Tunable Optical Properties and Charge Separation in CH3NH3SnxPb1-xI3/TiO2-Based Planar Perovskites Cells

Hong Jian Feng, Tula R. Paudel, Evgeny Y. Tsymbal, Xiao Cheng Zeng

Research output: Contribution to journalArticle

88 Scopus citations

Abstract

A sharp potential drop across the interface of the Pb-rich halide perovskites/TiO2 heterostructure is predicted from first-principles calculations, suggesting enhanced separation of photoinduced charge carriers in the perovskite-based photovoltaic solar cells. The potential drop appears to be associated with the charge accumulation at the polar interface. More importantly, on account of both the β phase structure of CH3NH3SnxPb1-xI3 for x < 0.5 and the α phase structure of CH3NH3SnxPb1-xI3 for x ≥ 0.5, the computed optical absorption spectra from time-dependent density functional theory (TD-DFT) are in very good agreement with the measured spectra from previous experiments. Our TD-DFT computation also confirms the experimental structures of the mixed Pb-Sn organometal halide perovskites. These computation results provide a highly sought answer to the question why the lead-based halide perovskites possess much higher power conversion efficiencies than the tin-based counterparts for solar-cell applications. (Chemical Equation Presented).

Original languageEnglish (US)
Pages (from-to)8227-8236
Number of pages10
JournalJournal of the American Chemical Society
Volume137
Issue number25
DOIs
StatePublished - Jul 1 2015

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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