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Photo-induced Dual Passivation via Usanovich Acid-Base on Surface Defects of Methylammonium Lead Triiodide Perovskite

Abstract

Post-fabrication defect passivation of organometal halide perovskites has become an efficient way to improve their photophysical properties, but the underlying mechanisms are still in debate. In this work, we used p-benzoquinone (p-BQ) to generate surface defects on methylammonium lead triiodide perovskite (MAPbI3), and found that a Usanovich acid-base (O2, acetone or acetonitrile) treatment can effectively passivate those defects and lead to photoluminescence (PL) enhancement. The passivation effect arose from partial neutralization of defect charges via electron transfer between passivation reagents and relevant defects. O2 accepted photo-generated electrons, formed negatively charged oxygen species and attached to the I vacancy site to reduce its PL quenching efficiency by neutralising defect's positive charge. Likewise, acetone accepted photo-generated holes, formed positively charged species and partially neutralised defect's negative charge. The reduced trapping ability of defects caused the PL enhancement. In addition, observed photo-catalysed oxidization of acetone by O2 on crystal surface supported the single electron transfer mechanism, and showed potential of MAPbI3 as photo-catalyst.

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Publication details

The article was accepted on 08 Oct 2018 and first published on 09 Oct 2018


Article type: Paper
DOI: 10.1039/C8CP06112B
Citation: Phys. Chem. Chem. Phys., 2018, Accepted Manuscript
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    Photo-induced Dual Passivation via Usanovich Acid-Base on Surface Defects of Methylammonium Lead Triiodide Perovskite

    Y. Yu, S. Wan, D. Hong and Y. Tian, Phys. Chem. Chem. Phys., 2018, Accepted Manuscript , DOI: 10.1039/C8CP06112B

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