Pressure-Dependent Polymorphism and Band-Gap Tuning of Methylammonium Lead Iodide Perovskite

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• 作者：Shaojie Jiang ; Dr. Yanan Fang ; Dr. Ruipeng Li ; Dr. Hai Xiao ; Jason Crowley ; Dr. Chenyu Wang ; Prof. Timothy J. White ; Prof. William A. Goddard III ; Dr. Zhongwu Wang ; Dr. Tom Baikie and Prof. Jiye Fang
• 刊名：Angewandte Chemie
• 出版年：2016
• 出版时间：May 23, 2016
• 年：2016
• 卷：128
• 期：22
• 页码：6650-6654
• 全文大小：1687K
• ISSN：1521-3757

文摘

We report the pressure-induced crystallographic transitions and optical behavior of MAPbI₃ (MA=methylammonium) using in situ synchrotron X-ray diffraction and laser-excited photoluminescence spectroscopy, supported by density functional theory (DFT) calculations using the hybrid functional B3PW91 with spin-orbit coupling. The tetragonal polymorph determined at ambient pressure transforms to a ReO₃-type cubic phase at 0.3 GPa. Upon continuous compression to 2.7 GPa this cubic polymorph converts into a putative orthorhombic structure. Beyond 4.7 GPa it separates into crystalline and amorphous fractions. During decompression, this phase-mixed material undergoes distinct restoration pathways depending on the peak pressure. In situ pressure photoluminescence investigation suggests a reduction in band gap with increasing pressure up to ≈0.3 GPa and then an increase in band gap up to a pressure of 2.7 GPa, in excellent agreement with our DFT calculation prediction.