Thermodynamic Origin of the Photostability of the Two-Dimensional Perovskite PEA2Pb(I1-xBrx)4

Zehua Chen, Haibo Xue, Geert Brocks, Peter A. Bobbert (Corresponding author), Shuxia Tao (Corresponding author)

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The two-dimensional (2D) mixed halide perovskite PEA2Pb(I1-xBrx)4 exhibits high phase stability under illumination as compared to the three-dimensional (3D) counterpart MAPb(I1-xBrx)3. We explain this difference using a thermodynamic theory that considers the sum of a compositional and a photocarrier free energy. Ab initio calculations show that the improved compositional phase stability of the 2D perovskite is caused by a preferred I-Br distribution, leading to a much lower critical temperature for halide segregation in the dark than for the 3D perovskite. Moreover, a smaller increase of the band gap with Br concentration x and a markedly shorter photocarrier lifetime in the 2D perovskite reduce the driving force for phase segregation under illumination, enhancing the photostability.

Original languageEnglish
Pages (from-to)943-949
Number of pages7
JournalACS Energy Letters
Publication statusPublished - 10 Feb 2023

Bibliographical note

Funding Information:
Z.C. acknowledges funding from the Eindhoven University of Technology. H.X. acknowledges funding from the China Scholarship Council (CSC, No. 201806420038). S.T. acknowledges funding by the Computational Sciences for Energy Research (CSER) tenure track program of Shell and NWO (Project No. 15CST04-2) as well as NWO START-UP from The Netherlands. This work made use of the Dutch national e-infrastructure with the support of the SURF Cooperative (Grant No. EINF-2988).


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