Phys. Chem. Lett. 2(12), 1359–1362 (2011).
[Crossref]

Friend, R. H.

J. S. Kim, P. K. H. Ho, C. E. Murphy, and R. H. Friend, “Phase separation in polyfluorene-based conjugated polymer blends: Lateral and vertical analysis of blend spin-cast thin films,” Macromolecules 37(8), 2861–2871 (2004).
[Crossref]

Fritsch, M.

S. Guha, M. Knaapila, D. Moghe, Z. Konopkova, M. Torkkeli, M. Fritsch, and U. Scherf, “Persistence of nematic liquid crystalline phase in a polyfluorene‐based organic semiconductor: A high pressure study,” J. Polym. Sci., B, Polym. Phys. 52(15), 1014–1023 (2014).
[Crossref]

George, S. J.

S. J. George, T. F. A. de Greef, R. Bovee, J. L. J. van Dongen, A. P. H. J. Schenning, and E. W. Meijer, “Photodimerization processes in self-assembled chiral oligo(p-phenylenevinylene) bolaamphiphiles,” Chem. Asian J. 4(6), 910–917 (2009).
[Crossref] [PubMed]

Gershon, P. D.

Gielen, J.

G. Lakhwani, J. Gielen, M. Kemerink, P. C. M. Christianen, R. A. J. Janssen, and S. C. J. Meskers, “Intensive chiroptical properties of chiral polyfluorenes associated with fibril formation,” J. Phys. Chem. B 113(43), 14047–14051 (2009).
[Crossref] [PubMed]

Grell, M.

M. Grell, D. D. C. Bradley, G. Ungar, J. Hill, and K. S. Whitehead, “Interplay of physical structure and photophysics for a liquid crystalline polyfluorene,” Macromolecules 32(18), 5810–5817 (1999).
[Crossref]

M. Grell and D. D. C. Bradley, “Polarized luminescence from oriented molecular materials,” Adv. Mater. 11(11), 895–905 (1999).
[Crossref]

Gross, M.

M. Gross, D. C. Muller, H. G. Nothofer, U. Scherf, D. Neher, C. Brauchle, and K. Meerholz, “Improving the performance of doped π-conjugated polymers for use in organic light-emitting diodes,” Nature 405(6787), 661–665 (2000).
[Crossref] [PubMed]

Guha, S.

S. Guha, M. Knaapila, D. Moghe, Z. Konopkova, M. Torkkeli, M. Fritsch, and U. Scherf, “Persistence of nematic liquid crystalline phase in a polyfluorene‐based organic semiconductor: A high pressure study,” J. Polym. Sci., B, Polym. Phys. 52(15), 1014–1023 (2014).
[Crossref]

C. Volz, M. Arif, and S. Guha, “Conformations in dioctyl substituted polyfluorene: A combined theoretical and experimental Raman scattering study,” J. Chem. Phys. 126(6), 064905 (2007).
[Crossref] [PubMed]

M. Arif, C. Volz, and S. Guha, “Chain morphologies in semicrystalline polyfluorene: Evidence from Raman scattering,” Phys. Rev. Lett. 96(2), 025503 (2006).
[Crossref] [PubMed]

Halkyard, C. E.

R. Fiesel, C. E. Halkyard, M. E. Rampey, L. Kloppenburg, S. L. Studer-Martinez, U. Scherf, and U. H. F. Bunz, “Aggregation and chiroptical behavior of a high molecular weight chirally substituted dialkylpoly(p-phenyleneethynylene),” Macromol. Rapid Commun. 20(3), 107–111 (1999).
[Crossref]

He, G. S.

H. S. Oh, G. S. He, W. C. Law, A. Baev, H. Jee, X. Liu, A. Urbas, C. W. Lee, B. L. Choi, M. T. Swihart, and P. N. Prasad, “Manipulating nanoscale interactions in a polymer nanocomposite for chiral control of linear and nonlinear optical functions,” Adv. Mater. 26(10), 1607–1611 (2014).
[Crossref] [PubMed]

G. S. He, M. J. Cho, W. J. Kim, A. Baev, A. Urbas, and P. N. Prasad, “Polarimetric z-scan study of nonlinear chiroptic properties of chiral polyfluorene,” Adv. Opt. Mater. 1(10), 763–767 (2013).
[Crossref]

Hecht, B.

M. Savoini, P. Biagioni, S. C. J. Meskers, L. Duo, B. Hecht, and M. Finazzi, “Spontaneous formation of left-and right-handed cholesterically ordered domains in an enantiopure chiral polyfluorene film,” J. Phys. Chem. Lett. 2(12), 1359–1362 (2011).
[Crossref]

Heliotis, G.

M. Campoy-Quiles, G. Heliotis, R. Xia, M. Ariu, M. Pintani, P. Etchegoin, and D. D. C. Bradley, “Ellipsometric characterization of the optical constants of polyfluorene gain media,” Adv. Funct. Mater. 15(6), 925–933 (2005).
[Crossref]

Hill, J.

M. Grell, D. D. C. Bradley, G. Ungar, J. Hill, and K. S. Whitehead, “Interplay of physical structure and photophysics for a liquid crystalline polyfluorene,” Macromolecules 32(18), 5810–5817 (1999).
[Crossref]

Ho, P. K. H.

J. S. Kim, P. K. H. Ho, C. E. Murphy, and R. H. Friend, “Phase separation in polyfluorene-based conjugated polymer blends: Lateral and vertical analysis of blend spin-cast thin films,” Macromolecules 37(8), 2861–2871 (2004).
[Crossref]

Hong, T. R.

M. J. Cho, S. J. Kim, S. H. Yoon, J. Shin, T. R. Hong, H. J. Kim, Y. H. Son, J. S. Kang, H. A. Um, T. W. Lee, J. K. Bin, B. S. Lee, J. H. Yang, G. S. Chae, J. H. Kwon, and D. H. Choi, “New bipolar host materials for realizing blue phosphorescent organic light-emitting diodes with high efficiency at 1000 cd/m2.,” ACS Appl. Mater. Interfaces 6(22), 19808–19815 (2014).
[Crossref] [PubMed]

Hong, Y. R.

H. S. Kang, K. H. Kim, M. S. Kim, K. T. Park, K. M. Kim, T. H. Lee, C. Y. Lee, J. Joo, D. W. Lee, Y. R. Hong, K. Kim, G. J. Lee, and J. I. Jin, “Electrical characteristics of light-emitting diode based on poly(p-phenylenevinylene) derivatives: CzEH-PPV and OxdEH-PPV,” Synth. Met. 130(3), 279–283 (2002).
[Crossref]

Huber, D. L.

W. Chunwaschirasiri, B. Tanto, D. L. Huber, and M. J. Winokur, “Chain conformations and photoluminescence of poly(di-n-octylfluorene),” Phys. Rev. Lett. 94(10), 107402 (2005).
[Crossref] [PubMed]

Inbasekaran, M.

M. T. Bernius, M. Inbasekaran, J. O’Brien, and W. Wu, “Progress with light-emitting polymers,” Adv. Mater. 12(23), 1737–1750 (2000).
[Crossref]

Jang, J.

Janssen, R. A. J.

G. Lakhwani, J. Gielen, M. Kemerink, P. C. M. Christianen, R. A. J. Janssen, and S. C. J. Meskers, “Intensive chiroptical properties of chiral polyfluorenes associated with fibril formation,” J. Phys. Chem. B 113(43), 14047–14051 (2009).
[Crossref] [PubMed]

Jee, H.

H. S. Oh, G. S. He, W. C. Law, A. Baev, H. Jee, X. Liu, A. Urbas, C. W. Lee, B. L. Choi, M. T. Swihart, and P. N. Prasad, “Manipulating nanoscale interactions in a polymer nanocomposite for chiral control of linear and nonlinear optical functions,” Adv. Mater. 26(10), 1607–1611 (2014).
[Crossref] [PubMed]

B. Nowacki, H. Oh, C. Zanlorenzi, H. Jee, A. Baev, P. N. Prasad, and L. Akcelrud, “Design and synthesis of polymers for chiral photonics,” Macromolecules 46(18), 7158–7165 (2013).
[Crossref]

H. S. Oh, S. Liu, H. Jee, A. Baev, M. T. Swihart, and P. N. Prasad, “Chiral poly(fluorene-alt-benzothiadiazole) (PFBT) and nanocomposites with gold nanoparticles: plasmonically and structurally enhanced chirality,” J. Am. Chem. Soc. 132(49), 17346–17348 (2010).
[Crossref] [PubMed]

Jin, J. I.

H. S. Kang, K. H. Kim, M. S. Kim, K. T. Park, K. M. Kim, T. H. Lee, C. Y. Lee, J. Joo, D. W. Lee, Y. R. Hong, K. Kim, G. J. Lee, and J. I. Jin, “Electrical characteristics of light-emitting diode based on poly(p-phenylenevinylene) derivatives: CzEH-PPV and OxdEH-PPV,” Synth. Met. 130(3), 279–283 (2002).
[Crossref]

G. J. Lee, K. Kim, and J. I. Jin, “Mechanism of one-and two-photon absorption induced photoluminescence in PPV type, electroluminescent polymer,” Opt. Commun. 203(1-2), 151–157 (2002).
[Crossref]

Joo, J.

H. S. Kang, K. H. Kim, M. S. Kim, K. T. Park, K. M. Kim, T. H. Lee, C. Y. Lee, J. Joo, D. W. Lee, Y. R. Hong, K. Kim, G. J. Lee, and J. I. Jin, “Electrical characteristics of light-emitting diode based on poly(p-phenylenevinylene) derivatives: CzEH-PPV and OxdEH-PPV,” Synth. Met. 130(3), 279–283 (2002).
[Crossref]

Kang, H. S.

H. S. Kang, K. H. Kim, M. S. Kim, K. T. Park, K. M. Kim, T. H. Lee, C. Y. Lee, J. Joo, D. W. Lee, Y. R. Hong, K. Kim, G. J. Lee, and J. I. Jin, “Electrical characteristics of light-emitting diode based on poly(p-phenylenevinylene) derivatives: CzEH-PPV and OxdEH-PPV,” Synth. Met. 130(3), 279–283 (2002).
[Crossref]

Kang, J. S.

M. J. Cho, S. J. Kim, S. H. Yoon, J. Shin, T. R. Hong, H. J. Kim, Y. H. Son, J. S. Kang, H. A. Um, T. W. Lee, J. K. Bin, B. S. Lee, J. H. Yang, G. S. Chae, J. H. Kwon, and D. H. Choi, “New bipolar host materials for realizing blue phosphorescent organic light-emitting diodes with high efficiency at 1000 cd/m2.,” ACS Appl. Mater. Interfaces 6(22), 19808–19815 (2014).
[Crossref] [PubMed]

Kemerink, M.

G. Lakhwani, J. Gielen, M. Kemerink, P. C. M. Christianen, R. A. J. Janssen, and S. C. J. Meskers, “Intensive chiroptical properties of chiral polyfluorenes associated with fibril formation,” J. Phys. Chem. B 113(43), 14047–14051 (2009).
[Crossref] [PubMed]

Kim, E.

Kim, H. J.

M. J. Cho, S. J. Kim, S. H. Yoon, J. Shin, T. R. Hong, H. J. Kim, Y. H. Son, J. S. Kang, H. A. Um, T. W. Lee, J. K. Bin, B. S. Lee, J. H. Yang, G. S. Chae, J. H. Kwon, and D. H. Choi, “New bipolar host materials for realizing blue phosphorescent organic light-emitting diodes with high efficiency at 1000 cd/m2.,” ACS Appl. Mater. Interfaces 6(22), 19808–19815 (2014).
[Crossref] [PubMed]

Kim, J. S.

J. S. Kim, P. K. H. Ho, C. E. Murphy, and R. H. Friend, “Phase separation in polyfluorene-based conjugated polymer blends: Lateral and vertical analysis of blend spin-cast thin films,” Macromolecules 37(8), 2861–2871 (2004).
[Crossref]

Kim, K.

G. J. Lee, J. Park, E. Kim, Y. Lee, K. Kim, H. Cheong, C. Yoon, Y. D. Son, and J. Jang, “Microstructure of femtosecond laser-induced grating in amorphous silicon,” Opt. Express 13(17), 6445–6453 (2005).
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G. J. Lee, K. Kim, and J. I. Jin, “Mechanism of one-and two-photon absorption induced photoluminescence in PPV type, electroluminescent polymer,” Opt. Commun. 203(1-2), 151–157 (2002).
[Crossref]

H. S. Kang, K. H. Kim, M. S. Kim, K. T. Park, K. M. Kim, T. H. Lee, C. Y. Lee, J. Joo, D. W. Lee, Y. R. Hong, K. Kim, G. J. Lee, and J. I. Jin, “Electrical characteristics of light-emitting diode based on poly(p-phenylenevinylene) derivatives: CzEH-PPV and OxdEH-PPV,” Synth. Met. 130(3), 279–283 (2002).
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H. S. Kang, K. H. Kim, M. S. Kim, K. T. Park, K. M. Kim, T. H. Lee, C. Y. Lee, J. Joo, D. W. Lee, Y. R. Hong, K. Kim, G. J. Lee, and J. I. Jin, “Electrical characteristics of light-emitting diode based on poly(p-phenylenevinylene) derivatives: CzEH-PPV and OxdEH-PPV,” Synth. Met. 130(3), 279–283 (2002).
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H. S. Kang, K. H. Kim, M. S. Kim, K. T. Park, K. M. Kim, T. H. Lee, C. Y. Lee, J. Joo, D. W. Lee, Y. R. Hong, K. Kim, G. J. Lee, and J. I. Jin, “Electrical characteristics of light-emitting diode based on poly(p-phenylenevinylene) derivatives: CzEH-PPV and OxdEH-PPV,” Synth. Met. 130(3), 279–283 (2002).
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H. S. Kang, K. H. Kim, M. S. Kim, K. T. Park, K. M. Kim, T. H. Lee, C. Y. Lee, J. Joo, D. W. Lee, Y. R. Hong, K. Kim, G. J. Lee, and J. I. Jin, “Electrical characteristics of light-emitting diode based on poly(p-phenylenevinylene) derivatives: CzEH-PPV and OxdEH-PPV,” Synth. Met. 130(3), 279–283 (2002).
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M. J. Cho, S. J. Kim, S. H. Yoon, J. Shin, T. R. Hong, H. J. Kim, Y. H. Son, J. S. Kang, H. A. Um, T. W. Lee, J. K. Bin, B. S. Lee, J. H. Yang, G. S. Chae, J. H. Kwon, and D. H. Choi, “New bipolar host materials for realizing blue phosphorescent organic light-emitting diodes with high efficiency at 1000 cd/m2.,” ACS Appl. Mater. Interfaces 6(22), 19808–19815 (2014).
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G. S. He, M. J. Cho, W. J. Kim, A. Baev, A. Urbas, and P. N. Prasad, “Polarimetric z-scan study of nonlinear chiroptic properties of chiral polyfluorene,” Adv. Opt. Mater. 1(10), 763–767 (2013).
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R. Fiesel, C. E. Halkyard, M. E. Rampey, L. Kloppenburg, S. L. Studer-Martinez, U. Scherf, and U. H. F. Bunz, “Aggregation and chiroptical behavior of a high molecular weight chirally substituted dialkylpoly(p-phenyleneethynylene),” Macromol. Rapid Commun. 20(3), 107–111 (1999).
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S. Guha, M. Knaapila, D. Moghe, Z. Konopkova, M. Torkkeli, M. Fritsch, and U. Scherf, “Persistence of nematic liquid crystalline phase in a polyfluorene‐based organic semiconductor: A high pressure study,” J. Polym. Sci., B, Polym. Phys. 52(15), 1014–1023 (2014).
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T. Miteva, A. Meisel, W. Knoll, H. G. Nothofer, U. Scherf, D. C. Muller, and D. Neher, “Improving the performance of polyfluorene‐based organic light‐emitting diodes via end‐capping,” Adv. Mater. 13(8), 565–570 (2001).
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Konopkova, Z.

S. Guha, M. Knaapila, D. Moghe, Z. Konopkova, M. Torkkeli, M. Fritsch, and U. Scherf, “Persistence of nematic liquid crystalline phase in a polyfluorene‐based organic semiconductor: A high pressure study,” J. Polym. Sci., B, Polym. Phys. 52(15), 1014–1023 (2014).
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M. J. Cho, S. J. Kim, S. H. Yoon, J. Shin, T. R. Hong, H. J. Kim, Y. H. Son, J. S. Kang, H. A. Um, T. W. Lee, J. K. Bin, B. S. Lee, J. H. Yang, G. S. Chae, J. H. Kwon, and D. H. Choi, “New bipolar host materials for realizing blue phosphorescent organic light-emitting diodes with high efficiency at 1000 cd/m2.,” ACS Appl. Mater. Interfaces 6(22), 19808–19815 (2014).
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G. Lakhwani, J. Gielen, M. Kemerink, P. C. M. Christianen, R. A. J. Janssen, and S. C. J. Meskers, “Intensive chiroptical properties of chiral polyfluorenes associated with fibril formation,” J. Phys. Chem. B 113(43), 14047–14051 (2009).
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H. S. Oh, G. S. He, W. C. Law, A. Baev, H. Jee, X. Liu, A. Urbas, C. W. Lee, B. L. Choi, M. T. Swihart, and P. N. Prasad, “Manipulating nanoscale interactions in a polymer nanocomposite for chiral control of linear and nonlinear optical functions,” Adv. Mater. 26(10), 1607–1611 (2014).
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M. J. Cho, S. J. Kim, S. H. Yoon, J. Shin, T. R. Hong, H. J. Kim, Y. H. Son, J. S. Kang, H. A. Um, T. W. Lee, J. K. Bin, B. S. Lee, J. H. Yang, G. S. Chae, J. H. Kwon, and D. H. Choi, “New bipolar host materials for realizing blue phosphorescent organic light-emitting diodes with high efficiency at 1000 cd/m2.,” ACS Appl. Mater. Interfaces 6(22), 19808–19815 (2014).
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H. S. Oh, G. S. He, W. C. Law, A. Baev, H. Jee, X. Liu, A. Urbas, C. W. Lee, B. L. Choi, M. T. Swihart, and P. N. Prasad, “Manipulating nanoscale interactions in a polymer nanocomposite for chiral control of linear and nonlinear optical functions,” Adv. Mater. 26(10), 1607–1611 (2014).
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H. S. Kang, K. H. Kim, M. S. Kim, K. T. Park, K. M. Kim, T. H. Lee, C. Y. Lee, J. Joo, D. W. Lee, Y. R. Hong, K. Kim, G. J. Lee, and J. I. Jin, “Electrical characteristics of light-emitting diode based on poly(p-phenylenevinylene) derivatives: CzEH-PPV and OxdEH-PPV,” Synth. Met. 130(3), 279–283 (2002).
[Crossref]

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H. S. Kang, K. H. Kim, M. S. Kim, K. T. Park, K. M. Kim, T. H. Lee, C. Y. Lee, J. Joo, D. W. Lee, Y. R. Hong, K. Kim, G. J. Lee, and J. I. Jin, “Electrical characteristics of light-emitting diode based on poly(p-phenylenevinylene) derivatives: CzEH-PPV and OxdEH-PPV,” Synth. Met. 130(3), 279–283 (2002).
[Crossref]

Lee, G. J.

G. J. Lee, J. Park, E. Kim, Y. Lee, K. Kim, H. Cheong, C. Yoon, Y. D. Son, and J. Jang, “Microstructure of femtosecond laser-induced grating in amorphous silicon,” Opt. Express 13(17), 6445–6453 (2005).
[Crossref] [PubMed]

H. S. Kang, K. H. Kim, M. S. Kim, K. T. Park, K. M. Kim, T. H. Lee, C. Y. Lee, J. Joo, D. W. Lee, Y. R. Hong, K. Kim, G. J. Lee, and J. I. Jin, “Electrical characteristics of light-emitting diode based on poly(p-phenylenevinylene) derivatives: CzEH-PPV and OxdEH-PPV,” Synth. Met. 130(3), 279–283 (2002).
[Crossref]

G. J. Lee, K. Kim, and J. I. Jin, “Mechanism of one-and two-photon absorption induced photoluminescence in PPV type, electroluminescent polymer,” Opt. Commun. 203(1-2), 151–157 (2002).
[Crossref]

Lee, T. H.

H. S. Kang, K. H. Kim, M. S. Kim, K. T. Park, K. M. Kim, T. H. Lee, C. Y. Lee, J. Joo, D. W. Lee, Y. R. Hong, K. Kim, G. J. Lee, and J. I. Jin, “Electrical characteristics of light-emitting diode based on poly(p-phenylenevinylene) derivatives: CzEH-PPV and OxdEH-PPV,” Synth. Met. 130(3), 279–283 (2002).
[Crossref]

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M. J. Cho, S. J. Kim, S. H. Yoon, J. Shin, T. R. Hong, H. J. Kim, Y. H. Son, J. S. Kang, H. A. Um, T. W. Lee, J. K. Bin, B. S. Lee, J. H. Yang, G. S. Chae, J. H. Kwon, and D. H. Choi, “New bipolar host materials for realizing blue phosphorescent organic light-emitting diodes with high efficiency at 1000 cd/m2.,” ACS Appl. Mater. Interfaces 6(22), 19808–19815 (2014).
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Lidzey, D. G.

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M. Liu, L. Zhang, and T. Wang, “Supramolecular chirality in self-assembled systems,” Chem. Rev. 115(15), 7304–7397 (2015).
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H. S. Oh, S. Liu, H. Jee, A. Baev, M. T. Swihart, and P. N. Prasad, “Chiral poly(fluorene-alt-benzothiadiazole) (PFBT) and nanocomposites with gold nanoparticles: plasmonically and structurally enhanced chirality,” J. Am. Chem. Soc. 132(49), 17346–17348 (2010).
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H. S. Oh, G. S. He, W. C. Law, A. Baev, H. Jee, X. Liu, A. Urbas, C. W. Lee, B. L. Choi, M. T. Swihart, and P. N. Prasad, “Manipulating nanoscale interactions in a polymer nanocomposite for chiral control of linear and nonlinear optical functions,” Adv. Mater. 26(10), 1607–1611 (2014).
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M. Gross, D. C. Muller, H. G. Nothofer, U. Scherf, D. Neher, C. Brauchle, and K. Meerholz, “Improving the performance of doped π-conjugated polymers for use in organic light-emitting diodes,” Nature 405(6787), 661–665 (2000).
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S. J. George, T. F. A. de Greef, R. Bovee, J. L. J. van Dongen, A. P. H. J. Schenning, and E. W. Meijer, “Photodimerization processes in self-assembled chiral oligo(p-phenylenevinylene) bolaamphiphiles,” Chem. Asian J. 4(6), 910–917 (2009).
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R. Abbel, A. P. H. J. Schenning, and E. W. Meijer, “Molecular weight optimum in the mesoscopic order of chiral fluorene copolymer films,” Macromolecules 41(20), 7497–7504 (2008).
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A. R. A. Palmans and E. W. Meijer, “Amplification of chirality in dynamic supramolecular aggregates,” Angew. Chem. Int. Ed. Engl. 46(47), 8948–8968 (2007).
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T. Miteva, A. Meisel, W. Knoll, H. G. Nothofer, U. Scherf, D. C. Muller, and D. Neher, “Improving the performance of polyfluorene‐based organic light‐emitting diodes via end‐capping,” Adv. Mater. 13(8), 565–570 (2001).
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Meskers, S. C. J.

M. Savoini, P. Biagioni, S. C. J. Meskers, L. Duo, B. Hecht, and M. Finazzi, “Spontaneous formation of left-and right-handed cholesterically ordered domains in an enantiopure chiral polyfluorene film,” J. Phys. Chem. Lett. 2(12), 1359–1362 (2011).
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G. Lakhwani, J. Gielen, M. Kemerink, P. C. M. Christianen, R. A. J. Janssen, and S. C. J. Meskers, “Intensive chiroptical properties of chiral polyfluorenes associated with fibril formation,” J. Phys. Chem. B 113(43), 14047–14051 (2009).
[Crossref] [PubMed]

M. Oda, H. G. Nothofer, U. Scherf, S. C. J. Meskers, and D. Neher, “Circularly polarized electroluminescence from liquid‐crystalline chiral polyfluorenes,” Adv. Mater. 12(5), 362–365 (2000).
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Miteva, T.

T. Miteva, A. Meisel, W. Knoll, H. G. Nothofer, U. Scherf, D. C. Muller, and D. Neher, “Improving the performance of polyfluorene‐based organic light‐emitting diodes via end‐capping,” Adv. Mater. 13(8), 565–570 (2001).
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S. Guha, M. Knaapila, D. Moghe, Z. Konopkova, M. Torkkeli, M. Fritsch, and U. Scherf, “Persistence of nematic liquid crystalline phase in a polyfluorene‐based organic semiconductor: A high pressure study,” J. Polym. Sci., B, Polym. Phys. 52(15), 1014–1023 (2014).
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T. Miteva, A. Meisel, W. Knoll, H. G. Nothofer, U. Scherf, D. C. Muller, and D. Neher, “Improving the performance of polyfluorene‐based organic light‐emitting diodes via end‐capping,” Adv. Mater. 13(8), 565–570 (2001).
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M. Gross, D. C. Muller, H. G. Nothofer, U. Scherf, D. Neher, C. Brauchle, and K. Meerholz, “Improving the performance of doped π-conjugated polymers for use in organic light-emitting diodes,” Nature 405(6787), 661–665 (2000).
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Neher, D.

M. Oda, H. G. Nothofer, U. Scherf, I. V. Sunjic, D. Richter, W. Regenstein, and D. Neher, “Chiroptical properties of chiral substituted polyfluorenes,” Macromolecules 35(18), 6792–6798 (2002).
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T. Miteva, A. Meisel, W. Knoll, H. G. Nothofer, U. Scherf, D. C. Muller, and D. Neher, “Improving the performance of polyfluorene‐based organic light‐emitting diodes via end‐capping,” Adv. Mater. 13(8), 565–570 (2001).
[Crossref]

M. Gross, D. C. Muller, H. G. Nothofer, U. Scherf, D. Neher, C. Brauchle, and K. Meerholz, “Improving the performance of doped π-conjugated polymers for use in organic light-emitting diodes,” Nature 405(6787), 661–665 (2000).
[Crossref] [PubMed]

M. Oda, H. G. Nothofer, U. Scherf, S. C. J. Meskers, and D. Neher, “Circularly polarized electroluminescence from liquid‐crystalline chiral polyfluorenes,” Adv. Mater. 12(5), 362–365 (2000).
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Nothofer, H. G.

M. Oda, H. G. Nothofer, U. Scherf, I. V. Sunjic, D. Richter, W. Regenstein, and D. Neher, “Chiroptical properties of chiral substituted polyfluorenes,” Macromolecules 35(18), 6792–6798 (2002).
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T. Miteva, A. Meisel, W. Knoll, H. G. Nothofer, U. Scherf, D. C. Muller, and D. Neher, “Improving the performance of polyfluorene‐based organic light‐emitting diodes via end‐capping,” Adv. Mater. 13(8), 565–570 (2001).
[Crossref]

M. Gross, D. C. Muller, H. G. Nothofer, U. Scherf, D. Neher, C. Brauchle, and K. Meerholz, “Improving the performance of doped π-conjugated polymers for use in organic light-emitting diodes,” Nature 405(6787), 661–665 (2000).
[Crossref] [PubMed]

M. Oda, H. G. Nothofer, U. Scherf, S. C. J. Meskers, and D. Neher, “Circularly polarized electroluminescence from liquid‐crystalline chiral polyfluorenes,” Adv. Mater. 12(5), 362–365 (2000).
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B. Nowacki, H. Oh, C. Zanlorenzi, H. Jee, A. Baev, P. N. Prasad, and L. Akcelrud, “Design and synthesis of polymers for chiral photonics,” Macromolecules 46(18), 7158–7165 (2013).
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M. Oda, H. G. Nothofer, U. Scherf, I. V. Sunjic, D. Richter, W. Regenstein, and D. Neher, “Chiroptical properties of chiral substituted polyfluorenes,” Macromolecules 35(18), 6792–6798 (2002).
[Crossref]

M. Oda, H. G. Nothofer, U. Scherf, S. C. J. Meskers, and D. Neher, “Circularly polarized electroluminescence from liquid‐crystalline chiral polyfluorenes,” Adv. Mater. 12(5), 362–365 (2000).
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Oh, H.

B. Nowacki, H. Oh, C. Zanlorenzi, H. Jee, A. Baev, P. N. Prasad, and L. Akcelrud, “Design and synthesis of polymers for chiral photonics,” Macromolecules 46(18), 7158–7165 (2013).
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H. S. Oh, G. S. He, W. C. Law, A. Baev, H. Jee, X. Liu, A. Urbas, C. W. Lee, B. L. Choi, M. T. Swihart, and P. N. Prasad, “Manipulating nanoscale interactions in a polymer nanocomposite for chiral control of linear and nonlinear optical functions,” Adv. Mater. 26(10), 1607–1611 (2014).
[Crossref] [PubMed]

H. S. Oh, S. Liu, H. Jee, A. Baev, M. T. Swihart, and P. N. Prasad, “Chiral poly(fluorene-alt-benzothiadiazole) (PFBT) and nanocomposites with gold nanoparticles: plasmonically and structurally enhanced chirality,” J. Am. Chem. Soc. 132(49), 17346–17348 (2010).
[Crossref] [PubMed]

Palmans, A. R. A.

A. R. A. Palmans and E. W. Meijer, “Amplification of chirality in dynamic supramolecular aggregates,” Angew. Chem. Int. Ed. Engl. 46(47), 8948–8968 (2007).
[Crossref] [PubMed]

Park, J.

Park, K. T.

H. S. Kang, K. H. Kim, M. S. Kim, K. T. Park, K. M. Kim, T. H. Lee, C. Y. Lee, J. Joo, D. W. Lee, Y. R. Hong, K. Kim, G. J. Lee, and J. I. Jin, “Electrical characteristics of light-emitting diode based on poly(p-phenylenevinylene) derivatives: CzEH-PPV and OxdEH-PPV,” Synth. Met. 130(3), 279–283 (2002).
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J. C. Yan, X. Cheng, Q. L. Zhou, and J. Pei, “Chiral polyfluorene derivatives: Synthesis, chiroptical properties, and investigation of the structure-property relationships,” Macromolecules 40(4), 832–839 (2007).
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M. Campoy-Quiles, G. Heliotis, R. Xia, M. Ariu, M. Pintani, P. Etchegoin, and D. D. C. Bradley, “Ellipsometric characterization of the optical constants of polyfluorene gain media,” Adv. Funct. Mater. 15(6), 925–933 (2005).
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Prasad, P. N.

H. S. Oh, G. S. He, W. C. Law, A. Baev, H. Jee, X. Liu, A. Urbas, C. W. Lee, B. L. Choi, M. T. Swihart, and P. N. Prasad, “Manipulating nanoscale interactions in a polymer nanocomposite for chiral control of linear and nonlinear optical functions,” Adv. Mater. 26(10), 1607–1611 (2014).
[Crossref] [PubMed]

G. S. He, M. J. Cho, W. J. Kim, A. Baev, A. Urbas, and P. N. Prasad, “Polarimetric z-scan study of nonlinear chiroptic properties of chiral polyfluorene,” Adv. Opt. Mater. 1(10), 763–767 (2013).
[Crossref]

B. Nowacki, H. Oh, C. Zanlorenzi, H. Jee, A. Baev, P. N. Prasad, and L. Akcelrud, “Design and synthesis of polymers for chiral photonics,” Macromolecules 46(18), 7158–7165 (2013).
[Crossref]

H. S. Oh, S. Liu, H. Jee, A. Baev, M. T. Swihart, and P. N. Prasad, “Chiral poly(fluorene-alt-benzothiadiazole) (PFBT) and nanocomposites with gold nanoparticles: plasmonically and structurally enhanced chirality,” J. Am. Chem. Soc. 132(49), 17346–17348 (2010).
[Crossref] [PubMed]

Rampey, M. E.

R. Fiesel, C. E. Halkyard, M. E. Rampey, L. Kloppenburg, S. L. Studer-Martinez, U. Scherf, and U. H. F. Bunz, “Aggregation and chiroptical behavior of a high molecular weight chirally substituted dialkylpoly(p-phenyleneethynylene),” Macromol. Rapid Commun. 20(3), 107–111 (1999).
[Crossref]

Regenstein, W.

M. Oda, H. G. Nothofer, U. Scherf, I. V. Sunjic, D. Richter, W. Regenstein, and D. Neher, “Chiroptical properties of chiral substituted polyfluorenes,” Macromolecules 35(18), 6792–6798 (2002).
[Crossref]

Richter, D.

M. Oda, H. G. Nothofer, U. Scherf, I. V. Sunjic, D. Richter, W. Regenstein, and D. Neher, “Chiroptical properties of chiral substituted polyfluorenes,” Macromolecules 35(18), 6792–6798 (2002).
[Crossref]

Savoini, M.

M. Savoini, P. Biagioni, S. C. J. Meskers, L. Duo, B. Hecht, and M. Finazzi, “Spontaneous formation of left-and right-handed cholesterically ordered domains in an enantiopure chiral polyfluorene film,” J. Phys. Chem. Lett. 2(12), 1359–1362 (2011).
[Crossref]

Schenning, A. P. H. J.

S. J. George, T. F. A. de Greef, R. Bovee, J. L. J. van Dongen, A. P. H. J. Schenning, and E. W. Meijer, “Photodimerization processes in self-assembled chiral oligo(p-phenylenevinylene) bolaamphiphiles,” Chem. Asian J. 4(6), 910–917 (2009).
[Crossref] [PubMed]

R. Abbel, A. P. H. J. Schenning, and E. W. Meijer, “Molecular weight optimum in the mesoscopic order of chiral fluorene copolymer films,” Macromolecules 41(20), 7497–7504 (2008).
[Crossref]

Scherf, U.

S. Guha, M. Knaapila, D. Moghe, Z. Konopkova, M. Torkkeli, M. Fritsch, and U. Scherf, “Persistence of nematic liquid crystalline phase in a polyfluorene‐based organic semiconductor: A high pressure study,” J. Polym. Sci., B, Polym. Phys. 52(15), 1014–1023 (2014).
[Crossref]

U. Scherf and E. J. List, “Semiconducting polyfluorenes–Towards reliable structure–property relationships,” Adv. Mater. 14(7), 477–487 (2002).
[Crossref]

M. Oda, H. G. Nothofer, U. Scherf, I. V. Sunjic, D. Richter, W. Regenstein, and D. Neher, “Chiroptical properties of chiral substituted polyfluorenes,” Macromolecules 35(18), 6792–6798 (2002).
[Crossref]

T. Miteva, A. Meisel, W. Knoll, H. G. Nothofer, U. Scherf, D. C. Muller, and D. Neher, “Improving the performance of polyfluorene‐based organic light‐emitting diodes via end‐capping,” Adv. Mater. 13(8), 565–570 (2001).
[Crossref]

M. Gross, D. C. Muller, H. G. Nothofer, U. Scherf, D. Neher, C. Brauchle, and K. Meerholz, “Improving the performance of doped π-conjugated polymers for use in organic light-emitting diodes,” Nature 405(6787), 661–665 (2000).
[Crossref] [PubMed]

M. Oda, H. G. Nothofer, U. Scherf, S. C. J. Meskers, and D. Neher, “Circularly polarized electroluminescence from liquid‐crystalline chiral polyfluorenes,” Adv. Mater. 12(5), 362–365 (2000).
[Crossref]

R. Fiesel, C. E. Halkyard, M. E. Rampey, L. Kloppenburg, S. L. Studer-Martinez, U. Scherf, and U. H. F. Bunz, “Aggregation and chiroptical behavior of a high molecular weight chirally substituted dialkylpoly(p-phenyleneethynylene),” Macromol. Rapid Commun. 20(3), 107–111 (1999).
[Crossref]

R. Fiesel and U. Scherf, “Aggregation-induced CD effects in chiral poly(2,5-dialkoxy-1,4-phenylene)s,” Acta Polym. 49(8), 445–449 (1998).
[Crossref]

Schuessler, H. A.

Shah, N. C.

P. L. Stiles, J. A. Dieringer, N. C. Shah, and R. P. Van Duyne, “Surface-enhanced Raman spectroscopy,” Annu. Rev. Anal. Chem. (Palo Alto, Calif.) 1(1), 601–626 (2008).
[Crossref] [PubMed]

Shin, J.

M. J. Cho, S. J. Kim, S. H. Yoon, J. Shin, T. R. Hong, H. J. Kim, Y. H. Son, J. S. Kang, H. A. Um, T. W. Lee, J. K. Bin, B. S. Lee, J. H. Yang, G. S. Chae, J. H. Kwon, and D. H. Choi, “New bipolar host materials for realizing blue phosphorescent organic light-emitting diodes with high efficiency at 1000 cd/m2.,” ACS Appl. Mater. Interfaces 6(22), 19808–19815 (2014).
[Crossref] [PubMed]

Smith, D. L.

D. McBranch, I. H. Campbell, D. L. Smith, and J. P. Ferraris, “Optical determination of chain orientation in electroluminescent polymer films,” Appl. Phys. Lett. 66(10), 1175–1177 (1995).
[Crossref]

Son, Y. D.

Son, Y. H.

M. J. Cho, S. J. Kim, S. H. Yoon, J. Shin, T. R. Hong, H. J. Kim, Y. H. Son, J. S. Kang, H. A. Um, T. W. Lee, J. K. Bin, B. S. Lee, J. H. Yang, G. S. Chae, J. H. Kwon, and D. H. Choi, “New bipolar host materials for realizing blue phosphorescent organic light-emitting diodes with high efficiency at 1000 cd/m2.,” ACS Appl. Mater. Interfaces 6(22), 19808–19815 (2014).
[Crossref] [PubMed]

Stiles, P. L.

P. L. Stiles, J. A. Dieringer, N. C. Shah, and R. P. Van Duyne, “Surface-enhanced Raman spectroscopy,” Annu. Rev. Anal. Chem. (Palo Alto, Calif.) 1(1), 601–626 (2008).
[Crossref] [PubMed]

Studer-Martinez, S. L.

R. Fiesel, C. E. Halkyard, M. E. Rampey, L. Kloppenburg, S. L. Studer-Martinez, U. Scherf, and U. H. F. Bunz, “Aggregation and chiroptical behavior of a high molecular weight chirally substituted dialkylpoly(p-phenyleneethynylene),” Macromol. Rapid Commun. 20(3), 107–111 (1999).
[Crossref]

Sunjic, I. V.

M. Oda, H. G. Nothofer, U. Scherf, I. V. Sunjic, D. Richter, W. Regenstein, and D. Neher, “Chiroptical properties of chiral substituted polyfluorenes,” Macromolecules 35(18), 6792–6798 (2002).
[Crossref]

Swihart, M. T.

H. S. Oh, G. S. He, W. C. Law, A. Baev, H. Jee, X. Liu, A. Urbas, C. W. Lee, B. L. Choi, M. T. Swihart, and P. N. Prasad, “Manipulating nanoscale interactions in a polymer nanocomposite for chiral control of linear and nonlinear optical functions,” Adv. Mater. 26(10), 1607–1611 (2014).
[Crossref] [PubMed]

H. S. Oh, S. Liu, H. Jee, A. Baev, M. T. Swihart, and P. N. Prasad, “Chiral poly(fluorene-alt-benzothiadiazole) (PFBT) and nanocomposites with gold nanoparticles: plasmonically and structurally enhanced chirality,” J. Am. Chem. Soc. 132(49), 17346–17348 (2010).
[Crossref] [PubMed]

Tanto, B.

W. Chunwaschirasiri, B. Tanto, D. L. Huber, and M. J. Winokur, “Chain conformations and photoluminescence of poly(di-n-octylfluorene),” Phys. Rev. Lett. 94(10), 107402 (2005).
[Crossref] [PubMed]

Torkkeli, M.

S. Guha, M. Knaapila, D. Moghe, Z. Konopkova, M. Torkkeli, M. Fritsch, and U. Scherf, “Persistence of nematic liquid crystalline phase in a polyfluorene‐based organic semiconductor: A high pressure study,” J. Polym. Sci., B, Polym. Phys. 52(15), 1014–1023 (2014).
[Crossref]

Tsoi, W. C.

W. C. Tsoi and D. G. Lidzey, “Raman spectroscopy of fluorene oligomers in the α-, β-and γ-phases,” J. Phys. Condens. Matter 20(12), 125213 (2008).
[Crossref]

Um, H. A.

M. J. Cho, S. J. Kim, S. H. Yoon, J. Shin, T. R. Hong, H. J. Kim, Y. H. Son, J. S. Kang, H. A. Um, T. W. Lee, J. K. Bin, B. S. Lee, J. H. Yang, G. S. Chae, J. H. Kwon, and D. H. Choi, “New bipolar host materials for realizing blue phosphorescent organic light-emitting diodes with high efficiency at 1000 cd/m2.,” ACS Appl. Mater. Interfaces 6(22), 19808–19815 (2014).
[Crossref] [PubMed]

Ungar, G.

M. Grell, D. D. C. Bradley, G. Ungar, J. Hill, and K. S. Whitehead, “Interplay of physical structure and photophysics for a liquid crystalline polyfluorene,” Macromolecules 32(18), 5810–5817 (1999).
[Crossref]

Urbas, A.

H. S. Oh, G. S. He, W. C. Law, A. Baev, H. Jee, X. Liu, A. Urbas, C. W. Lee, B. L. Choi, M. T. Swihart, and P. N. Prasad, “Manipulating nanoscale interactions in a polymer nanocomposite for chiral control of linear and nonlinear optical functions,” Adv. Mater. 26(10), 1607–1611 (2014).
[Crossref] [PubMed]

G. S. He, M. J. Cho, W. J. Kim, A. Baev, A. Urbas, and P. N. Prasad, “Polarimetric z-scan study of nonlinear chiroptic properties of chiral polyfluorene,” Adv. Opt. Mater. 1(10), 763–767 (2013).
[Crossref]

van Dongen, J. L. J.

S. J. George, T. F. A. de Greef, R. Bovee, J. L. J. van Dongen, A. P. H. J. Schenning, and E. W. Meijer, “Photodimerization processes in self-assembled chiral oligo(p-phenylenevinylene) bolaamphiphiles,” Chem. Asian J. 4(6), 910–917 (2009).
[Crossref] [PubMed]

Van Duyne, R. P.

P. L. Stiles, J. A. Dieringer, N. C. Shah, and R. P. Van Duyne, “Surface-enhanced Raman spectroscopy,” Annu. Rev. Anal. Chem. (Palo Alto, Calif.) 1(1), 601–626 (2008).
[Crossref] [PubMed]

Volz, C.

C. Volz, M. Arif, and S. Guha, “Conformations in dioctyl substituted polyfluorene: A combined theoretical and experimental Raman scattering study,” J. Chem. Phys. 126(6), 064905 (2007).
[Crossref] [PubMed]

M. Arif, C. Volz, and S. Guha, “Chain morphologies in semicrystalline polyfluorene: Evidence from Raman scattering,” Phys. Rev. Lett. 96(2), 025503 (2006).
[Crossref] [PubMed]

Wang, T.

M. Liu, L. Zhang, and T. Wang, “Supramolecular chirality in self-assembled systems,” Chem. Rev. 115(15), 7304–7397 (2015).
[Crossref] [PubMed]

Whitehead, K. S.

M. Grell, D. D. C. Bradley, G. Ungar, J. Hill, and K. S. Whitehead, “Interplay of physical structure and photophysics for a liquid crystalline polyfluorene,” Macromolecules 32(18), 5810–5817 (1999).
[Crossref]

Winokur, M. J.

W. Chunwaschirasiri, B. Tanto, D. L. Huber, and M. J. Winokur, “Chain conformations and photoluminescence of poly(di-n-octylfluorene),” Phys. Rev. Lett. 94(10), 107402 (2005).
[Crossref] [PubMed]

Wu, W.

M. T. Bernius, M. Inbasekaran, J. O’Brien, and W. Wu, “Progress with light-emitting polymers,” Adv. Mater. 12(23), 1737–1750 (2000).
[Crossref]

Xia, R.

M. Campoy-Quiles, G. Heliotis, R. Xia, M. Ariu, M. Pintani, P. Etchegoin, and D. D. C. Bradley, “Ellipsometric characterization of the optical constants of polyfluorene gain media,” Adv. Funct. Mater. 15(6), 925–933 (2005).
[Crossref]

Yan, J. C.

J. C. Yan, X. Cheng, Q. L. Zhou, and J. Pei, “Chiral polyfluorene derivatives: Synthesis, chiroptical properties, and investigation of the structure-property relationships,” Macromolecules 40(4), 832–839 (2007).
[Crossref]

Yang, J. H.

M. J. Cho, S. J. Kim, S. H. Yoon, J. Shin, T. R. Hong, H. J. Kim, Y. H. Son, J. S. Kang, H. A. Um, T. W. Lee, J. K. Bin, B. S. Lee, J. H. Yang, G. S. Chae, J. H. Kwon, and D. H. Choi, “New bipolar host materials for realizing blue phosphorescent organic light-emitting diodes with high efficiency at 1000 cd/m2.,” ACS Appl. Mater. Interfaces 6(22), 19808–19815 (2014).
[Crossref] [PubMed]

Yeatman, E. M.

Yoon, C.

Yoon, S. H.

M. J. Cho, S. J. Kim, S. H. Yoon, J. Shin, T. R. Hong, H. J. Kim, Y. H. Son, J. S. Kang, H. A. Um, T. W. Lee, J. K. Bin, B. S. Lee, J. H. Yang, G. S. Chae, J. H. Kwon, and D. H. Choi, “New bipolar host materials for realizing blue phosphorescent organic light-emitting diodes with high efficiency at 1000 cd/m2.,” ACS Appl. Mater. Interfaces 6(22), 19808–19815 (2014).
[Crossref] [PubMed]

Zanlorenzi, C.

B. Nowacki, H. Oh, C. Zanlorenzi, H. Jee, A. Baev, P. N. Prasad, and L. Akcelrud, “Design and synthesis of polymers for chiral photonics,” Macromolecules 46(18), 7158–7165 (2013).
[Crossref]

Zhang, L.

M. Liu, L. Zhang, and T. Wang, “Supramolecular chirality in self-assembled systems,” Chem. Rev. 115(15), 7304–7397 (2015).
[Crossref] [PubMed]

Zhou, Q. L.

J. C. Yan, X. Cheng, Q. L. Zhou, and J. Pei, “Chiral polyfluorene derivatives: Synthesis, chiroptical properties, and investigation of the structure-property relationships,” Macromolecules 40(4), 832–839 (2007).
[Crossref]

ACS Appl. Mater. Interfaces (1)

M. J. Cho, S. J. Kim, S. H. Yoon, J. Shin, T. R. Hong, H. J. Kim, Y. H. Son, J. S. Kang, H. A. Um, T. W. Lee, J. K. Bin, B. S. Lee, J. H. Yang, G. S. Chae, J. H. Kwon, and D. H. Choi, “New bipolar host materials for realizing blue phosphorescent organic light-emitting diodes with high efficiency at 1000 cd/m2.,” ACS Appl. Mater. Interfaces 6(22), 19808–19815 (2014).
[Crossref] [PubMed]

Acta Polym. (1)

R. Fiesel and U. Scherf, “Aggregation-induced CD effects in chiral poly(2,5-dialkoxy-1,4-phenylene)s,” Acta Polym. 49(8), 445–449 (1998).
[Crossref]

Adv. Funct. Mater. (1)

M. Campoy-Quiles, G. Heliotis, R. Xia, M. Ariu, M. Pintani, P. Etchegoin, and D. D. C. Bradley, “Ellipsometric characterization of the optical constants of polyfluorene gain media,” Adv. Funct. Mater. 15(6), 925–933 (2005).
[Crossref]

Adv. Mater. (7)

U. Scherf and E. J. List, “Semiconducting polyfluorenes–Towards reliable structure–property relationships,” Adv. Mater. 14(7), 477–487 (2002).
[Crossref]

M. M. Bournan and E. W. Meijer, “Stereomutation in optically active regioregular polythiophenes,” Adv. Mater. 7(4), 385–387 (1995).
[Crossref]

M. Oda, H. G. Nothofer, U. Scherf, S. C. J. Meskers, and D. Neher, “Circularly polarized electroluminescence from liquid‐crystalline chiral polyfluorenes,” Adv. Mater. 12(5), 362–365 (2000).
[Crossref]

T. Miteva, A. Meisel, W. Knoll, H. G. Nothofer, U. Scherf, D. C. Muller, and D. Neher, “Improving the performance of polyfluorene‐based organic light‐emitting diodes via end‐capping,” Adv. Mater. 13(8), 565–570 (2001).
[Crossref]

H. S. Oh, G. S. He, W. C. Law, A. Baev, H. Jee, X. Liu, A. Urbas, C. W. Lee, B. L. Choi, M. T. Swihart, and P. N. Prasad, “Manipulating nanoscale interactions in a polymer nanocomposite for chiral control of linear and nonlinear optical functions,” Adv. Mater. 26(10), 1607–1611 (2014).
[Crossref] [PubMed]

M. T. Bernius, M. Inbasekaran, J. O’Brien, and W. Wu, “Progress with light-emitting polymers,” Adv. Mater. 12(23), 1737–1750 (2000).
[Crossref]

M. Grell and D. D. C. Bradley, “Polarized luminescence from oriented molecular materials,” Adv. Mater. 11(11), 895–905 (1999).
[Crossref]

Adv. Opt. Mater. (1)

G. S. He, M. J. Cho, W. J. Kim, A. Baev, A. Urbas, and P. N. Prasad, “Polarimetric z-scan study of nonlinear chiroptic properties of chiral polyfluorene,” Adv. Opt. Mater. 1(10), 763–767 (2013).
[Crossref]

Angew. Chem. Int. Ed. Engl. (1)

A. R. A. Palmans and E. W. Meijer, “Amplification of chirality in dynamic supramolecular aggregates,” Angew. Chem. Int. Ed. Engl. 46(47), 8948–8968 (2007).
[Crossref] [PubMed]

Annu. Rev. Anal. Chem. (Palo Alto, Calif.) (1)

P. L. Stiles, J. A. Dieringer, N. C. Shah, and R. P. Van Duyne, “Surface-enhanced Raman spectroscopy,” Annu. Rev. Anal. Chem. (Palo Alto, Calif.) 1(1), 601–626 (2008).
[Crossref] [PubMed]

Appl. Opt. (2)

Appl. Phys. Lett. (1)

D. McBranch, I. H. Campbell, D. L. Smith, and J. P. Ferraris, “Optical determination of chain orientation in electroluminescent polymer films,” Appl. Phys. Lett. 66(10), 1175–1177 (1995).
[Crossref]

Chem. Asian J. (1)

S. J. George, T. F. A. de Greef, R. Bovee, J. L. J. van Dongen, A. P. H. J. Schenning, and E. W. Meijer, “Photodimerization processes in self-assembled chiral oligo(p-phenylenevinylene) bolaamphiphiles,” Chem. Asian J. 4(6), 910–917 (2009).
[Crossref] [PubMed]

Chem. Rev. (1)

M. Liu, L. Zhang, and T. Wang, “Supramolecular chirality in self-assembled systems,” Chem. Rev. 115(15), 7304–7397 (2015).
[Crossref] [PubMed]

J. Am. Chem. Soc. (1)

H. S. Oh, S. Liu, H. Jee, A. Baev, M. T. Swihart, and P. N. Prasad, “Chiral poly(fluorene-alt-benzothiadiazole) (PFBT) and nanocomposites with gold nanoparticles: plasmonically and structurally enhanced chirality,” J. Am. Chem. Soc. 132(49), 17346–17348 (2010).
[Crossref] [PubMed]

J. Chem. Phys. (1)

C. Volz, M. Arif, and S. Guha, “Conformations in dioctyl substituted polyfluorene: A combined theoretical and experimental Raman scattering study,” J. Chem. Phys. 126(6), 064905 (2007).
[Crossref] [PubMed]

J. Opt. A, Pure Appl. Opt. (1)

I. Abdulhalim, “Surface plasmon TE and TM waves at the anisotropic film–metal interface,” J. Opt. A, Pure Appl. Opt. 11(1), 015002 (2009).
[Crossref]

J. Opt. Soc. Am. (1)

J. Phys. Chem. B (1)

G. Lakhwani, J. Gielen, M. Kemerink, P. C. M. Christianen, R. A. J. Janssen, and S. C. J. Meskers, “Intensive chiroptical properties of chiral polyfluorenes associated with fibril formation,” J. Phys. Chem. B 113(43), 14047–14051 (2009).
[Crossref] [PubMed]

J. Phys. Chem. Lett. (1)

M. Savoini, P. Biagioni, S. C. J. Meskers, L. Duo, B. Hecht, and M. Finazzi, “Spontaneous formation of left-and right-handed cholesterically ordered domains in an enantiopure chiral polyfluorene film,” J. Phys. Chem. Lett. 2(12), 1359–1362 (2011).
[Crossref]

J. Phys. Condens. Matter (1)

W. C. Tsoi and D. G. Lidzey, “Raman spectroscopy of fluorene oligomers in the α-, β-and γ-phases,” J. Phys. Condens. Matter 20(12), 125213 (2008).
[Crossref]

J. Polym. Sci., B, Polym. Phys. (1)

S. Guha, M. Knaapila, D. Moghe, Z. Konopkova, M. Torkkeli, M. Fritsch, and U. Scherf, “Persistence of nematic liquid crystalline phase in a polyfluorene‐based organic semiconductor: A high pressure study,” J. Polym. Sci., B, Polym. Phys. 52(15), 1014–1023 (2014).
[Crossref]

Macromol. Rapid Commun. (1)

R. Fiesel, C. E. Halkyard, M. E. Rampey, L. Kloppenburg, S. L. Studer-Martinez, U. Scherf, and U. H. F. Bunz, “Aggregation and chiroptical behavior of a high molecular weight chirally substituted dialkylpoly(p-phenyleneethynylene),” Macromol. Rapid Commun. 20(3), 107–111 (1999).
[Crossref]

Macromolecules (6)

M. Oda, H. G. Nothofer, U. Scherf, I. V. Sunjic, D. Richter, W. Regenstein, and D. Neher, “Chiroptical properties of chiral substituted polyfluorenes,” Macromolecules 35(18), 6792–6798 (2002).
[Crossref]

R. Abbel, A. P. H. J. Schenning, and E. W. Meijer, “Molecular weight optimum in the mesoscopic order of chiral fluorene copolymer films,” Macromolecules 41(20), 7497–7504 (2008).
[Crossref]

J. S. Kim, P. K. H. Ho, C. E. Murphy, and R. H. Friend, “Phase separation in polyfluorene-based conjugated polymer blends: Lateral and vertical analysis of blend spin-cast thin films,” Macromolecules 37(8), 2861–2871 (2004).
[Crossref]

M. Grell, D. D. C. Bradley, G. Ungar, J. Hill, and K. S. Whitehead, “Interplay of physical structure and photophysics for a liquid crystalline polyfluorene,” Macromolecules 32(18), 5810–5817 (1999).
[Crossref]

J. C. Yan, X. Cheng, Q. L. Zhou, and J. Pei, “Chiral polyfluorene derivatives: Synthesis, chiroptical properties, and investigation of the structure-property relationships,” Macromolecules 40(4), 832–839 (2007).
[Crossref]

B. Nowacki, H. Oh, C. Zanlorenzi, H. Jee, A. Baev, P. N. Prasad, and L. Akcelrud, “Design and synthesis of polymers for chiral photonics,” Macromolecules 46(18), 7158–7165 (2013).
[Crossref]

Nature (1)

M. Gross, D. C. Muller, H. G. Nothofer, U. Scherf, D. Neher, C. Brauchle, and K. Meerholz, “Improving the performance of doped π-conjugated polymers for use in organic light-emitting diodes,” Nature 405(6787), 661–665 (2000).
[Crossref] [PubMed]

Opt. Commun. (1)

G. J. Lee, K. Kim, and J. I. Jin, “Mechanism of one-and two-photon absorption induced photoluminescence in PPV type, electroluminescent polymer,” Opt. Commun. 203(1-2), 151–157 (2002).
[Crossref]

Opt. Express (1)

Phys. Rev. Lett. (2)

W. Chunwaschirasiri, B. Tanto, D. L. Huber, and M. J. Winokur, “Chain conformations and photoluminescence of poly(di-n-octylfluorene),” Phys. Rev. Lett. 94(10), 107402 (2005).
[Crossref] [PubMed]

M. Arif, C. Volz, and S. Guha, “Chain morphologies in semicrystalline polyfluorene: Evidence from Raman scattering,” Phys. Rev. Lett. 96(2), 025503 (2006).
[Crossref] [PubMed]

Synth. Met. (1)

H. S. Kang, K. H. Kim, M. S. Kim, K. T. Park, K. M. Kim, T. H. Lee, C. Y. Lee, J. Joo, D. W. Lee, Y. R. Hong, K. Kim, G. J. Lee, and J. I. Jin, “Electrical characteristics of light-emitting diode based on poly(p-phenylenevinylene) derivatives: CzEH-PPV and OxdEH-PPV,” Synth. Met. 130(3), 279–283 (2002).
[Crossref]

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Figures (8)

Fig. 1
Fig. 1 (a) Synthetic procedure for and molecular structure of the PFP polymer with pendant alkyl groups. (b) Differential scanning calorimetry scan of the PFP polymer.
Fig. 2
Fig. 2 Circular dichroism spectra of the (a) pristine (PFP1, PFP2, PFP3) and (b) annealed (PFP2A, PFP3A) films. Dissymmetry factor (g–value) spectra of the (c) pristine and (d) annealed films.
Fig. 3
Fig. 3 (a) Absorption spectra of the pristine (PFP1, PFP2, PFP3) and annealed (PFP3A) films. (b) Normalized absorption spectra of the PFP films (PFP1, PFP3, PFP3A) and the PFP solution. In (b), the absorption spectra are expanded to show the blue shift of the absorption peak.
Fig. 4
Fig. 4 (a) Fit of the experimental Raman spectrum of the annealed PFP3A film to eight Lorentzian multipeaks. (b) SERS spectra of the pristine (PFP1, PFP2, PFP3) and annealed (PFP3A) films.
Fig. 5
Fig. 5 Refractive index and extinction coefficient spectra of the (a) pristine (PFP3) and (b) annealed (PFP3A) films.
Fig. 6
Fig. 6 (a) Extinction spectrum of the PFP film on gold by Mie theory. (b) ATR spectra of p-polarized light for the pristine (PFP1, PFP3) and annealed (PFP3A) films under the Kretschmann configuration. The ATR spectra of the PFP films are compared with that of the bare gold layer. In the ATR spectra, reflection losses of at the entrance and exit facets of the prism are corrected using Fresnel formulas.
Fig. 7
Fig. 7 (a) Optical absorption and (b) CD spectra of the pristine (PF) and annealed (PF-A) films. (c) Fit of the experimental Raman spectrum of the annealed PF-A film to eight Lorentzian multipeaks. (d) SERS spectra of the pristine and annealed films. In (a), the inset figure shows the molecular structure of the PF polymer with pendant alkyl groups.
Fig. 8
Fig. 8 Optimized geometries of (a) PF and (b) PFP polymers with pendant alkyl groups. In figure, (F), fluorene; (P), phenylene; (A), alkyl side chains.

Equations (8)

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

θ ( λ ) = tan 1 ( E R E L E R + E L ) = tan 1 ( 1 I L / I R 1 + I L / I R ) = tan 1 ( 1 ρ ( λ ) 1 + ρ ( λ ) )   ,   
I L ( R ) ( λ ) = I L ( R ) 0 exp ( 4 π λ k L ( R ) ) ,
ρ ( λ ) = I L ( λ ) / I R ( λ ) = exp ( 4 π λ Δ k ( λ ) ) = exp ( Δ A ( λ ) ) ,
Δ A ( λ ) = A L ( λ ) A R ( λ ) = 4 π λ Δ k ( λ ) = 4 π λ [ k L ( λ ) k R ( λ ) ] .
θ ( λ ) Δ A ( λ ) 4 = π λ Δ k ( λ ) (radians)
g ( λ ) = Δ A A a v g = A L ( λ ) A R ( λ ) ( A L ( λ ) + A R ( λ ) 2 )
d π 2 sin 2 θ d π 2 = 1 1 + k π z 2 k π x
σ e x t ( λ ) = 18 π N V λ ln ( 10 ) ε d 3 / 2 ε m I ( λ ) [ ( ε m R ( λ ) + χ ε d ( λ ) ) 2 + ( ε m I ( λ ) ) 2 ]

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