Pressure-Dependent Polymorphism and Band-Gap Tuning of Methylammonium Lead Iodide Perovskite.
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.
Materials Science and Engineering Program, State University of New York at Binghamton, Binghamton, NY, 13902, USA.
Shaojie
S
Jiang
Energy Research Institute@NTU (ERI@N), Nanyang Technological University, 50 Nanyang Drive, Singapore, 637553, Republic of Singapore.
Yanan
Y
Fang
Cornell High Energy Synchrotron Source, Cornell University, Ithaca, NY, 14853, USA.
Ruipeng
R
Li
Materials and Process Simulation Center (MSC) and Joint Center for Artificial Photosynthesis (JCAP), California Institute of Technology, Pasadena, CA, 91125, USA.
Hai
H
Xiao
Materials and Process Simulation Center (MSC) and Joint Center for Artificial Photosynthesis (JCAP), California Institute of Technology, Pasadena, CA, 91125, USA.
Jason
J
Crowley
Department of Chemistry, State University of New York at Binghamton, Binghamton, NY, 13902, USA.
Chenyu
C
Wang
School of Materials Science and Engineering, Nanyang Technological University, Nanyang Avenue, Singapore, 639798, Republic of Singapore.
Timothy J
TJ
White
Materials and Process Simulation Center (MSC) and Joint Center for Artificial Photosynthesis (JCAP), California Institute of Technology, Pasadena, CA, 91125, USA. wag@wag.caltech.edu.
William A
WA
Goddard
Cornell High Energy Synchrotron Source, Cornell University, Ithaca, NY, 14853, USA.
Zhongwu
Z
Wang
Energy Research Institute@NTU (ERI@N), Nanyang Technological University, 50 Nanyang Drive, Singapore, 637553, Republic of Singapore. tbaikie@ntu.edu.sg.
Tom
T
Baikie
Materials Science and Engineering Program, State University of New York at Binghamton, Binghamton, NY, 13902, USA. jfang@binghamton.edu.|Department of Chemistry, State University of New York at Binghamton, Binghamton, NY, 13902, USA. jfang@binghamton.edu.
Jiye
J
Fang
band gap; halide perovskite; high-pressure chemistry; phase transitions; photoluminescence