全無機金屬鹵化物鈣鈦礦 (All-inorganic Pervoskite) 晶體材料為近幾年科學家們熱門著重研究的新興光電材料，歸因於材料本身不但具有優異的光吸收係數、優秀的電子遷移率、色純度高以及可調控之發光波長和能帶結構與能隙值、富含多元的材料形貌(由零維結構至三維結構) 等顯著特性，使得鈣鈦礦晶體材料在太陽能電池、量子點及發光二極體等領域應用具有極大的發展潛能與優勢。
本論文主要探討在單源熱蒸鍍製程中分別以兩種不同的蒸鍍製程蒸鍍不同厚度的薄膜，藉由石英振盪式膜厚監視器 (Deposition monitor) 進行膜厚監控，比較全無機金屬鹵化物鈣鈦礦 CsPbCl3 和 CsPbBr3 粉末與原料粉 CsCl、CsBr、PbCl2、PbBr2 蒸鍍之薄膜的成膜均勻性及發光情形，及進一步探討 CsPbCl3 在兩種不同蒸鍍製程不同的光學性質，再藉由 XRD、TEM 分析薄膜的晶體結構，佐以 UV-Vis、PL 分析各薄膜蒸鍍參數的光學性質。
綜合多樣分析結果，倘若蒸鍍製程從低溫開鍍至溫度 390℃，原料粉所蒸鍍之薄膜照 UV 燈皆無明顯發光，相較於全無機金屬鹵化物鈣鈦礦 CsPbCl3 和 CsPbBr3 隨蒸鍍膜厚的增加，照 UV 燈後有明顯不同波長的發光趨勢出現；若以高溫 390℃ 開鍍鈣鈦礦材料相比原料粉，有較為均勻之成膜和優異顯著的光學性質。
本研究以單源熱蒸鍍全無機金屬鹵化物鈣鈦礦 CsPbCl3 和 CsPbBr3 薄膜，再進行不同莫耳比例的摻雜，完成 CsPbCl3 (407nm) 至 CsPbBr3 (527nm)一系列可見光可調控波長及能帶位置，而當CsPbCl3：CsPbBr3 莫耳比為2：1 時PL 發射波長為453nm 處，符合學術界450nm 處至460nm 處的藍色發光研究，可利用此波長作為將來藍光LED 之應用。

Compares with solution processing, perovskite film prepared by single-source vacuum deposition were completely continuous and smooth. In this study, We turned our attention to single-source thermal evaporation to deposit all-inorganic perovskite film. To improve the quality of the perovskite thin film, we mixed CsCl and PbCl2 powder in the crucible to compare with CsPbCl3, CsPbBr3 powder. Therefore, we discuss the perovskite film in two different evaporation process : Start thermal evaporation from room temperature and Thermal evaporation begin at temperature390℃.
In the result, we found the perovskite film by Start thermal evaporation from room temperature process content more Pb in the thin film, and existed derivative CsPb2Cl5 phase. We used the XRD, TEM and UV-Vis to analyze perovskite film of different parameters. We doped CsPbBr3 in CsPbCl3 film and adjusted the different ratio of Br to tunable emission spectrum during the different evaporation process.
Finally, we fabricated high quality CsPbCl3 and CsPbBr3 film by thermal evaporation begins at temperature 390℃ and optimized in one batch, the corresponding PL evolution was investigated. When the CsPbCl3 and CsPbBr3 molar ratio is 2:1, the PL emission wavelength is at 452nm. This wavelength in line with the academic research of blue luminescence from 450nm to 460nm. This wavelength can be used as a blue LED application and compatible strategy for future LED industrialization.

[1] A. Kojima, K. Teshima, Y. Shirai, and T. Miyasaka, "Organometal halide perovskites as visible-light sensitizers for photovoltaic cells," Journal of the American Chemical Society, vol. 131, pp. 6050-6051, 2009.
[2] H.-S. Kim, C.-R. Lee, J.-H. Im, K.-B. Lee, T. Moehl, A. Marchioro, et al., "Lead iodide perovskite sensitized all-solid-state submicron thin film mesoscopic solar cell with efficiency exceeding 9%," Scientific reports, vol. 2, pp. 1-7, 2012.
[3] M. Kulbak, S. Gupta, N. Kedem, I. Levine, T. Bendikov, G. Hodes, et al., "Cesium enhances long-term stability of lead bromide perovskite-based solar cells," The journal of physical chemistry letters, vol. 7, pp. 167-172, 2016.
[4] G. Nedelcu, L. Protesescu, S. Yakunin, M. I. Bodnarchuk, M. J. Grotevent, and M. V. Kovalenko, "Fast anion-exchange in highly luminescent nanocrystals of cesium lead halide perovskites (CsPbX3, X= Cl, Br, I)," Nano letters, vol. 15, pp. 5635-5640, 2015.
[5] X. Li, Y. Wu, S. Zhang, B. Cai, Y. Gu, J. Song, et al., "CsPbX3 quantum dots for lighting and displays: room‐temperature synthesis, photoluminescence superiorities, underlying origins and white light‐emitting diodes," Advanced Functional Materials, vol. 26, pp. 2435-2445, 2016.
[6] Q. Pan, H. Hu, Y. Zou, M. Chen, L. Wu, D. Yang, et al., "Microwave-assisted synthesis of high-quality “all-inorganic” CsPbX 3 (X= Cl, Br, I) perovskite nanocrystals and their application in light emitting diodes," Journal of Materials Chemistry C, vol. 5, pp. 10947-10954, 2017.
[7] J. Song, J. Li, X. Li, L. Xu, Y. Dong, and H. Zeng, "Quantum dot light‐emitting diodes based on inorganic perovskite cesium lead halides (CsPbX3)," Advanced materials,vol. 27, pp. 7162-7167, 2015.
[8] G. Li, F. W. R. Rivarola, N. J. Davis, S. Bai, T. C. Jellicoe, F. de la Peña, et al., "Highly efficient perovskite nanocrystal light‐emitting diodes enabled by a universal crosslinking method," Advanced materials, vol. 28, pp. 3528-3534, 2016.
[9] P. Liu, W. Chen, W. Wang, B. Xu, D. Wu, J. Hao, et al., "Halide-rich synthesized cesium lead bromide perovskite nanocrystals for light-emitting diodes with improved performance," Chemistry of Materials, vol. 29, pp. 5168-5173, 2017.
[10] N. K. Kumawat, X.-K. Liu, D. Kabra, and F. Gao, "Blue perovskite light-emitting diodes: progress, challenges and future directions," Nanoscale, vol. 11, pp. 2109-2120, 2019.
[11] M. Cao, Y. Xu, P. Li, Q. Zhong, D. Yang, and Q. Zhang, "Recent advances and perspectives on light emitting diodes fabricated from halide metal perovskite
nanocrystals," Journal of Materials Chemistry C, vol. 7, pp. 14412-14440, 2019.
[12] F. Chen, Q. Lin, H. Shen, and A. Tang, "Blue quantum dot-based electroluminescent light-emitting diodes," Materials Chemistry Frontiers, vol. 4, pp. 1340-1365, 2020.
[13] G. Li, J. Huang, Y. Li, J. Tang, and Y. Jiang, "Highly bright and low turn-on voltage CsPbBr3 quantum dot LEDs via conjugation molecular ligand exchange," Nano Research, vol. 12, pp. 109-114, 2019.
[14] J. Pan, L. N. Quan, Y. Zhao, W. Peng, B. Murali, S. P. Sarmah, et al., "Highly efficient perovskite‐quantum‐dot light‐emitting diodes by surface engineering," Advanced Materials, vol. 28, pp. 8718-8725, 2016.
[15] E. P. Yao, Z. Yang, L. Meng, P. Sun, S. Dong, Y. Yang, et al., "High‐Brightness Blue and White LEDs based on Inorganic Perovskite Nanocrystals and their Composites," Advanced Materials, vol. 29, p. 1606859, 2017.
[16] Y.-H. Suh, T. Kim, J. W. Choi, C.-L. Lee, and J. Park, "High-performance CsPbX3 perovskite quantum-dot light-emitting devices via solid-state ligand exchange," ACS Applied Nano Materials, vol. 1, pp. 488-496, 2018.
[17] A. Dutta, R. K. Behera, S. K. Dutta, S. Das Adhikari, and N. Pradhan, "Annealing CsPbX3 (X= Cl and Br) perovskite nanocrystals at high reaction temperatures: phase change and its prevention," The journal of physical chemistry letters, vol. 9, pp.
6599-6604, 2018.
[18] M. K. Gangishetty, S. Hou, Q. Quan, and D. N. Congreve, "Reducing architecture limitations for efficient blue perovskite light‐emitting diodes," Advanced Materials, vol. 30, p. 1706226, 2018.
[19] Y. Tan, Y. Zou, L. Wu, Q. Huang, D. Yang, M. Chen, et al., "Highly luminescent and stable perovskite nanocrystals with octylphosphonic acid as a ligand for efficient light-emitting diodes," ACS applied materials & interfaces, vol. 10, pp. 3784-3792, 2018.
[20] J. Song, J. Li, L. Xu, J. Li, F. Zhang, B. Han, et al., "Room‐temperature triple‐ligand surface engineering synergistically boosts ink stability, recombination dynamics, and charge injection toward EQE‐11.6% perovskite QLEDs," Advanced Materials, vol. 30, pp. 1800764, 2018.
[21] N. Pradhan, "Tips and Twists in Making High Photoluminescence Quantum Yield Perovskite Nanocrystals," ACS Energy Letters, vol. 4, pp. 1634-1638, 2019.
[22] B.-B. Zhang, S. Yuan, J.-P. Ma, Y. Zhou, J. Hou, X. Chen, et al., "General mild reaction creates highly luminescent organic-ligand-lacking halide perovskite
nanocrystals for efficient light-emitting diodes," Journal of the American Chemical Society, vol. 141, pp. 15423-15432, 2019.
[23] Z. Li, Z. Chen, Y. Yang, Q. Xue, H.-L. Yip, and Y. Cao, "Modulation of recombination zone position for quasi-two-dimensional blue perovskite light-emitting diodes with efficiency exceeding 5%," Nature communications, vol. 10, pp. 1-10, 2019.
[24] H. Shao, Y. Zhai, X. Wu, W. Xu, L. Xu, B. Dong, et al., "High brightness blue light-emitting diodes based on CsPb (Cl/Br) 3 perovskite QDs with phenethylammonium chloride passivation," Nanoscale, vol. 12, pp. 11728-11734, 2020.
[25] Y. Wu, X. Li, and H. Zeng, "Highly luminescent and stable halide perovskite nanocrystals," ACS Energy Letters, vol. 4, pp. 673-681, 2019.
[26] X. Zheng, Y. Hou, H.-T. Sun, O. F. Mohammed, E. H. Sargent, and O. M. Bakr, "Reducing Defects in Halide Perovskite Nanocrystals for Light-Emitting Applications," The journal of physical chemistry letters, vol. 10, pp. 2629-2640, 2019.
[27] Z.-J. Yong, S.-Q. Guo, J.-P. Ma, J.-Y. Zhang, Z.-Y. Li, Y.-M. Chen, et al., "Doping-enhanced short-range order of perovskite nanocrystals for near-unity violet
luminescence quantum yield," Journal of the American Chemical Society, vol. 140, pp. 9942-9951, 2018.
[28] S. Hou, M. K. Gangishetty, Q. Quan, and D. N. Congreve, "Efficient blue and white perovskite light-emitting diodes via manganese doping," Joule, vol. 2, pp. 2421-2433, 2018.
[29] N. Mondal, A. De, and A. Samanta, "Achieving near-unity photoluminescence efficiency for blue-violet-emitting perovskite nanocrystals," ACS Energy Letters, vol. 4, pp. 32-39, 2018.
[30] A. De, S. Das, N. Mondal, and A. Samanta, "Highly Luminescent Violet-and Blue-Emitting Stable Perovskite Nanocrystals," ACS Materials Letters, vol. 1, pp.
116-122, 2019.
[31] G. Pan, X. Bai, W. Xu, X. Chen, Y. Zhai, J. Zhu, et al., "Bright Blue Light Emission of Ni2+ Ion-Doped CsPbCl x Br3–x Perovskite Quantum Dots Enabling Efficient Light-Emitting Devices," ACS Applied Materials & Interfaces, vol. 12, pp. 14195-14202, 2020.
[32] H. Wang, Y. Xu, J. Wu, L. Chen, Q. Yang, B. Zhang, et al., "Bright and Color-Stable Blue-Light-Emitting Diodes based on Three-Dimensional Perovskite Polycrystalline Films via Morphology and Interface Engineering," The Journal of Physical Chemistry Letters, vol. 11, pp. 1411-1418, 2020.
[33] T. Chiba, J. Sato, S. Ishikawa, Y. Takahashi, H. Ebe, S. Sumikoshi, et al., "Neodymium Chloride-Doped Perovskite Nanocrystals for Efficient Blue Light-Emitting Devices," ACS Applied Materials & Interfaces, vol. 12, pp. 53891-53898, 2020.
[34] J. Lei, F. Gao, H. Wang, J. Li, J. Jiang, X. Wu, et al., "Efficient planar CsPbBr3 perovskite solar cells by dual-source vacuum evaporation," Solar Energy Materials
and Solar Cells, vol. 187, pp. 1-8, 2018.
[35] L. Yang, W.-L. Tsai, C.-S. Li, B.-W. Hsu, C.-Y. Chen, C.-I. Wu, et al., "High-Quality Conformal Homogeneous All-Vacuum Deposited CsPbCl3 Thin Films and Their UV Photodiode Applications," ACS Applied Materials & Interfaces, vol. 11, pp. 47054-47062, 2019.
[36] Y. El Ajjouri, F. Palazon, M. Sessolo, and H. J. Bolink, "Single-source vacuum deposition of mechanosynthesized inorganic halide perovskites," Chemistry of Materials, vol. 30, pp. 7423-7427, 2018.
[37] P. Du, J. Li, L. Wang, J. Liu, S. Li, N. Liu, et al., "Vacuum-deposited blue inorganic perovskite light-emitting diodes," ACS Applied Materials & Interfaces, vol. 11, pp. 47083-47090, 2019.
[38] L. Bai, S. Wang, Y. Zhang, K. Zhang, H. Li, K. Ou, et al., "Investigation on violet/blue all-inorganic light-emitting diodes based on CsPbCl3 films," Journal of
Luminescence, p. 117422, 2020.