Materials Science and Engineering, National University of Singapore, 7 Engineering Drive 1, Singapore, 117574, Singapore.
Angew Chem Int Ed Engl. 2017 Dec 11;56(50):16073-16076. doi: 10.1002/anie.201710234. Epub 2017 Nov 23.
It is very important to study the crystallization of hybrid organic-inorganic perovskites because their thin films are usually prepared from solution. The investigation on the growth of perovskite films is however limited by their polycrystallinity. In this work, methylammonium lead triiodide single crystals grown from solutions with different methylammonium iodide (MAI):lead iodide (PbI ) ratios were investigated. We observed a V-shaped dependence of the crystallization onset temperature on the MAI:PbI ratio. This is attributed to the MAI effects on the supersaturation of precursors and the interfacial energy of the crystal growth. At low MAI:PbI ratio (<1.7), more MAI leads to the supersaturation of the precursors at lower temperature. At high MAI:PbI ratio, the crystal growing plans change from (100)-plane dominated to (001)-plane dominated. The latter have higher interfacial energy than the former, leading to a higher crystallization onset temperature.
研究杂化有机-无机钙钛矿的结晶非常重要，因为它们的薄膜通常是通过溶液来制备的。然而，钙钛矿薄膜的生长研究受到其多晶性的限制。在这项工作中，我们研究了不同甲脒碘（MAI）：碘化铅（PbI2）比例的溶液中生长的碘化甲基铵铅单晶体。我们观察到成核温度对 MAI：PbI2 比例的 V 形依赖性。这归因于 MAI 对前驱体过饱和度和晶体生长界面能的影响。在低 MAI：PbI2 比例（<1.7）下，更多的 MAI 导致前驱体在较低温度下过饱和度增加。在高 MAI：PbI2 比例下，晶体生长模式从（100）面为主转变为（001）面为主。后者的界面能高于前者，导致成核温度升高。
