Molecular Origin of the Asymmetric Photoluminescence Spectra of CsPbBr3 at Low Temperature.
J Phys Chem Lett
; 12(10): 2699-2704, 2021 Mar 18.
Article
em En
| MEDLINE
| ID: mdl-33703902
ABSTRACT
CsPbBr3 has received wide attention due to its superior emission yield and better thermal stability compared to other organic-inorganic lead halide perovskites. In this study, through an interplay of theory and experiments, we investigate the molecular origin of the asymmetric low-temperature photoluminescence spectra of CsPbBr3. We conclude that the origin of this phenomenon lies in a local dipole moment (and the induced Stark effect) due to the preferential localization of Cs+ in either of two off-center positions of the empty space between the surrounding PbBr6 octahedra. With increasing temperature, Cs+ ions are gradually occupying positions closer and closer to the center of the cavities. The gradual loss of ordering in the Cs+ position with increasing temperature is the driving force for the formation of tetragonal-like arrangements within the orthorhombic lattice.
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MEDLINE
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En
Ano de publicação:
2021
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Article