Pressure-Induced Phase Transformation, Reversible Amorphization, and Anomalous Visible Light Response in Organolead Bromide Perovskite.
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 Pm3̅m to Im3̅, 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.
High Pressure Science and Engineering Center, University of Nevada , Las Vegas, Nevada 89154, United States.|High Pressure Synergetic Consortium (HPSynC), Geophysical Laboratory, Carnegie Institution of Washington , Argonne, Illinois 60439, United States.|Institute of Nanostructured Functional Materials, Huanghe Science and Technology College , Zhengzhou, Henan 450006, China.
Yonggang
Y
Wang
High Pressure Science and Engineering Center, University of Nevada , Las Vegas, Nevada 89154, United States.
Xujie
X
Lü
High Pressure Synergetic Consortium (HPSynC), Geophysical Laboratory, Carnegie Institution of Washington , Argonne, Illinois 60439, United States.|Center for High Pressure Science and Technology Advanced Research (HPSTAR) , Shanghai 201203, China.
Wenge
W
Yang
Institute of Nanostructured Functional Materials, Huanghe Science and Technology College , Zhengzhou, Henan 450006, China.
Ting
T
Wen
High Pressure Synergetic Consortium (HPSynC), Geophysical Laboratory, Carnegie Institution of Washington , Argonne, Illinois 60439, United States.
Liuxiang
L
Yang
Center for High Pressure Science and Technology Advanced Research (HPSTAR) , Shanghai 201203, China.
Xiangting
X
Ren
High Pressure Synergetic Consortium (HPSynC), Geophysical Laboratory, Carnegie Institution of Washington , Argonne, Illinois 60439, United States.|Center for High Pressure Science and Technology Advanced Research (HPSTAR) , Shanghai 201203, China.
Lin
L
Wang
Centre for Crystal Research and Development, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences , Beijing 100190, China.
Zheshuai
Z
Lin
High Pressure Science and Engineering Center, University of Nevada , Las Vegas, Nevada 89154, United States.
Yusheng
Y
Zhao