Top and bottom surfaces limit carrier lifetime in lead iodide perovskite films

Ye Yang, Mengjin Yang, David T. Moore, Yong Yan, Elisa M. Miller, Kai Zhu, Matthew C. Beard

Research output: Contribution to journalArticlepeer-review

188 Scopus citations

Abstract

Carrier recombination at defects is detrimental to the performance of solar energy conversion systems, including solar cells and photoelectrochemical devices. Point defects are localized within the bulk crystal while extended defects occur at surfaces and grain boundaries. If not properly managed, surfaces can be a large source of carrier recombination. Separating surface carrier dynamics from bulk and/or grain-boundary recombination in thin films is challenging. Here, we employ transient reflection spectroscopy to measure the surface carrier dynamics in methylammonium lead iodide perovskite polycrystalline films. We find that surface recombination limits the total carrier lifetime in perovskite polycrystalline thin films, meaning that recombination inside grains and/or at grain boundaries is less important than top and bottom surface recombination. The surface recombination velocity in polycrystalline films is nearly an order of magnitude smaller than that in single crystals, possibly due to unintended surface passivation of the films during synthesis.

Original languageEnglish (US)
Article number16207
JournalNature Energy
Volume2
Issue number2
DOIs
StatePublished - Jan 13 2017

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Renewable Energy, Sustainability and the Environment
  • Fuel Technology
  • Energy Engineering and Power Technology

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