近年來，三維有機-無機鹵化物鈣鈦礦材料因高吸收係數、低激子束縛能和高載子擴散長度與載子遷移率等諸多優點，使得鈣鈦礦材料在各個領域上都有突出的表現，尤其在太陽能電池領域下才短短的幾年內，效率已由3.8 %[1]提升至24.2 %[2]。但是它們對於水氣、光和高溫表現出差的穩定性，使其無法達到商業化的門檻。為了獲得更加穩定的鈣鈦礦，科學藉由長碳鏈有機胺將鈣鈦礦分隔開來，降低了水氣與鈣鈦礦反應降解的機率，並形成具有多量子井效應的二維有機-無機Ruddlesden-Popper鈣鈦礦(OIRPP)。然而，因為有機絕緣層的關係，使其載子傳輸受到限制。為了獲得高穩定性和較好的載子遷移率，在本研究中我們使用烯炳胺(Allylamine)來代替現有的長碳鏈間隔物，希望藉由烯丙胺的短碳鏈和雙鍵效應改善絕緣有機層所帶來的影響，並搭配我們團隊所提出的恆溫緩慢揮發溶劑成長法(SECT)，合成出高品質毫米級大小的Ruddlesden-Popper鈣鈦礦晶體，此外我們還藉由調控反應中甲胺(Methylamine)與烯丙胺之間的比例，成功的獲得不同層數(n = 1, 2 )。由X-光粉末繞射圖中清楚看到單一層數的等間距繞射峰，為了確認其晶格結構為Ruddlesden-Popper相，我們還通過密度泛函理論獲得理論的X-光粉末繞射圖譜並進行比對。此外，由螢光光譜得知其放射波長分別為512.4 nm (n = 1)和 579.9 nm (n = 2)，並由Tauc圖計算出其能隙大小為2.32 eV (n = 1)、2.09 eV (n = 2)。接著我們還將其與相對應的三維鈣鈦礦和正丁胺、苯乙胺間隔物的單晶做比較，發現含有烯丙胺間隔物的二維Ruddlesden-Popper鈣鈦礦同樣具有極高的穩定性。最後，為了後續元件的製程，我們開始嘗試將我們所合成的晶體回溶至二甲基甲醯胺和二甲基亞碸中並進行塗膜，由X-光粉末繞射圖，證實此方法得到之薄膜具有高度均質性，改善了以往利用莫爾數比來塗膜時常發生混相之缺點。

In recent years, three-dimensional organic-inorganic halide perovskite materials shown several promising properties, such as high absorption coefficient, low exciton binding energy, large carrier diffusion length and high carrier mobility. Based on these outstanding properties, they are considered as next generation materials for solar cells (power conversion efficiency achieved 24.2%[2]). However, the commercial perovskite solar cells are lacking due to they displayed poor stability under moisture, illumination, and high thermal. To obtain long term stability perovskite, scientists slice organic long carbon chain molecules into 3D perovskite slabs to demonstrate phase stable two-dimensional organic-inorganic hybrid Ruddlesden-Popper perovskite (OIRPP) with quantum well structure. However, the electrical properties in OIRPP are displayed limit due to long carbon chains are insulator. In order to obtain long term stability and better carriers transport, in this study, we mainly use the short carbon chain and π-π interaction of allylamine to replace original long carbon chain spacers. We use slow evaporation at constant temperature solution-growth method to synthesize high quality millimeter-sized OIRPP crystal with allylamine, and obtained different n-value ( n = 1, 2 ) by different ratio of methylamine to allylamine. In the XRD measurements, the patterns show clear repeating unit peak without any mixed n values. To confirm the structure OIRPP with allylamine, we also obtain similar XRD patterns from simulation by density functional theory (DFT). Moreover, the bandgaps of OIRPP are 2.32 eV (n = 1) and 2.09 eV (n = 2), and the emission peaks are at 512.4 nm (n =1) and 579.9 nm (n = 2). In XRD measurements, the stability of OIRPP with allylamine display superior stability than 3D organic inorganic hybrid perovskite. Finally, in order to fabricate optoelectronic devices, we also dissolve the single crystals in DMF and DMSO to fabricate pure phase OIRPP thin films with similar repeating unit. The thin films exhibit pure n value compared to traditional method which dissolve from the precursor powder.

1. Kojima, A.; Teshima, K.; Shirai, Y.; Miyasaka, T., Organometal halide perovskites as visible-light sensitizers for photovoltaic cells. J Am Chem Soc 2009, 131 (17), 6050-6051.
2. Best Research-Cell efficiency chart, < https://www.nrel.gov/pv/cell-efficiency.html > 2018.
3. Adjokatse, S.; Fang, H. H.; Loi, M. A., Broadly tunable metal halide perovskites for solid-state light-emission applications. Materials Today 2017, 20 (8), 413-424.
4. Grancini, G.; Nazeeruddin, M. K., Dimensional tailoring of hybrid perovskites for photovoltaics. Nature Reviews Materials 2018, 4 (1), 4-22.
5. Guyot, F.; Richet, P.; Courtial, P.; Gillet, P., High-temperature heat capacity and phase transitions of CaTiO3 perovskite. Physics and Chemistry of Minerals 1993, 20 (3), 141-146.
6. Degtyareva, V.; Verba, L. I., Activity of the raw material and the firing conditions as factors in the sintering and growth of calcium titanate grains. Refractories 1978, 19 (1-2), 40-44.
7. Dunn, B.; Zink, J. I., Sol-gel chemistry and materials. Acc Chem Res 2007, 40 (9), 729.
8. Pfaff, G., Synthesis of calcium titanate powders by the sol-gel process. Chemistry of Materials 1994, 6 (1), 58-62.
9. DeVries, R. C.; Roy, R., Phase Equilibria in the System BaTiO3-CaTiO3. Journal of the American Ceramic Society 1955, 38 (4), 142-146.
10. Moon, J.; Li, T.; Randall, C. A.; Adair, J. H., Low temperature synthesis of lead titanate by a hydrothermal method. Journal of Materials Research 1997, 12 (1), 189-197.
11. Pfaff, G.; Schmidt, F.; Ludwig, W.; Feltz, A., MIITiO(C2O4)2·4H2O (MII=Mg, Ca, Sr OR Ba) as precursors in the formation of MIITiO3 powders. Journal of Thermal Analysis 1988, 33 (3), 771-779.
12. Beskow, G., V. M. Goldschmidt: Geochemische Verteilungsgesetze der Elemente. Geologiska Föreningen i Stockholm Förhandlingar 1924, 46 (6-7), 738-743.
13. Xiao, J.-W.; Liu, L.; Zhang, D.; De Marco, N.; Lee, J.-W.; Lin, O.; Chen, Q.; Yang, Y., The Emergence of the Mixed Perovskites and Their Applications as Solar Cells. Advanced Energy Materials 2017, 7 (20), 1700491.
14. Opel, M., Spintronic oxides grown by laser-MBE. Journal of Physics D: Applied Physics 2012, 45 (3), 033001.
15. Bokdam, M.; Sander, T.; Stroppa, A.; Picozzi, S.; Sarma, D. D.; Franchini, C.; Kresse, G., Role of Polar Phonons in the Photo Excited State of Metal Halide Perovskites. Sci Rep 2016, 6, 28618.
16. Yin, W.-J.; Shi, T.; Yan, Y., Superior Photovoltaic Properties of Lead Halide Perovskites: Insights from First-Principles Theory. The Journal of Physical Chemistry C 2015, 119 (10), 5253-5264.
17. Ponseca, C. S., Jr.; Savenije, T. J.; Abdellah, M.; Zheng, K.; Yartsev, A.; Pascher, T.; Harlang, T.; Chabera, P.; Pullerits, T.; Stepanov, A.; Wolf, J. P.; Sundstrom, V., Organometal halide perovskite solar cell materials rationalized: ultrafast charge generation, high and microsecond-long balanced mobilities, and slow recombination. J Am Chem Soc 2014, 136 (14), 5189-5192.
18. Xing, G.; Mathews, N.; Sun, S.; Lim, S. S.; Lam, Y. M.; Gratzel, M.; Mhaisalkar, S.; Sum, T. C., Long-range balanced electron- and hole-transport lengths in organic-inorganic CH3NH3PbI3. Science 2013, 342 (6156), 344-347.
19. Hong, K.; Le, Q. V.; Kim, S. Y.; Jang, H. W., Low-dimensional halide perovskites: review and issues. Journal of Materials Chemistry C 2018, 6 (9), 2189-2209.
20. Eperon, G. E.; Stranks, S. D.; Menelaou, C.; Johnston, M. B.; Herz, L. M.; Snaith, H. J., Formamidinium lead trihalide: a broadly tunable perovskite for efficient planar heterojunction solar cells. Energy & Environmental Science 2014, 7 (3), 982-988.
21. Chen, L.; Tan, Y. Y.; Chen, Z. X.; Wang, T.; Hu, S.; Nan, Z. A.; Xie, L. Q.; Hui, Y.; Huang, J. X.; Zhan, C.; Wang, S. H.; Zhou, J. Z.; Yan, J. W.; Mao, B. W.; Tian, Z. Q., Toward Long-Term Stability: Single-Crystal Alloys of Cesium-Containing Mixed Cation and Mixed Halide Perovskite. J Am Chem Soc 2019, 141 (4), 1665-1671.
22. Ogomi, Y.; Morita, A.; Tsukamoto, S.; Saitho, T.; Fujikawa, N.; Shen, Q.; Toyoda, T.; Yoshino, K.; Pandey, S. S.; Ma, T.; Hayase, S., CH3NH3SnxPb(1-x)I3 Perovskite Solar Cells Covering up to 1060 nm. J Phys Chem Lett 2014, 5 (6), 1004-1011.
23. Noh, J. H.; Im, S. H.; Heo, J. H.; Mandal, T. N.; Seok, S. I., Chemical management for colorful, efficient, and stable inorganic-organic hybrid nanostructured solar cells. Nano Lett 2013, 13 (4), 1764-1769.
24. Liang, X.; Baker, R. W.; Wu, K.; Deng, W.; Ferdani, D.; Kubiak, P. S.; Marken, F.; Torrente-Murciano, L.; Cameron, P. J., Continuous low temperature synthesis of MAPbX3 perovskite nanocrystals in a flow reactor. Reaction Chemistry & Engineering 2018, 3 (5), 640-644.
25. Lim, E. L.; Yap, C. C.; Jumali, M. H. H.; Teridi, M. A. M.; Teh, C. H., A Mini Review: Can Graphene Be a Novel Material for Perovskite Solar Cell Applications? Nanomicro Lett 2018, 10 (2), 27.
26. Cheng, Z.; Lin, J., Layered organic–inorganic hybrid perovskites: structure, optical properties, film preparation, patterning and templating engineering. CrystEngComm 2010, 12 (10), 2646-2662.
27. Stoumpos, C. C.; Cao, D. H.; Clark, D. J.; Young, J.; Rondinelli, J. M.; Jang, J. I.; Hupp, J. T.; Kanatzidis, M. G., Ruddlesden–Popper Hybrid Lead Iodide Perovskite 2D Homologous Semiconductors. Chemistry of Materials 2016, 28 (8), 2852-2867.
28. Pradeesh, K.; Baumberg, J. J.; Prakash, G. V., Strong exciton-photon coupling in inorganic-organic multiple quantum wells embedded low-Q microcavity. Opt Express 2009, 17 (24), 22171-22178.
29. Qian, J.; Guo, Q.; Liu, L.; Xu, B.; Tian, W., A theoretical study of hybrid lead iodide perovskite homologous semiconductors with 0D, 1D, 2D and 3D structures. Journal of Materials Chemistry A 2017, 5 (32), 16786-16795.
30. Chen, Y.; Sun, Y.; Peng, J.; Tang, J.; Zheng, K.; Liang, Z., 2D Ruddlesden-Popper Perovskites for Optoelectronics. Adv Mater 2018, 30 (2), 1703487.
31. Ruddlesden, S. N.; Popper, P., New compounds of the K2NIF4type. Acta Crystallographica 1957, 10 (8), 538-539.
32. Ruddlesden, S. N.; Popper, P., The compound Sr3Ti2O7and its structure. Acta Crystallographica 1958, 11 (1), 54-55.
33. Calabrese, J.; Jones, N. L.; Harlow, R. L.; Herron, N.; Thorn, D. L.; Wang, Y., Preparation and characterization of layered lead halide compounds. Journal of the American Chemical Society 1991, 113 (6), 2328-2330.
34. Smith, I. C.; Hoke, E. T.; Solis-Ibarra, D.; McGehee, M. D.; Karunadasa, H. I., A layered hybrid perovskite solar-cell absorber with enhanced moisture stability. Angew Chem Int Ed Engl 2014, 126 (42), 11414-11417.
35. Hong, X.; Ishihara, T.; Nurmikko, A. V., Dielectric confinement effect on excitons in PbI4-based layered semiconductors. Phys Rev B Condens Matter 1992, 45 (12), 6961-6964.
36. Peng, W.; Yin, J.; Ho, K. T.; Ouellette, O.; De Bastiani, M.; Murali, B.; El Tall, O.; Shen, C.; Miao, X.; Pan, J.; Alarousu, E.; He, J. H.; Ooi, B. S.; Mohammed, O. F.; Sargent, E.; Bakr, O. M., Ultralow Self-Doping in Two-dimensional Hybrid Perovskite Single Crystals. Nano Lett 2017, 17 (8), 4759-4767.
37. Yuan, M.; Quan, L. N.; Comin, R.; Walters, G.; Sabatini, R.; Voznyy, O.; Hoogland, S.; Zhao, Y.; Beauregard, E. M.; Kanjanaboos, P.; Lu, Z.; Kim, D. H.; Sargent, E. H., Perovskite energy funnels for efficient light-emitting diodes. Nat Nanotechnol 2016, 11 (10), 872-877.
38. Liang, D.; Peng, Y.; Fu, Y.; Shearer, M. J.; Zhang, J.; Zhai, J.; Zhang, Y.; Hamers, R. J.; Andrew, T. L.; Jin, S., Color-Pure Violet-Light-Emitting Diodes Based on Layered Lead Halide Perovskite Nanoplates. ACS Nano 2016, 10 (7), 6897-6904.
39. Tsai, H.; Nie, W.; Blancon, J. C.; Stoumpos, C. C.; Asadpour, R.; Harutyunyan, B.; Neukirch, A. J.; Verduzco, R.; Crochet, J. J.; Tretiak, S.; Pedesseau, L.; Even, J.; Alam, M. A.; Gupta, G.; Lou, J.; Ajayan, P. M.; Bedzyk, M. J.; Kanatzidis, M. G., High-efficiency two-dimensional Ruddlesden-Popper perovskite solar cells. Nature 2016, 536 (7616), 312-316.
40. Huang, J.; Shao, Y.; Dong, Q., Organometal Trihalide Perovskite Single Crystals: A Next Wave of Materials for 25% Efficiency Photovoltaics and Applications Beyond? The Journal of Physical Chemistry Letters 2015, 6 (16), 3218-3227.
41. Poglitsch, A.; Weber, D., Dynamic disorder in methylammoniumtrihalogenoplumbates (II) observed by millimeter‐wave spectroscopy. The Journal of Chemical Physics 1987, 87 (11), 6373-6378.
42. Dang, Y.; Liu, Y.; Sun, Y.; Yuan, D.; Liu, X.; Lu, W.; Liu, G.; Xia, H.; Tao, X., Bulk crystal growth of hybrid perovskite material CH3NH3PbI3. CrystEngComm 2015, 17 (3), 665-670.
43. Dong, Q.; Fang, Y.; Shao, Y.; Mulligan, P.; Qiu, J.; Cao, L.; Huang, J., Solar cells. Electron-hole diffusion lengths > 175 µm in solution-grown CH3NH3PbI3 single crystals. Science 2015, 347 (6225), 967-970.
44. Shi, D.; Adinolfi, V.; Comin, R.; Yuan, M.; Alarousu, E.; Buin, A.; Chen, Y.; Hoogland, S.; Rothenberger, A.; Katsiev, K.; Losovyj, Y.; Zhang, X.; Dowben, P. A.; Mohammed, O. F.; Sargent, E. H.; Bakr, O. M., Solar cells. Low trap-state density and long carrier diffusion in organolead trihalide perovskite single crystals. Science 2015, 347 (6221), 519-522.
45. Saidaminov, M. I.; Abdelhady, A. L.; Murali, B.; Alarousu, E.; Burlakov, V. M.; Peng, W.; Dursun, I.; Wang, L.; He, Y.; Maculan, G.; Goriely, A.; Wu, T.; Mohammed, O. F.; Bakr, O. M., High-quality bulk hybrid perovskite single crystals within minutes by inverse temperature crystallization. Nature Communications 2015, 6, 7586.
46. Yang, S.; Niu, W.; Wang, A. L.; Fan, Z.; Chen, B.; Tan, C.; Lu, Q.; Zhang, H., Ultrathin Two-Dimensional Organic-Inorganic Hybrid Perovskite Nanosheets with Bright, Tunable Photoluminescence and High Stability. Angew Chem Int Ed Engl 2017, 56 (15), 4252-4255.
47. Raghavan, C. M.; Chen, T. P.; Li, S. S.; Chen, W. L.; Lo, C. Y.; Liao, Y. M.; Haider, G.; Lin, C. C.; Chen, C. C.; Sankar, R.; Chang, Y. M.; Chou, F. C.; Chen, C. W., Low-Threshold Lasing from 2D Homologous Organic-Inorganic Hybrid Ruddlesden-Popper Perovskite Single Crystals. Nano Lett 2018, 18 (5), 3221-3228.
48. Zhang, X.; Xu, B.; Zhang, J.; Gao, Y.; Zheng, Y.; Wang, K.; Sun, X. W., All-Inorganic Perovskite Nanocrystals for High-Efficiency Light Emitting Diodes: Dual-Phase CsPbBr3-CsPb2Br5 Composites. Advanced Functional Materials 2016, 26 (25), 4595-4600.
49. Song, J.; Li, J.; Li, X.; Xu, L.; Dong, Y.; Zeng, H., Quantum Dot Light-Emitting Diodes Based on Inorganic Perovskite Cesium Lead Halides (CsPbX3 ). Adv Mater 2015, 27 (44), 7162-7167.
50. Byun, J.; Cho, H.; Wolf, C.; Jang, M.; Sadhanala, A.; Friend, R. H.; Yang, H.; Lee, T. W., Efficient Visible Quasi-2D Perovskite Light-Emitting Diodes. Adv Mater 2016, 28 (34), 7515-7520.
51. Kim, Y. H.; Cho, H.; Heo, J. H.; Kim, T. S.; Myoung, N.; Lee, C. L.; Im, S. H.; Lee, T. W., Multicolored organic/inorganic hybrid perovskite light-emitting diodes. Adv Mater 2015, 27 (7), 1248-1254.
52. Huang, H.; Zhao, F.; Liu, L.; Zhang, F.; Wu, X. G.; Shi, L.; Zou, B.; Pei, Q.; Zhong, H., Emulsion Synthesis of Size-Tunable CH3NH3PbBr3 Quantum Dots: An Alternative Route toward Efficient Light-Emitting Diodes. ACS Appl Mater Interfaces 2015, 7 (51), 28128-28133.
53. Xiao, Z.; Kerner, R. A.; Zhao, L.; Tran, N. L.; Lee, K. M.; Koh, T.-W.; Scholes, G. D.; Rand, B. P., Efficient perovskite light-emitting diodes featuring nanometre-sized crystallites. Nature Photonics 2017, 11, 108-115.
54. Ahmadi, M.; Wu, T.; Hu, B., A Review on Organic-Inorganic Halide Perovskite Photodetectors: Device Engineering and Fundamental Physics. Adv Mater 2017, 29 (41), 1605242.
55. Li, D.; Dong, G.; Li, W.; Wang, L., High performance organic-inorganic perovskite-optocoupler based on low-voltage and fast response perovskite compound photodetector. Sci Rep 2015, 5, 7902.
56. Dou, L.; Yang, Y. M.; You, J.; Hong, Z.; Chang, W. H.; Li, G.; Yang, Y., Solution-processed hybrid perovskite photodetectors with high detectivity. Nat Commun 2014, 5, 5404.