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Putting the Squeeze on Lead Iodide Perovskites: Pressure-Induced Effects to Tune Their Structural and Optoelectronic Behavior

Lookup NU author(s): Dr James DawsonORCiD



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


© 2019 American Chemical Society.Lattice compression through hydrostatic pressure has emerged as an effective means of tuning the structural and optoelectronic properties of hybrid halide perovskites. In addition to external pressure, the local strain present in solution-processed thin films also causes significant heterogeneity in their photophysical properties. However, an atomistic understanding of structural changes of hybrid perovskites under pressure and their effects on the electronic landscape is required. Here, we use high level ab initio simulation techniques to explore the effect of lattice compression on the formamidinium (FA) lead iodide compound, FA1-xCsxPbI3 (x = 0, 0.25). We show that, in response to applied pressure, the Pb-I bonds shorten, the PbI6 octahedra tilt anisotropically, and the rotational dynamics of the FA+ molecular cation are partially suppressed. Because of these structural distortions, the compressed perovskites exhibit band gaps that are narrower (red-shifted) and indirect with spin-split band edges. Furthermore, the shallow defect levels of intrinsic iodide defects transform to deep-level states with lattice compression. This work highlights the use of hydrostatic pressure as a powerful tool for systematically modifying the photovoltaic performance of halide perovskites.

Publication metadata

Author(s): Ghosh D, Aziz A, Dawson JA, Walker AB, Islam MS

Publication type: Article

Publication status: Published

Journal: Chemistry of Materials

Year: 2019

Volume: 31

Issue: 11

Pages: 4063-4071

Print publication date: 11/06/2019

Online publication date: 14/05/2019

Acceptance date: 02/04/2019

Date deposited: 15/01/2020

ISSN (print): 0897-4756

ISSN (electronic): 1520-5002

Publisher: American Chemical Society


DOI: 10.1021/acs.chemmater.9b00648


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