以鉛鹵化物鈣鈦礦做為主動層之鈣鈦礦太陽能電池(Perovskite solar cell, PSC) ，因其高的光電轉換效率獲得大家高度的重視。若能合成出具有高純度之鈣鈦礦單晶，可幫助我們了解此材料之物理性質。本研究使用可快速長晶的逆溫度結晶法，搭配不同溶劑及不同比例的陽離子或鹵素混合，製備出含混合鹵素或混合陽離子之鈣鈦礦單晶。結果顯示，所長之單晶與其起始溶液中之溶質的組成不同。在含有I-/Br-之系統中，起始溶質組成為MABr : PbI2 = 1 : 1時，所長成之晶體組成為MAPbI0.78Br2.22，單晶中所含之Br比例高於起始物，可能是Br-與MA+可形成較穩定的晶格。在含有Br-/Cl-之系統中，起始溶質組成為MABr : PbCl2 = 1 : 1時，所成長之晶體組成為MAPbCl2.77Br0.23。而在起始溶質為MACl : PbBr2 = 1 : 1時，所得晶體組成則為MAPbCl1.35Br1.65，晶體中Cl-之比例皆較其起始溶質之比例高，推測因溶解度較小之氯化物在長晶過程中較快沉澱出來。在含Cs+與MA+或FA+之混摻陽離子系統中，以0.24 M CsI + 0.65 M MAI + 0.89 M PbBr2或是0.22 M CsI + 0.71 M FAI + 0.93 M PbBr2為起始物時，所長出之晶體經EDS測量得到之組成分別為CsPbI0.05Br2.95以及CsPbI0.15Br2.85，因Cs+與Br-離子半徑之比率有利於形成純Cs陽離子之鈣鈦礦結構。;Perovskite solar cell (PSC) based on lead halide perovskite has attract highly attention due to its high power conversion efficiency. Being able to prepare perovskite single crystal with high purity will help us to understand the physical properties of these materials. In this study, we use inverse temperature crystallization method to grow perovskite single crystal with various stoichiometries by using different solvents, various cations and halides. It was found that the compositions of the crystals and the solutes in the precursor solution are different. The composition of crystal grown from 1.3 M MABr + 1.3 M PbI2/DMF : GBL = 2 : 1 solution is MAPbI0.78Br2.22, the bromide ratio in crystal is higher than that in solute, indicating that bromide ion is more suitable to form bromide perovskite structure. Crystal grown from 1.0 M MABr + 1.0 M PbCl2/DMF : DMSO = 2 : 1 is MAPbCl2.77Br0.23, from 0.8 M MACl + 0.8 M PbBr2 /DMF : DMSO = 9 : 1 is MAPbCl1.35Br1.65. Both results show that the chloride content in the crystal is higher than that in the solute, probably due to Cl- ion containing perovskite has lower solubility. In mixed cation cases when the precursor solutions are 0.24 M CsI + 0.65 M MAI + 0.89 M PbBr2/DMF : GBL : DMSO =14 : 7 : 5 and 0.22 M CsI + 0.71 M FAI + 0.93 M PbBr2/DMF : GBL : DMSO = 8 : 12 : 8, the compositions of the resulting crystals estimated from EDS analysis are CsPbI0.05Br2.95 and CsPbI0.15Br2.85, respectively. Probably due to the radium ratio of Cs+ and Br- is proper to form perovskite structure.
