本論文，我們採取摻雜一種二維鈣鈦礦材料－苯乙銨，將其加入三維鈣鈦礦之發光層中，而形成的結構普遍稱為Ruddlesden–Popper，也稱之為準二維鈣鈦礦。首先，純三維鈣鈦礦之表現目前偏差，歸因於其表面粗糙度過高以及缺陷過多的問題，會導致漏電流過大，嚴重影響元件操作時之亮度以及發光效率上的表現。
因此，本論文透過摻雜苯乙銨到三維鈣鈦礦之中，摻雜二維鈣鈦礦到前驅液裡使之成為表面活性劑，可以在薄膜形成的過程當中有效地限制住三維鈣鈦礦晶粒的成長，從而達到表面平滑以及減少缺陷的效果。
除此之外，本論文還摻雜聚乙烯吡咯烷酮－polyvinylpyrrolidone (PVP)，由於其擁有親水性的特質，因此加入PVP可以促使前驅液的附著力更佳，從而減少表面缺陷並且提升膜況品質。最終，再藉由退火溫度的改變，求得最佳化的狀態。本論文透過以上方式達到不錯的表現，最大亮度為14482 cd m−2，而電流效率為2.4 cd A-1。

In recent years, organic-inorganic perovskite light-emitting diodes have highly attracted great research interest for use in optoelectronics, on account of their instinct features, for instance, high color purity, tunable bandgap as well as simple fabrication. However, since three-dimensional perovskites have bigger grain sizes, which would cause inferior roughness of surface and pinholes on the films. Therefore, the problems have been improved recently. Herein, a type of two-dimensional perovskite－phenethylammonium (PEA),which we added into the 3D perovskite precursor solution, then the small grains would reduce the dimensionality, which starts a transition from 3D perovskites to layered perovskites, that is to say, Ruddlesden–Popper structure.
First of all, the performance of 3D perovskites is not satisfactory currently, which is attributed to inferior roughness of surface and many defects on the films, then resulting in high leakage current, low brightness and low current efficiency. In consequence, we dope PEA into 3D perovskite precursor solution, which acts as a surfactant that can efficiently constrain the growth of 3D perovskite grains when the films form, impeding the growth of 3D perovskite grains and efficiently decreases film roughness. In addition, we also dope polyvinylpyrrolidone ( PVP ), a hydrophilic polymer, into the quasi-2D perovskites precursor solution. Owing to the precursor solution whose wettability increased, the surface coverage of PEA2MA2Pb3Br10 with PVP composite films without pinholes would be produced. To sum up, electrically driven perovskite light emitting diodes at optimized annealing temperature were fabricated to exhibit good brightness and current efficiency. For example, the perovskite light emitting diode exhibits the brightness of 14482 cd m−2 and the current efficiency of 2.4cd A-1.

[1] J. Wang , N. Wang , Y. Jin , J.S. , Z.K. Tan , H. Du , L. Cheng , X. Dai , S. Bai , H. He , Z. Ye , M. L. Lai , R. H. Friend , and W. Huang ,“Interfacial Control Toward Efficient and Low-Voltage Perovskite Light-Emitting Diodes ,” Adv. Mater.,vol. 27,pp. 2311–2316, Feb.2015
[2] N. A. Lee, G. E. Gilligan, J. Rochford, "Solar Energy Conversion," Green Chemistry, pp. 881-918, Nov.2017
[3] D. Weber, "CH3NH3PbX3, ein Pb(II)-System mit kubischer Perowskitstruktur / CH3NH3PbX3, a Pb(II)-System with Cubic Perovskite Structure," Z. Naturforsch, vol. 33, no. 12, pp. 1443-1445, Dec. 1978.
[4] D. Weber, "CH3NH3SnBrxl3 x (x = 0-3), ein Sn(II)-System mit kubischer Perowskitstruktur," Z. Naturforsch, vol. 33b, pp. 862-865, Aug 1978.
[5] National Renewable Energy Laboratory, "Best Research-Cell Efficiency Chart," 2019. [Online].Available:https://www.nrel.gov/pv/assets/pdfs/best-research-cell-efficiencies.20190703.pdf.
[6] D. B. Mizti, "Organic−Inorganic Perovskites Containing Trivalent Metal Halide Layers:  The Templating Influence of the Organic Cation Layer," Inorg. Chem., vol. 39, no. 26, pp. 6107-6113, Dec .2000.
[7] D. B. Mizti, "Templating and Structural Engineering in Organic-Inorganic Perovskites," J. Chem. Soc., Dalton Trans, no. 1, pp. 1-12, Dec.2000.
[8] A. Kojima, ,K. Teshima , T.Miyasaka, ,Y. Shirai , "Novel Photoelectrochemical Cell with Mesoscopic Electrodes Sensitized by Lead-Halide Compounds (2)," T Electrochem Soc., pp. 397, Oct. 2006.
[9] M. A. Green, Y .Hishikawa, E. D. Dunlop, D. H. Levi, J. H. Ebinger, "Solar Cell Efficiency Tables (version 51)," Prog photovltaics, vol. 26, no. 1, pp. 3-12, Jan. 2018.
[10] T. M. Koh, V. Shanmugam, J. Schlipf, L. Oesinghaus, P. M¨uller-Buschbaum, N. Ramakrishnan, V. Swamy, N. Mathews, P. P. Boix and S. G. Mhaisalkar, " Nanostructuring Mixed-Dimensional Perovskites: A Route Toward Tunable, Efficient Photovoltaics," Adv. Mater.,vol. 28,pp. 3653–3661,May.2016
[11] R. Hamaguchi, M. Yoshizawa-Fujita, T. Miyasaka, H. Kunugita, K. Ema, Y. Takeoka and M. Rikukawa, " Formamidine and Cesium-Based Quasi-Two-Dimensional Perovskites as Photovoltaic Absorbers," Chem. Commun.,vol 53,pp. 4366,Mar.2017
[12] C. C. Stoumpos, D. H. Cao, D. J. Clark, J. Young, J. M. Rondinelli, J. I. Jang, J. T. Hupp and M. G. Kanatzidis, " Ruddlesden–Popper Hybrid Lead Iodide Perovskite 2D Homologous Semiconductors," Chem. Mater., vol.28,pp. 2852–2867,Apr.2016
[13] Z. Yang, L. Yang, G. Wu, M. Wang and H. Chen, " A Heterojunction Based on Well-ordered Organic-Inorganic Hybrid Perovskite and Its Photovoltaic Performance," Acta Chim. Sin.,vol. 69,pp. 627–632,Mar.2011
[14] J. Liu, J. Leng, K. Wu, J. Zhang and S. Jin, " Observation of Internal Photoinduced Electron and Hole Separation in Hybrid Two-Dimentional Perovskite Films," J. Am. Chem. Soc.,vol. 139,pp. 1432, Jan.2017
[15] D. Ma, Y. Fu, L. Dang, J. Zhai, I. A. Guzei and S. Jin, " Single-Crystal Microplates of Two-Dimensional Organic–Inorganic Lead Halide Layered Perovskites for Optoelectronics," Nano Res., vol.10, pp.2117–2129,Jan.2017
[16] K. Yao, X. Wang, Y. Xu, F. Li and L. Zhou, " Multilayered Perovskite Materials Based on Polymeric-Ammonium Cations for Stable Large-Area Solar Cell," Chem. Mater., vol.28,pp. 3131–3138,Apr.2016
[17] T. Zhang, L. Xie, L. Chen, N. Guo, G. Li, Z. Tian, B. Mao and Y. Zhao, " In Situ Fabrication of Highly Luminescent Bifunctional Amino Acid Crosslinked 2D/3D NH3C4H9COO(CH3NH3PbBr3)n Perovskite Films," Adv. Funct. Mater.,vol. 27,pp. 1603568, Oct.2016
[18] J. F. Liao, H. S. Rao, B. X. Chen, D. B. Kuang and C. Y. Su, " Dimension Engineering on Cesium Lead Iodide for Efficient and Stable perovskite Solar Cells," J. Mater. Chem. , vol.5, pp.2066–2072, Dec.2016
[19] Z. Xiao, Ross A. Kerner, L. Zhao, Nhu L. Tran, K. Min Lee, T. Koh, G. D. Scholes and B. P. Rand, “Efficient Perovskite Light-Emitting Diodes Featuring Nanometre-Sized Crystallites,” Nature Photonic , vol 11 ,pp. 108-115, Feb.2017
[20] Y. Tian, C. Zhou, M. Worku, X. Wang, Y. Ling, H. Gao, Y. Zhou, Y. Miao, J. Guan, and B. Ma, “Highly Efficient Spectrally Stable Red Perovskite Light Emitting Diodes,” Adv. Mater., vol.30, pp.1707093,Mar.2018
[21] 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,Jan.2019
[22] Y. Kim,S. Baek, J. Myoung, “Enhanced Brightness of Methylammonium Lead Tribromide Perovskite Microcrystal-based Green Light-Emitting Diodes by Adding Hydrophilic Polyvinylpyrrolidone with Oleic Cid-modified ZnO Quantum Dot Electron Transporting Layer,” Journal of Alloys and Compounds ,vol.786,pp. 11-17 ,May.2019
[23] L. Zhang, C. Sun , T. He , Y. Jiang , J. Wei, Y. Huang and M. Yuan, “High-performance Quasi-2D Perovskite Light-Emitting Diodes: from Materials to Devices,” Science & Applications ,vol.10 ,pp.61-86,Mar.2021
[24] J. C. Yu , D. W. Kim , D. B. Kim , E. D. Jung , J. H. Park , A.Y. Lee , B. R. Lee , D. D. Nuzzo , R. H. Friend , and M. H. Song , “Improving the Stability and Performance of Perovskite Light-Emitting Diodes by Thermal Annealing Treatment,” Adv. Mater., vol.28, pp.6906–6913,May.2016
[25] W. Feng, K. Lin, W. Li, X. Xiao, J. Lu, C. Yan, X.Liu, L. Xie, C. Tian, D. Wu, K. Wang and Z. Wei," Efficient All-Inorganic Perovskite Light-Emitting Diodes Enabled by Manipulating the Crystal Orientation," Mater. Chem.,vol. 9, pp.11064–11072,Apr. 2021
[26] Q. Xu, F. Wang, Z. Tan, L. Li, S. Li, X. Hou, G. Sun, X. Tu, J. Hou and Y. Li, "High-Performance Polymer Solar Cells with Solution-Processed and Environmentally Friendly CuOx Anode Buffer Layer," ACS Appl. Mater. Interfaces., vol. 5, no. 21, Oct 2013.
[27] D. Liu, Y. Li, J. Yuan, Q. Hong, G. Shi, D. Yuan, J. Wei, C. Huang, J. Tang, M.-K. Fung, "Improved Performance of Inverted Planar Perovskite Solar Cells with F4-TCNQ Doped PEDOT:PSS Hole Transport Layers," J. Mater. Chem. A, vol. 5, no. 12, pp. 5701-5708, Jan 2017.
[28] J. Y. Jeng, Y. F. Chiang, M. H. Lee, S. R. Peng, T. F. Guo, P. Chen and T. C. Wen, "CH3NH3PbI3 Perovskite/Fullerene Planar-Heterojunction Hybrid Solar Cells," Adv. Mater., vol. 25, no. 27, pp. 3727-3732, Jul 2013.
[29] [Online]. Available:https://en.wikipedia.org/wiki/Buckminsterfullerene.
[30] D. H. Cao, C. C. Stoumpos, T. Yokoyama, J. L. Logsdon, T.-B. Song, O. K. Farha, M. R. Wasielewski, J. T. Hupp, M. G. Kanatzidis, " Thin Films and Solar Cells Based on Semiconducting Two-Dimensional Ruddlesden–Popper (CH3(CH2)3NH3)2(CH3NH3)n−1SnnI3n+1 Perovskites," ACS Energy Lett., vol.2,pp. 982-990,Apr.2017
[31] J. Zhang, L. Zhang, X. Li, X. Zhu, J. Yu, K. Fan, “Binary Solvent Engineering for High-Performance Two-Dimensional Perovskite Solar Cells,” ACS Sustainable Chem. Eng., vol.7, pp. 3487−3495,Jan.2019
[32] Mitzi, D., Wang, S., Feild, C., Chess, C. and Guloy, A. ,"Conducting Layered Organic-Inorganic Halides Containing-Oriented Perovskite Sheets," Science ,vol.267, pp.1473–1476,Mar.1995.
[33] Z.K. Tan, R. S. Moghaddam, M. L. Lai, P. Docampo, R. Higler, F. Deschler, M. Price, A. Sadhanala, L. M. Pazos, D. Credgington, F. Hanusch, T. Bein, H. J. Snaith and R. H. Friend," Bright Light-Emitting Diodes Based on Organometal Halide Perovskite," Nature Nanotechnology, vol 9, pp.687–692,Aug. 2014
[34] H. Cho, S.H. Jeong, M.H. Park, Y.H. Kim, C. Wolf, C.L. Lee, J. H. Heo," Overcoming the Electroluminescence Efficiency Limitations of Perovskite Light-Emitting Diodes," Science,vol 350,pp.1222-1225, Dec. 2015
[35] G. Li, Z.K. Tan, D.Di, M. L. Lai, L. Jiang, J. H.W. Lim, R. H. Friend, and N. C. Greenham," Efficient Light-Emitting Diodes Based on Nanocrystalline Perovskite in a Dielectric Polymer Matrix," Nano , vol.15, pp.2640−2644,Feb.2014
[36] J. Xing , Y. Zhao, M. Askerka, L.N. Quan , X. Gong , W. Zhao , J. Zhao , H. Tan , G. Long , L. Gao, Z.Yang , O. Voznyy , J. Tang , Z.H. Lu , Q. Xiong and E. H. Sargent," Color-Stable Highly Luminescent Sky-Blue Perovskite Light-Emitting Diodes," Nature Communications , vol.9, pp.3541,Aug.2018
[37] J. A. Sichert, Yu Tong, N. Mutz, M. Vollmer,S. Fischer, K. Z. Milowska, R. G. Cortadella, B. Nicke, C. C. Daw, J. K. Stolarczyk, A. S. Urban, and J. Feldmann ," Quantum Size Effect in Organometal Halide Perovskite Nanoplatelets," Nano, vol.15,pp. 6521−6527,Sep.2015
[38] L. Zhao, K. M. Lee, K. Roh, S. U. Z. Khan, and B. P. Rand, “Improved Outcoupling Efficiency and Stability of Perovskite Light-Emitting Diodes Using Thin Emitting Layers,” Adv. Mater., vol.31,pp. 1805836,Nov.2018
[39] P. Du, J. Li, L. Wang, J. Liu, S. Li, N. Liu, Y. Li, M. Zhang, L. Gao, Y. Ma, and J. Tang," Vacuum-Deposited Blue Inorganic Perovskite Light-Emitting Diodes," ACS Appl. Mater. Interfaces , vol.11,pp. 47083−47090,Nov.2019
[40] M. Liu , M.l B. Johnston and H. J. Snaith," Efficient Planar Heterojunction Perovskite Solar Cells by Vapour Deposition," Nature vol.501 , pp.395-402,Sep.2013
[41] C. Yan, K. Lin, J. Lu and Z. Wei," Composition Engineering to Obtain Efficient Hybrid Perovskite Light-Emitting Diodes," Frontiers of Optoelectronics ,vol. 13, pp.282–290 ,Aug.2020
[42] J.-C. Blancon, H. Tsai, W. Nie, C. C. Stoumpos, L. Pedesseau, C. Katan,
M. Kepenekian, C. M. M. Soe, K. Appavoo, M. Y. Sfeir, S. Tretiak,1 P. M. Ajayan,
M. G. Kanatzidis, J. Even, J. J. Crochet, A. D. Mohite," Extremely Efficient Internal Exciton Dissociation through Edge States in Layered 2D Perovskites," Science ,vol.355, pp.1288–1292,Mar. 2017
[43] K. Lin , J. Xing , L. N. Quan, F. P. G. Arquer, X. Gong, J. Lu , L. Xie , W.Zhao , D. Zhang , C. Yan , W. Li , X.Liu , Y. Lu , J. Kirman, E.H. Sargent, Q. Xiong and Z. Wei," Perovskite Light-Emitting Diodes with External Quantum Efficiency Exceeding 20 Percent ," Nature, vol. 562, ,pp.245-259, Oct. 2018
[44] X. Zhang, H. Liu, W. Wang, J. Zhang, B. Xu, K. L. Karen, Y. Zheng, S. Liu, S. Chen, K. Wang, and X. W. Sun," Hybrid Perovskite Light-Emitting Diodes Based on Perovskite Nanocrystals with Organic–Inorganic Mixed Cations ," Adv. Mater., vol.29, pp.1606405,Mar.2017
[45] M. Li, J. Wang, C. Mai, Y. Cun, B. Zhang, G. Huang, D. Yu, J. Li,A. Mu, L. Cao, D. Li, J. Wang, J. Wang and J. Peng , “Bifacial Passivation towards Efficient FAPbBr3-based Inverted Perovskite Light-Emitting Diodes,” Nanoscale, vol.12, pp.14724–14732, Jun.2020
[46] Y. Ahn, S. Lee, D.H. Kwak, M. Kim, D. Y. Kim,J. Kim, Y. Park, M. C. Suh , “Improving the Efficiency of Perovskite Light Emitting Diode Using Polyvinylpyrrolidone as an Interlayer,” Applied Surface Science vol.507 ,pp.145071,Mar.2020
[47] W. Chen, Y. Wua, B. Tu, F. Liu, A. B. Djurišic´, and Z. He, “Inverted Planar Organic-Inorganic Hybrid Perovskite Solar Cells with NiOx Hole-Transport Layers as Light-in Window,” Applied Surface Science vol.451 ,pp.325–332,2018
[48] P. L. Qin, Q. He, C. Chen, X.L. Zheng, G. Yang, H. Tao, L.B. Xiong, L. Xiong, G. Li, and G.J. Fang, “High-Performance Rigid and Flexible Perovskite Solar Cells with Low-Temperature Solution-Processable Binary Metal Oxide Hole-Transporting Materials,” Sol., vol.1, pp.1700058.,Jul.2017
[50] T. Zhang, L. Xie, L. Chen, N. Guo, G. Li, Z. Tian, B. Mao, and Y. Zhao , "In Situ Fabrication of Highly Luminescent Bifunctional Amino Acid Crosslinked 2D/3D NH3C4H9COO(CH3NH3PbBr3)n Perovskite Films," Adv. Funct. Mater., 27, pp.1603568,Oct.2016
[51] D. Liu, Y. Li, J. Yuan, Q. Hong, G. Shi, D. Yuan, J. Wei, C. Huang, J. Tang, M.-K. Fung, "Improved Performance of Inverted Planar Perovskite Solar Cells with F4-TCNQ Doped PEDOT:PSS Hole Transport Layers," J. Mater. Chem., vol. 5, no. 12, pp. 5701-5708, Jan 2017.
[52] [Online]. Available:https://en.wikipedia.org/wiki/Buckminsterfullerene.
[53] R. Wang , Y. Zhang , F.X. Yu , Y. Dong , Y.L. Jia , X.J. Ma , Q. Xu , Y. Deng , Z.H. Xiong , C.H. Gao, “An Efficient CsPbBr3 Perovskite Light-Emitting Diode by Employing 1,3,5-tri (m-pyrid-3-yl-phenyl)benzene as a Hole and Exciton Blocking Layer,” Journal of Luminescence vol.219, pp.116915 ,Mar.2020