Top and Bottom Surfaces Limit Carrier Lifetime in Lead Iodide Perovskite Films

Matthew Beard, Mengjin Yang, David Moore, Elisa Link, Kai Zhu, Ye Yang, Yong Yan

Research output: Contribution to journalArticlepeer-review

370 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 languageAmerican English
Article number16207
Number of pages7
JournalNature Energy
Volume2
Issue number2
DOIs
StatePublished - 13 Jan 2017

Bibliographical note

Publisher Copyright:
© 2017 Macmillan Publishers Limited, part of Springer Nature. All rights reserved.

NREL Publication Number

  • NREL/JA-5900-67004

Keywords

  • perovskite solar cells
  • solar-photochemistry
  • surface recombination
  • transient spectroscopy

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