New Pb-Free Stable Sn-Ge Solid Solution Halide Perovskites Fabricated by Spray Deposition

Adi Kama, Shay Tirosh, Anat Itzhak, Michal Ejgenberg, David Cahen

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

Abstract

Considering the toxicity of lead ions, substituting Pb with nontoxic elements in halide perovskites, HaPs, has become one of the most significant challenges associated with these materials. Here, we report on replacing Pb with Sn and Ge, focusing on an all-inorganic HaP, CsSnxGe1-xBr3, and using a multihead spray deposition setup for thin-film formation to overcome the low solubility of the precursors and improve film coverage. We find that, in this way, we can form CsSnxGe1-xBr3 films up to high x values as homogeneous solid solutions; i.e., we obtain a range of compositions with one crystal structure (rather than clusters of two phases). The cubic structure of pure CsSnBr3 is maintained up to 77 atom % Ge, with the lattice spacing decreasing with increasing Ge concentration. The optical band gap is tunable between 1.8 and 2.5 eV, from pure Sn to pure Ge HaP. Most importantly, the perovskite structural stability increases with increasing concentration of Ge, with less oxidation of both Ge and Sn to the +4 state, which can be ascribed to less octahedral tilting and stronger bonding. Electrical and electronic transport measurements show the potential of these materials as Pb-free absorbers for solar cells, particularly, given their band gap range as the top cell of a tandem photovoltaic device.

Original languageEnglish
Pages (from-to)3638-3646
Number of pages9
JournalACS Applied Energy Materials
Volume5
Issue number3
DOIs
StatePublished - 28 Mar 2022

Bibliographical note

Publisher Copyright:
© 2022 The Authors. Published by American Chemical Society

Keywords

  • Halide perovskite
  • Pb-free
  • Sn-ge
  • Solar cell
  • Spray deposition
  • Stability

Fingerprint

Dive into the research topics of 'New Pb-Free Stable Sn-Ge Solid Solution Halide Perovskites Fabricated by Spray Deposition'. Together they form a unique fingerprint.

Cite this