Identification of lead vacancy defects in lead halide perovskites

David Keeble (Lead / Corresponding author), Julia Wiktor, Sandeep K. Pathak, Laurie J. Phillips, Marcel Dickmann, Ken Durose, Henry J. Snaith, Werner Egger

Research output: Contribution to journalArticlepeer-review

54 Citations (Scopus)
93 Downloads (Pure)

Abstract

Perovskite photovoltaics advance rapidly, but questions remain regarding point defects: while experiments have detected the presence of electrically active defects no experimentally confirmed microscopic identifications have been reported. Here we identify lead monovacancy (V Pb) defects in MAPbI 3 (MA = CH 3NH 3 +) using positron annihilation lifetime spectroscopy with the aid of density functional theory. Experiments on thin film and single crystal samples all exhibited dominant positron trapping to lead vacancy defects, and a minimum defect density of ~3 × 10 15 cm −3 was determined. There was also evidence of trapping at the vacancy complex (VPbVI)− in a minority of samples, but no trapping to MA-ion vacancies was observed. Our experimental results support the predictions of other first-principles studies that deep level, hole trapping, VPb2−, point defects are one of the most stable defects in MAPbI 3. This direct detection and identification of a deep level native defect in a halide perovskite, at technologically relevant concentrations, will enable further investigation of defect driven mechanisms.

Original languageEnglish
Article number5566
Number of pages7
JournalNature Communications
Volume12
DOIs
Publication statusPublished - 22 Sept 2021

Keywords

  • Photovoltaics
  • Semiconductors

ASJC Scopus subject areas

  • General Chemistry
  • General Biochemistry,Genetics and Molecular Biology
  • General Physics and Astronomy

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