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Abstract
Inorganic perovskite has attracted great interest due to its excellent optoelectronic properties. There are much less low band gap halide perovskite semiconductors, and CsPbCl3 is one of a wide band gap semiconductor in the perovskite family. In this study, a 0.5-mm CsPbCl3 perovskite single crystal with tetragonal structure and a direct band gap of 2.86 ± 0.3 eV is synthesized by flash evaporation of CsCl-PbCl2 solution. An ultraviolet photodetector based on a CsPbCl3 single crystal is fabricated, showing a photoresponse in a wide wavelength range of 280–435 nm, with a maximum responsivity of 0.272 A/W at 410 nm. Rise and decay response times of the device are less than 28.4 and 2.7 ms, respectively. The good performance of this CsPbCl3 photodetector indicates promising applications in the field of UV optoelectronic devices.
© 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
1. Introduction
Harvesting solar energy is widely investigated using a range of innovative technologies, including photovoltaic devices, [1,2] photocatalysis, [3–10] water splitting, [11–14] etc [15–17]. As important solar conversion materials, [1,18,19] perovskite semiconductors have attracted enormous attention for prospective applications in photodetectors, [20,21] X-ray imaging, [22,23] lasers, [24,25] light emitting diodes, [26] etc [15,27]. The family of perovskite semiconductors has the general structural formula of ABX3, where cation A is CH3NH3+(MA), NH2CHNH2+(FA), or Cs+, cation B can be Pb2+ or Sn2+, and X is one or two of the halide anions Cl−, Br−, or I− [27–30]. Perovskite semiconductors have unique electronic and optical properties, including high mobility, long carrier diffusion length, high optical absorption, tunable band gap, and a “home lab"-grade low-cost fabrication process [26,29,31].
In contrast to other members of the inorganic halide perovskite family with the general structure CsPbX3 (X = Cl, Br, I), CsPbCl3 is a wide-band gap semiconductor. Due to the wide band gap of 2.85 eV [32] and the high exciton binding energy of 75 meV [33], inorganic CsPbCl3 is a promising semiconductor for constructing perovskite-based ultraviolet (UV) optoelectronic devices, such as UV photodetectors [34] as well as laser and near-UV LEDs for white light illumination [35–39]. Currently, in most studies on CsPbCl3, forms of polycrystalline thin films, nanocrystals, and nanowires are used [34,40–42]. To thoroughly understand the essential optoelectronic properties and bridge the diversity between polycrystalline and single crystal counterparts, large monocrystals are in high demand. However, to the best of our knowledge, only few studies have been reported on the optoelectronic properties of CsPbCl3 single crystals. Furthermore, CsPbCl3 has a cubic perovskite structure at temperatures above 320 K and a tetragonal structure below that temperature. Most reported CsPbCl3 perovskite nanocrystals are in cubic structure, while only few studies have paid attention to the optoelectronic properties of CsPbCl3 perovskite nanocrystals with tetragonal structure.
In this study, a single crystal of tetragonal CsPbCl3 was synthesized and grown by solvent flash vaporization. A photodetector was fabricated from this individual CsPbCl3 single crystal, which exhibited high responsivity (0.272 A/W) and rapid response (28.4 ms rise, 2.7 ms decay).
2. Experimental details
CsCl (99.9%, Aladdin), PbCl2 (99.9%, Aladdin), dimethyl sulfoxide (DMSO, Aladdin) were used as received from the manufacturer. The CsPbCl3 crystal was seeded by dissolving CsCl with PbCl2 in DMSO [34]. In order to obtain large CsPbCl3 single crystals, the CsPbCl3 seeds were soaked in saturated DMSO solution containing CsCl and PbCl2, following rapid evaporation within ∼20 s at 150–200 °C.
CsPbCl3 crystals were characterized by X-ray diffraction (XRD, Cu Kα, θ–2θ, Philips X’Pert Pro MPD), absorption spectroscopy applying Kubelka–Munk diffused reflection (UV–3600, Shimadzu Ltd.), and X-ray photoelectron spectroscopy (XPS, ESCALAB 250Xi, Thermo-VG Scientific) with calibration based on the C 1s peak at 284.81 eV. As electrodes, 200-nm Au films were evaporated onto the CsPbCl3 single crystal. A 500-W Xe lamp was employed as light source. The electric properties of the CsPbCl3 photodetector were measured using a Keysight B2902A Source Meter.
Structural and electronic property calculations were performed within the spin-polarized density-functional theory framework using the VASP code [43,44]. Ion–electron interactions and exchange–correlation functional are treated by projected augmented wave (PAW) approximation [45] and PBE-generalized gradient approximation (GGA), [46] respectively. All atoms were fully relaxed until the force on each atom was less than 0.01 eV/ Å. Monkhorst–Pack k-grids [47] of 5 × 5 × 5 (20 × 20 × 20) were used in structural relaxation (static calculations). A Gaussian smearing of 0.14 eV was used.
3. Results and discussion
A CsPbCl3 single crystal with exposed (100) crystallographic plane was successfully fabricated by solvent flash vaporization. Figure 1(a) presents the powder X-ray diffraction (PXRD) pattern of an individual ∼500-µm CsPbCl3 single crystal. The strong diffraction peaks are narrow and sharp, which indicates that CsPbCl3 was well crystallized. The XRD pattern of the sample matches well with the tetragonal perovskite structure (JCPDS: 18–0366), and the space group is assigned to P4 mm with the unit-cell parameters a = b = 5.584 Å and c = 5.623 Å. The XRD pattern of the exposed facet of the individual CsPbCl3 single crystal revealed diffraction peaks of both (002) and (200) planes. This co-occurrence of (002) and (200) peaks can be attributed to their close d values, i.e., 2.8115 Å for the (002) plane and 2.792 Å for the (200) plane. The single crystal facet was assigned to the (200) facet after detailed analysis [48]. The stoichiometric ratio of the elements was characterized by energy-dispersive X-ray spectroscopy (EDS), and the calculated Cs:Pb:Cl atomic ratio was 1:1:2.98.
Fig. 1. (a) XRD pattern of an individual CsPbCl3 single crystal. Left inset: optical microscopy of the CsPbCl3 single crystal with enlargement of (002) and (200) peaks; right inset: photograph of the CsPbCl3 single crystal. (b) Optical absorption of CsPbCl3 with tetragonal perovskite structure. Inset: (αhν)2∼hν Tauc plot.
Figure 1(b) presents the optical absorption spectrum of the CsPbCl3 single crystal. The absorption edge is located at 430 nm, and the direct optical band gap was calculated to be 2.86 ± 0.3 eV by linear fitting of the (αhν)2∼hν Tauc plot. The band gap of CsPbCl3 agrees well with the reported value of 2.86 eV determined by density functional theory and UV-Vis-IR absorption spectroscopy [33]. The band gap of tetragonal CsPbCl3 is lower than that of the reported counterpart of cubic CsPbCl3, which has been reported to be 2.92 eV for polycrystals and ∼2.98 eV for microwire networks [48].
Figure 2(a) presents the XPS valence band spectrum (VBS) of the CsPbCl3 crystal. The valence band maximum (VBM) was estimated by linear extrapolation of the peak to the baseline, and the CsPbCl3 crystal exhibited a band edge position of 0.866 eV below the Fermi energy, which is characteristic for p-type conductors [49]. The core-level XPS spectra of Cs, Pb, and Cl are presented in Figs. 2(b)–2(d). The two peaks of Cs 3d5/2 and Cs 3d3/2 are located at 723.9 and 737.8 eV, respectively, with spin-orbit splitting of 13.9 eV. The two peaks centered at 143 and 138.1 eV originate from Pb 4f5/2 and Pb 4f7/2, respectively. The high-resolution XPS spectrum of Cl 2p shows two representative peaks located at 197.6 and 199.2 eV, resulting from 2p1/2 and 2p3/2, respectively [16]. The energy deviation values of spin-orbit splitting in Cs 3d, Pb 4f, and Cl 2p are 13.9, 4.9, and 1.6 eV, respectively, which is consistent with reported values [50].
Fig. 2. High-resolution XPS analysis of a CsPbCl3 single crystal. (a) XPS valence band spectrum (VBS). Inset: enlargement of VBS around the Fermi level. (b–d) XPS spectra of Cs 3d (b), Pb 4f (c), and Cl 2p (d).
Band structure, DOS, and PDOS of tetragonal CsPbCl3 were obtained by DFT calculations, as shown in Fig. 3. According to the energy band structure, the narrowest separation between the top of the valence band and the bottom of the conduction band occurs at point A, resulting in a direct band gap for CsPbCl3. Based on DOS and PDOS (Fig. 3), a peak at approximately –9.5 eV is mainly attributed to the Cs-p orbital, which is in agreement with the literature [51]. This study also indicated that the peak at 9.6 eV in the XPS VB spectrum is attributed to Cs p. In addition, according to the NIST X-ray Photoelectron Spectroscopy Database, the energy of Cs 5p is approximately 9.6 eV, which is basically consistent with our experimental and numerical results. Theoretical calculations using different functions are summarized in Table 1. The direct band gap calculated for the tetragonal phase of CsPbCl3 is 1.975 eV, which is in good agreement with a reported value obtained using the PBE exchange-correlation functional [51].
Fig. 3. Electronic properties of tetragonal CsPbCl3. (a) Band structure. (b) Total density of states (DOS). (c) Partial density of states (PDOS) for atoms in the unit cell. (d) PDOS for atomic orbitals of atoms in the unit cell.
Table 1. Comparison of experimental and theoretical values (obtained by PBE and HSE06) of the band gap of tetragonal CsPbCl3.
Current-voltage (I-V) curves of the CsPbCl3 single crystal in the dark and under 320-nm UV light illumination are plotted in Fig. 4(a). Au film electrodes with a distance of 100 µm and an effective active area of 1.47 × 10–4 cm2 were deposited onto the CsPbCl3 single crystal using a mask. Smooth linear I-V characteristic indicates a good ohmic contact between Au electrodes and CsPbCl3 single crystal. The current in the dark is about 0.13 µA under a bias voltage of 1 V, and illumination with UV light resulted in a considerable current increase.
Fig. 4. (a) I−V characteristics of the CsPbCl3 single crystal photodetector measured in the dark and under 320-nm light illumination. (b) Spectral response of the CsPbCl3 single crystal photodetector. (c) Photocurrent and responsivity for different light illumination powers. (d) Detectivity of the photodetector.
The spectral responsivity of the CsPbCl3 single crystal photodetector between 280 and 435 nm for an applied bias voltage of 1 V is presented in Fig. 4(b). The responsivity exhibits a sharp cutoff wavelength at around 435 nm, which corresponds to the photodetector’s band gap of 433 nm (2.86 eV). The responsivity of the photodetector decreased to nearly zero for wavelengths longer than 435 nm.
The responsivity R of the photodetector can be calculated as R = (Ip – Id)/PiS, where Ip is the photocurrent under light illumination, Id the dark current, Pi the incident light power density, and S the effective active area of the photodetector [53]. The responsivity of the CsPbCl3 single crystal photodetector is larger than 0.16 A/W in the UV-light range of 280–400 nm, with maximum responsivity of 0.272 A/W around 380–400 nm.
The variation of responsivity and photocurrent as a function of the incident light power is depicted in Fig. 4(c), showing that the responsivity of the photodetector decreases with increasing incident light power with a maximum R value of 0.37 A/W. The responsivity of our prototypical photodetector below 1 V bias is almost seven times higher than that of the reported MAPbCl3 single crystal UV photodetector, which exhibits a responsivity of 0.0469 A/W [54]. The photocurrent increases with increasing illumination intensity. This is attributed to the number of photogenerated carriers, which is proportional to the absorbed photon flux. The fit line reveals that the photocurrent is proportional to the light intensity. Figure 4(d) presents the detectivity for different wavelengths. The detectivity of the photodetector was calculated by $\textrm{D}^{\ast} = \textrm{R}\sqrt {\textrm{S}} / \sqrt {\textrm{2e}{\textrm{I}_\textrm{d}}}$, where R is the responsivity, S the effective active area, e the electron charge, and Id the dark current [53]. The detectivity is higher than 1010 Jones in the wavelength range of 280–435 nm, i.e., in the UV-violet light spectral range.
Figure 5(a) shows the time-dependent photocurrent curves (I−t) at a bias of 1 V under 360-nm light illumination at successive on/off cycles switched by a mechanical chopper. The photodetector responds quickly and accurately to the changing light signal. The photocurrent is quite uniform during the measurement cycles, which is beneficial for practical applications. Rise and decay time are defined as photocurrent increase from 10% to 90% of the maximum value and vice versa, respectively. The calculated rise and decay times are 28.4 and 2.7 ms, respectively, which are faster than those of cubic CsPbCl3 nanocrystals [55]. This remarkable photoresponse performance of the tetragonal CsPbCl3 photodetector is attributed to its high-quality single crystal and large crystal size, as presented in Table 2.
Fig. 5. (a) On–off switching properties of the CsPbCl3 single crystal photodetector, (b) A single normalized period of the photoresponse for calculating the response times of the devices.
Table 2. Comparison of a solution-processed CsPbCl3 single crystal photodetector and other UV photodetectors.
5. Conclusion
In this study, a single crystal of tetragonal CsPbCl3 has been synthesized by flash evaporation of a mixed solution of CsCl/PbCl2. A photodetector has been fabricated based on this individual CsPbCl3 single crystal, which uses In/Au as the electrode. The spectral response of this photodetector ranges between 280 and 435 nm, with maximum responsivity of 0.268 A/W at 360 nm, and its rise and decay times are 28.4 and 2.7 ms, respectively. Our primary results indicate that the single crystal of tetragonal CsPbCl3 can serve as a promising high-performance ultraviolet-violet photodetector.
Funding
National Natural Science Foundation of China (51872054, 61604045); Department of Education of Guangdong Province (2018KZDXM052, 2017KQNCX152); Natural Science Foundation of Guangdong Province (2018A030313041); Start-up Funds of Hundred Talent Program of Guangzhou University (RD2020069); Innovation Research for the Postgraduates of Guangzhou University (2019GDJC-M45); National College Students Innovation and Entrepreneurship Training Program (201911078021).
Disclosures
The authors declare no conflict of interest.
References
1. Z. Liu, K. Deng, J. Hu, and L. Li, “Coagulated SnO2 Colloids for High-Performance Planar Perovskite Solar Cells with Negligible Hysteresis and Improved Stability,” Angew. Chem., Int. Ed. 58(33), 11497–11504 (2019). [CrossRef]
2. J. Shi, J. Chen, Y. Li, Y. Zhu, G. Xu, and J. Xu, “Three-dimensional network electrolytes with highly efficient ion-transporting channels for quasi-solid-state dye-sensitized solar cells,” J. Power Sources 282, 51–57 (2015). [CrossRef]
3. Y. Huang, Y. Lu, Y. Lin, Y. Mao, G. Ouyang, H. Liu, S. Zhang, and Y. Tong, “Cerium-based hybrid nanorods for synergetic photo-thermocatalytic degradation of organic pollutants,” J. Mater. Chem. A 6(48), 24740–24747 (2018). [CrossRef]
4. P.-Y. Kuang, Y.-Z. Su, G.-F. Chen, Z. Luo, S.-Y. Xing, N. Li, and Z.-Q. Liu, “g-C3N4 decorated ZnO nanorod arrays for enhanced photoelectrocatalytic performance,” Appl. Surf. Sci. 358, 296–303 (2015). [CrossRef]
5. P.-Y. Kuang, Y.-Z. Su, K. Xiao, Z.-Q. Liu, N. Li, H.-J. Wang, and J. Zhang, “Double-Shelled CdS- and CdSe-Cosensitized ZnO Porous Nanotube Arrays for Superior Photoelectrocatalytic Applications,” ACS Appl. Mater. Interfaces 7(30), 16387–16394 (2015). [CrossRef]
6. P.-Y. Kuang, P.-X. Zheng, Z.-Q. Liu, J.-L. Lei, H. Wu, N. Li, and T.-Y. Ma, “Embedding Au Quantum Dots in Rimous Cadmium Sulfide Nanospheres for Enhanced Photocatalytic Hydrogen Evolution,” Small 12(48), 6735–6744 (2016). [CrossRef]
7. X. Li, S. Liu, K. Fan, Z. Liu, B. Song, and J. Yu, “MOF-Based Transparent Passivation Layer Modified ZnO Nanorod Arrays for Enhanced Photo-Electrochemical Water Splitting,” Adv. Energy Mater. 8(18), 1800101 (2018). [CrossRef]
8. H. Wang, F. Sun, Y. Zhang, K. Gu, W. Chen, and W. Li, “Photochemical construction of free-standing Sn-filled SnO2 nanotube array on a solution surface for flexible use in photocatalysis,” J. Mater. Chem. 21(33), 12407 (2011). [CrossRef]
9. L. Wei, C. Yu, Q. Zhang, H. Liu, and Y. Wang, “TiO2-based heterojunction photocatalysts for photocatalytic reduction of CO2 into solar fuels,” J. Mater. Chem. A 6(45), 22411–22436 (2018). [CrossRef]
10. Y. Zhang, J. Zhou, X. Chen, Q. Feng, and W. Cai, “MOF-derived C-doped ZnO composites for enhanced photocatalytic performance under visible light,” J. Alloys Compd. 777, 109–118 (2019). [CrossRef]
11. K. He, J. Xie, Z.-Q. Liu, N. Li, X. Chen, J. Hu, and X. Li, “Multi-functional Ni3C cocatalyst/g-C3N4 nanoheterojunctions for robust photocatalytic H2 evolution under visible light,” J. Mater. Chem. A 6(27), 13110–13122 (2018). [CrossRef]
12. L. Meng, S. Wang, F. Cao, W. Tian, R. Long, and L. Li, “Doping-Induced Amorphization, Vacancy, and Gradient Energy Band in SnS2 Nanosheet Arrays for Improved Photoelectrochemical Water Splitting,” Angew. Chem., Int. Ed. 58(20), 6761–6765 (2019). [CrossRef]
13. C. Peng, P. Wei, X. Li, Y. Liu, Y. Cao, H. Wang, H. Yu, F. Peng, L. Zhang, B. Zhang, and K. Lv, “High efficiency photocatalytic hydrogen production over ternary Cu/TiO2@Ti3C2Tx enabled by low-work-function 2D titanium carbide,” Nano Energy 53, 97–107 (2018). [CrossRef]
14. Y.-Q. Ye, G.-H. Gu, X.-T. Wang, T. Ouyang, Y. Chen, and Z.-Q. Liu, “3D cross-linked BiOI decorated ZnO/CdS nanorod arrays: A cost-effective hydrogen evolution photoanode with high photoelectrocatalytic activity,” Int. J. Hydrogen Energy 44(39), 21865–21872 (2019). [CrossRef]
15. G. H. Ahmed, J. K. El-Demellawi, J. Yin, J. Pan, D. B. Velusamy, M. N. Hedhili, E. Alarousu, O. M. Bakr, H. N. Alshareef, and O. F. Mohammed, “Giant Photoluminescence Enhancement in CsPbCl3 Perovskite Nanocrystals by Simultaneous Dual-Surface Passivation,” ACS Energy Lett. 3(10), 2301–2307 (2018). [CrossRef]
16. S. Pan, X. Zhang, W. Lu, and S. F. Yu, “Plasmon-engineered anti-replacement synthesis of naked Cu nanoclusters with ultrahigh electrocatalytic activity,” J. Mater. Chem. A 6(38), 18687–18693 (2018). [CrossRef]
17. Y. Yan, W. Kuang, L. Shi, X. Ye, Y. Yang, X. Xie, Q. Shi, and S. Tan, “Carbon quantum dot-decorated TiO2 for fast and sustainable antibacterial properties under visible-light,” J. Alloys Compd. 777, 234–243 (2019). [CrossRef]
18. K. Wang, Z. Jin, L. Liang, H. Bian, D. Bai, H. Wang, J. Zhang, Q. Wang, and S. Liu, “All-inorganic cesium lead iodide perovskite solar cells with stabilized efficiency beyond 15%,” Nat. Commun. 9(1), 4544 (2018). [CrossRef]
19. H. Sun, Y. Zhou, Y. Xin, K. Deng, L. Meng, J. Xiong, and L. Li, “Composition and Energy Band–Modified Commercial FTO Substrate for In Situ Formed Highly Efficient Electron Transport Layer in Planar Perovskite Solar Cells,” Adv. Funct. Mater. 29(11), 1808667 (2019). [CrossRef]
20. F. Cao, L. Meng, M. Wang, W. Tian, and L. Li, “Gradient Energy Band Driven High-Performance Self-Powered Perovskite/CdS Photodetector,” Adv. Mater. 31(12), 1806725 (2019). [CrossRef]
21. F. Cao, W. Tian, L. Meng, M. Wang, and L. Li, “Ultrahigh-Performance Flexible and Self-Powered Photodetectors with Ferroelectric P(VDF-TrFE)/Perovskite Bulk Heterojunction,” Adv. Funct. Mater. 29(15), 1808415 (2019). [CrossRef]
22. Q. Chen, J. Wu, X. Ou, B. Huang, J. Almutlaq, A. A. Zhumekenov, X. Guan, S. Han, L. Liang, Z. Yi, J. Li, X. Xie, Y. Wang, Y. Li, D. Fan, D. B. L. Teh, A. H. All, O. F. Mohammed, O. M. Bakr, T. Wu, M. Bettinelli, H. Yang, W. Huang, and X. Liu, “All-inorganic perovskite nanocrystal scintillators,” Nature 561(7721), 88–93 (2018). [CrossRef]
23. W. Pan, H. Wu, J. Luo, Z. Deng, C. Ge, C. Chen, X. Jiang, W.-J. Yin, G. Niu, L. Zhu, L. Yin, Y. Zhou, Q. Xie, X. Ke, M. Sui, and J. Tang, “Cs2AgBiBr6 single-crystal X-ray detectors with a low detection limit,” Nat. Photonics 11(11), 726–732 (2017). [CrossRef]
24. S. Yakunin, L. Protesescu, F. Krieg, M. I. Bodnarchuk, G. Nedelcu, M. Humer, G. De Luca, M. Fiebig, W. Heiss, and M. V. Kovalenko, “Low-threshold amplified spontaneous emission and lasing from colloidal nanocrystals of caesium lead halide perovskites,” Nat. Commun. 6(1), 8056 (2015). [CrossRef]
25. S. W. Eaton, M. Lai, N. A. Gibson, A. B. Wong, L. Dou, J. Ma, L. W. Wang, S. R. Leone, and P. Yang, “Lasing in robust cesium lead halide perovskite nanowires,” Proc. Natl. Acad. Sci. U. S. A. 113(8), 1993–1998 (2016). [CrossRef]
26. X. Du, G. Wu, J. Cheng, H. Dang, K. Ma, Y.-W. Zhang, P.-F. Tan, and S. Chen, “High-quality CsPbBr3 perovskite nanocrystals for quantum dot light-emitting diodes,” RSC Adv. 7(17), 10391–10396 (2017). [CrossRef]
27. H. Wang and D. H. Kim, “Perovskite-based photodetectors: materials and devices,” Chem. Soc. Rev. 46(17), 5204–5236 (2017). [CrossRef]
28. Y. Li, Z. Shi, L. Lei, Z. Ma, F. Zhang, S. Li, D. Wu, T. Xu, X. Li, C. Shan, and G. Du, “Controllable Vapor-Phase Growth of Inorganic Perovskite Microwire Networks for High-Efficiency and Temperature-Stable Photodetectors,” ACS Photonics 5(6), 2524–2532 (2018). [CrossRef]
29. R. Ahumada-Lazo, J. A. Alanis, P. Parkinson, D. J. Binks, S. J. O. Hardman, J. T. Griffiths, F. Wisnivesky Rocca Rivarola, C. J. Humphrey, C. Ducati, and N. J. L. K. Davis, “Emission Properties and Ultrafast Carrier Dynamics of CsPbCl3 Perovskite Nanocrystals,” J. Phys. Chem. C 123(4), 2651–2657 (2019). [CrossRef]
30. D. Chen, J. Li, X. Chen, J. Chen, and J. Zhong, “Grinding Synthesis of APbX3 (A = MA, FA, Cs; X = Cl, Br, I) Perovskite Nanocrystals,” ACS Appl. Mater. Interfaces 11(10), 10059–10067 (2019). [CrossRef]
31. Y. Li, Z.-F. Shi, X.-J. Li, and C.-X. Shan, “Photodetectors based on inorganic halide perovskites: Materials and devices,” Chin. Phys. B 28(1), 017803 (2019). [CrossRef]
32. S. Chu, S. Pan, and G. Li, “Trap state passivation and photoactivation in wide band gap inorganic perovskite semiconductors,” Phys. Chem. Chem. Phys. 20(39), 25476–25481 (2018). [CrossRef]
33. L. Protesescu, S. Yakunin, M. I. Bodnarchuk, F. Krieg, R. Caputo, C. H. Hendon, R. X. Yang, A. Walsh, and M. V. Kovalenko, “Nanocrystals of Cesium Lead Halide Perovskites (CsPbX3, X = Cl, Br, and I): Novel Optoelectronic Materials Showing Bright Emission with Wide Color Gamut,” Nano Lett. 15(6), 3692–3696 (2015). [CrossRef]
34. P. Gui, H. Zhou, F. Yao, Z. Song, B. Li, and G. Fang, “Space-Confined Growth of Individual Wide Bandgap Single Crystal CsPbCl3 Microplatelet for Near-Ultraviolet Photodetection,” Small 15(39), 1902618 (2019). [CrossRef]
35. Y. Chen, D. Feng, S. Xu, S. Zeng, and X. Wei, “Synthesis and photoluminescence of Eu2+ doped Lu2CaMg2Si3O12 garnet phosphors,” Mater. Lett. 164, 180–182 (2016). [CrossRef]
36. Y. Chen, X. Wu, S. Zeng, J. Li, and J. Lin, “Effect of alkali metal ions on structure and luminescent properties of red emitting -Ca3(PO4)2: Eu3+ phosphor,” J. Ceram. Soc. Jpn. 123(1434), 69–72 (2015). [CrossRef]
37. Y. Chen, C. Yang, M. Deng, J. He, Y. Xu, and Z.-Q. Liu, “A highly luminescent Mn4+ activated LaAlO3 far-red-emitting phosphor for plant growth LEDs: charge compensation induced Mn4+ incorporation,” Dalton Trans. 48(20), 6738–6745 (2019). [CrossRef]
38. X. Guo, J. He, M. Huang, R. Shi, Y. Chen, Y. Huang, J. Zhang, and Z.-Q. Liu, “Photoluminescence and thermal stability of Tb3+-doped K4SrSi3O9 phosphor with electron transition mechanisms,” Mater. Res. Bull. 118, 110523 (2019). [CrossRef]
39. X. Zhang, J. Zhang, Y. Chen, and M. Gong, “Energy transfer and multicolor tunable emission in single-phase Tb3+, Eu3+co-doped Sr3La(PO4)3 phosphors,” Ceram. Int. 42(12), 13919–13924 (2016). [CrossRef]
40. C. Li, Y. Li, T. Zhou, and R.-J. Xie, “Ultrasonic synthesis of Mn-doped CsPbCl3 quantum dots (QDs) with enhanced photoluminescence,” Opt. Mater. 94, 41–46 (2019). [CrossRef]
41. A. De, N. Mondal, and A. Samanta, “Luminescence tuning and exciton dynamics of Mn-doped CsPbCl3 nanocrystals,” Nanoscale 9(43), 16722–16727 (2017). [CrossRef]
42. Y. Gao, L. Zhao, Q. Shang, C. Li, Z. Liu, Q. Li, X. Wang, and Q. Zhang, “Photoluminescence properties of ultrathin CsPbCl3 nanowires on mica substrate,” J. Semicond. 40(5), 052201 (2019). [CrossRef]
43. G. Kresse and J. Furthmuller, “Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set,” Phys. Rev. B 54(16), 11169–11186 (1996). [CrossRef]
44. G. Kresse and J. Furthmuller, “Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set,” Comput. Mater. Sci. 6(1), 15–50 (1996). [CrossRef]
45. G. Kresse and D. Joubert, “From ultrasoft pseudopotentials to the projector augmented-wave method,” Phys. Rev. B 59(3), 1758–1775 (1999). [CrossRef]
46. J. P. Perdew, K. Burke, and M. Ernzerhof, “Generalized gradient approximation made simple,” Phys. Rev. Lett. 77(18), 3865–3868 (1996). [CrossRef]
47. H. J. Monkhorst and J. D. Pack, “Special points for Brillouin-zone integrations,” Phys. Rev. B 13(12), 5188–5192 (1976). [CrossRef]
48. Y. Rakita, N. Kedem, S. Gupta, A. Sadhanala, V. Kalchenko, M. L. Böhm, M. Kulbak, R. H. Friend, D. Cahen, and G. Hodes, “Low-Temperature Solution-Grown CsPbBr3 Single Crystals and Their Characterization,” Cryst. Growth Des. 16(10), 5717–5725 (2016). [CrossRef]
49. P. Zhang, S. Yu, X. Zhang, and S.-H. Wei, “Design of p-type transparent conductors from inverted band structure: The case of inorganic metal halide perovskites,” Phys. Rev. Mater. 3(5), 055201 (2019). [CrossRef]
50. Y. Zhai, X. Bai, G. Pan, J. Zhu, H. Shao, B. Dong, L. Xu, and H. Song, “Effective blue-violet photoluminescence through lanthanum and fluorine ions co-doping for CsPbCl3 perovskite quantum dots,” Nanoscale 11(5), 2484–2491 (2019). [CrossRef]
51. M. Ahmad, G. Rehman, L. Ali, M. Shafiq, R. Iqbal, R. Ahmad, T. Khan, S. Jalali-Asadabadi, M. Maqbool, and I. Ahmad, “Structural, electronic and optical properties of CsPbX3 (X = Cl, Br, I) for energy storage and hybrid solar cell applications,” J. Alloys Compd. 705, 828–839 (2017). [CrossRef]
52. O. N. Yunakova, V. K. Miloslavsky, E. N. Kovalenko, and V. V. Kovalenko, “Effect of structural phase transitions on the exciton absorption spectrum of thin CsPbCl3films,” Low Temp. Phys. 40(8), 690–693 (2014). [CrossRef]
53. S. Pan, Q. Liu, J. Zhao, and G. Li, “Ultrahigh Detectivity and Wide Dynamic Range Ultraviolet Photodetectors Based on BixSn1–xO2 Intermediate Band Semiconductor,” ACS Appl. Mater. Interfaces 9(34), 28737–28742 (2017). [CrossRef]
54. G. Maculan, A. D. Sheikh, A. L. Abdelhady, M. I. Saidaminov, M. A. Haque, B. Murali, E. Alarousu, O. F. Mohammed, T. Wu, and O. M. Bakr, “CH3NH3PbCl3 Single Crystals: Inverse Temperature Crystallization and Visible-Blind UV-Photodetector,” J. Phys. Chem. Lett. 6(19), 3781–3786 (2015). [CrossRef]
55. J. Zhang, Q. Wang, X. Zhang, J. Jiang, Z. Gao, Z. Jin, and S. Liu, “High-performance transparent ultraviolet photodetectors based on inorganic perovskite CsPbCl3 nanocrystals,” RSC Adv. 7(58), 36722–36727 (2017). [CrossRef]
56. X. Li, D. Yu, F. Cao, Y. Gu, Y. Wei, Y. Wu, J. Song, and H. Zeng, “Healing All-Inorganic Perovskite Films via Recyclable Dissolution–Recyrstallization for Compact and Smooth Carrier Channels of Optoelectronic Devices with High Stability,” Adv. Funct. Mater. 26(32), 5903–5912 (2016). [CrossRef]
57. T. Gao, Q. Zhang, J. Chen, X. Xiong, and T. Zhai, “Performance-Enhancing Broadband and Flexible Photodetectors Based on Perovskite/ZnO-Nanowire Hybrid Structures,” Adv. Opt. Mater. 5(12), 1700206 (2017). [CrossRef]
58. E. Zheng, B. Yuh, G. A. Tosado, and Q. Yu, “Solution-processed visible-blind UV-A photodetectors based on CH3NH3PbCl3 perovskite thin films,” J. Mater. Chem. C 5(15), 3796–3806 (2017). [CrossRef]
59. S. Pan, Z. Rao, Y. Wu, Z. Liu, J. Ge, and S. Zhang, “Ultrahigh detectivity ultraviolet photodetector based on orthorhombic phase CsPbI3 microwire using temperature self-regulating solar reactor,” Sol. Energy Mater. Sol. Cells 209, 110477 (2020). [CrossRef]
