混合鈣鈦礦材料的生長與特徵

最近，鈣鈦礦太陽能電池的效率在短間內攀高，受到大家廣泛的關注。有機 - 無機滷化物鈣鈦礦材料可以製備成薄膜或單晶。鈣鈦礦單晶非常適合研究其基本物理特性，因為單晶材料因為沒有晶界而具有低的缺陷密度。然而，在研究鈣鈦礦單晶如MAPbI3和FAPbI3時，這些材料仍然具有一些關鍵問題，即MAPbI3在85 ℃以上不穩定，而FAPbI3（立方相，α-FAPbI3）在室溫下熱力學不穩定，其將自發地轉變成具有低遷移率和電導率的非鈣鈦礦結構（六方相，δ-FAPbI3）。無機Cs陽離子對有機MA陽離子而言較為穩定，並且其離子半徑小於MA和FA。本研究即擬定觀察到三重陽離子(即Cs、FA和MA) 的生長和特性。通過使用ITC方法將這些化合物混合為Csx（FA0.83MA0.17）（1-x）PbI3，其中x = 0, 0.05和0.1。結果表明，不同濃度銫的鈣鈦礦Csx（FA0.83MA0.17）（1-x）PbI3具有不錯的穩定性，在未來可望繼續發展。本研究發現此材料的主要衍射峰與MAPbI3相似，並且通過計算表明能帶隙Csx（FA0.83MA0.17）（1-x）PbI3單晶為1.46, 1.49和1.52 eV。這些結果接近材料的能帶。

關鍵字

钙钛矿单晶； Csx（FA0.83MA0.17）（1-x）PbI3 ；能带隙；稳定性

並列摘要

Today, Perovskite solar cells (PSCs) have a emerging technology that has been successful to reach high efficiency in relatively short time. Generally, there are two type of organic-inorganic hybrid halide perovskites i.e., thin film and single crystals. Perovskite single crystals are highly suitable to observe properties material detailly due to their low trap density and no grain boundaries so that it has a low defect. However, during study of perovskite single crystals such as MAPbI3 and FAPbI3 show that growth single crystal with those materials still have some critical issue which for MAPbI3 is inherently thermally unstable at temperatures over 85 0C, while FAPbI3 (cubic phase, α-FAPbI3) is thermodynamic unstable at room temperature (RT), which will spontaneously convert to a non-perovskite structure (hexagonal phase, δ-FAPbI3) with low mobility and conductivity. inorganic Cs cation is much less volatile with organic MA cation and it has an ionic radius smaller than MA and FA. This experiment observed the growth and characterization of triple cation which are Cs, FA, and MA. These compounds are mixed be Csx(FA0.83MA0.17)(1-x)PbI3 with x= 0, 0.05, and 0.10 by using ITC method. From the result shows that perovskite Csx(FA0.83MA0.17)(1-x)PbI3 with different concentration of cesium gives a promising to develop in near the future. It is found that the main diffraction peaks of this material are similar with MAPbI3 and also from calculation shows that the energy band gaps Csx(FA0.83MA0.17)(1-x)PbI3 single crystal are 1.46, 1.49, and 1.52 eV which these results approach to theoretical of band gap of perovskite solar cells.