Spectral dependence of direct and trap-mediated recombination processes in lead halide perovskites using time resolved microwave conductivity

Joanna A. Guse, Arman M. Soufiani, Liangcong Jiang, Jincheol Kim, Yi-Bing Cheng, Timothy W. Schmidt, Anita Ho-Baillie, Dane R. McCamey*

*Corresponding author for this work

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

Elucidating the decay mechanisms of photoexcited charge carriers is key to improving the efficiency of solar cells based on organo-lead halide perovskites. Here we investigate the spectral dependence (via above-, inter- and sub-bandgap optical excitations) of direct and trap-mediated decay processes in CH3NH3PbI3 using time resolved microwave conductivity (TRMC). We find that the total end-of-pulse mobility is excitation wavelength dependent-the mobility is maximized (172 cm2 V-1 s-1) when charge carriers are excited by near bandgap light (780 nm) in the low charge carrier density regime (109 photons per cm2), and is lower for above- and sub-bandgap excitations. Direct recombination is found to occur on the 100-400 ns timescale across excitation wavelengths near and above the bandgap, whereas indirect recombination processes displayed distinct behaviour following above- and sub-bandgap excitations, suggesting the influence of different trap distributions on recombination dynamics.

Original languageEnglish
Pages (from-to)12043-12049
Number of pages7
JournalPhysical Chemistry Chemical Physics
Volume18
Issue number17
DOIs
Publication statusPublished - 7 May 2016
Externally publishedYes

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