Dependence of material properties and photovoltaic performance of triple cation tin perovskites on the iodide to bromide ratio

Stefan Weber, Thomas Rath*, Birgit Kunert, Roland Resel, Theodoros Dimopoulos, Gregor Trimmel

*Corresponding author for this work

Research output: Contribution to journalArticle

Abstract

Abstract: In this work, the influence of a partial introduction of bromide (x = 0–0.33) into MA0.75FA0.15PEA0.1Sn(BrxI1−x)3 (MA: methylammonium, FA: formamidinium, PEA: phenylethylammonium) triple cation tin perovskite on the material properties and photovoltaic performance is investigated and characterized. The introduction of bromide shifts the optical band gap of the perovskite films from 1.29 eV for the iodide-based perovskite to 1.50 eV for the perovskite with a bromide content of x = 0.33. X-ray diffraction measurements reveal that the size of the unit cell is also gradually reduced based on the incorporation of bromide. Regarding the photovoltaic performance of the perovskite films, it is shown that already small amounts of bromide (x = 0.08) in the perovskite system increase the open circuit voltage, short circuit current density and fill factor. The maximum power conversion efficiency of 4.63% was obtained with a bromide content of x = 0.25, which can be ascribed to the formation of homogeneous thin films in combination with higher values of the open circuit voltage. Upon introduction of a higher amount of bromide (x = 0.33), the perovskite absorber layers form pinholes, thus reducing the overall device performance. Graphic abstract: [Figure not available: see fulltext.].

Original languageEnglish
Pages (from-to)1921-1927
Number of pages7
JournalMonatshefte fur Chemie
Volume150
Issue number11
DOIs
Publication statusPublished - 1 Nov 2019

Keywords

  • Lead-free perovskite
  • Material science
  • Semiconductors
  • Solar cell

ASJC Scopus subject areas

  • Chemistry(all)

Fields of Expertise

  • Advanced Materials Science

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