Pressure-Induced Phase Transformation, Reversible Amorphization, and Anomalous Visible Light Response in Organolead Bromide Perovskite

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• 作者：Yonggang Wang ; Xujie L眉 ; Wenge Yang ; Ting Wen ; Liuxiang Yang ; Xiangting Ren ; Lin Wang ; Zheshuai Lin ; Yusheng Zhao
• 刊名：Journal of the American Chemical Society
• 出版年：2015
• 出版时间：September 2, 2015
• 年：2015
• 卷：137
• 期：34
• 页码：11144-11149
• 全文大小：482K
• ISSN：1520-5126

文摘

Hydrostatic pressure, as an alternative of chemical pressure to tune the crystal structure and physical properties, is a significant technique for novel function material design and fundamental research. In this article, we report the phase stability and visible light response of the organolead bromide perovskite, CH₃NH₃PbBr₃ (MAPbBr₃), under hydrostatic pressure up to 34 GPa at room temperature. Two phase transformations below 2 GPa (from Pm3虆m to Im3虆, then to Pnma) and a reversible amorphization starting from about 2 GPa were observed, which could be attributed to the tilting of PbBr₆ octahedra and destroying of long-range ordering of MA cations, respectively. The visible light response of MAPbBr₃ to pressure was studied by in situ photoluminescence, electric resistance, photocurrent measurements and first-principle simulations. The anomalous band gap evolution during compression with red-shift followed by blue-shift is explained by the competition between compression effect and pressure-induced amorphization. Along with the amorphization process accomplished around 25 GPa, the resistance increased by 5 orders of magnitude while the system still maintains its semiconductor characteristics and considerable response to the visible light irradiation. Our results not only show that hydrostatic pressure may provide an applicable tool for the organohalide perovskites based photovoltaic device functioning as switcher or controller, but also shed light on the exploration of more amorphous organometal composites as potential light absorber.