Pressure-Induced Structural Evolution and Optical Properties of Metal-Halide Perovskite CsPbCl₃

Abstract

Metal-halide perovskites have emerged as the most promising semiconductor materials for advanced photovoltaic and optoelectronic applications. Herein, we comprehensively investigate the optical response and structural evolution of metal-halide perovskite CsPbCl3 (ABX3) upon compression. Band gap realized a pronounced narrowing under mild pressure followed by a sharp increase, which could be ascribed to Pb–Cl bond contraction and inorganic framework distortion, respectively. The transformation of the crystal structure is confirmed and analyzed through in situ high-pressure X-ray diffraction and Raman experiments, consistent with the evolution of optical properties. Combining with the first-principles calculations, we understand the electronic band structure changes and phase transition mechanism, which are ascribed to severe PbCl6 octahedral titling and twisting. Our results demonstrate that the high-pressure technique can be used as a practical tool to modify the optical properties of metal-halide perovskites and maps an innovative strategy for better photovoltaic and optoelectronic device design.

Polymorphism in metal halide perovskites

“…These trends are exemplified in a recent comparison of the temperature-dependent optical bandgaps of CsPbBr 3 , MAPbBr 3 , and FAPbBr 3 single crystals. 184 As observed from Figure 12, optical bandgaps decrease with increasing tolerance [162][163][164][165][166][167][168][169][170] The white section in the data for MAPbBr 3 indicates a region where data was not available. 15,185,186 Overall, the bandgaps of halide perovskites are strongly correlated to the M-X-M bond angle, 187,188 which can range from 150 -180 o , as described in detail in a 2015 account by Stoumpos and Kanatzidis.…”

“…These trends are exemplified in a recent comparison of the temperature-dependent optical bandgaps of CsPbBr 3 , MAPbBr 3 , and FAPbBr 3 single crystals. 184 As observed from Figure 12, optical bandgaps decrease with increasing tolerance [162][163][164][165][166][167][168][169][170] The white section in the data for MAPbBr 3 indicates a region where data was not available. Please do not adjust margins Please do not adjust margins factors of 0.92, 1.04, and 1.14 for CsPbBr 3 , MAPbBr 3 , and FaPbBr 3 , respectively.…”

Structural, Thermodynamical and Electronic Properties of All-Inorganic Lead Halide Perovskites

“…The phase transitions of CsPbI3 from high temperature to room temperature at ambient conditions are going through cubic to tetragonal phase at 260 °C, tetragonal to orthorhombic phase at 175 °C and then orthorhombic phase transition to non-perovskite δ-phase after standing a few days later 37 . Concerning the cubic phase, the phase transitions are accompanied by lead-halide octahedral tilting and distortion 38 , which affect the stability, electronic and photophysical properties 39 . In addition, the halogen anions also affect the electronic properties of lead halide perovskite 40 .…”

Pressure-Induced Void and Crack Closure Improves the Photoconversion Efficiency and Stability of Perovskite Solar Cells

“…The use of pressure has been shown to improve optoelectronic properties of perovskite lms [18][19][20][21] . In particular, the application of moderate pressure, during the fabrication of PSCs, has also been shown to improve interfacial surface contacts in multilayered structures of mixed-halide methylammonium perovskite solar cells, leading to enhanced e ciencies 22 .…”