Solvent-Mediated Crystallization of CH3NH3SnI3 Films for Heterojunction Depleted Perovskite Solar Cells

Feng Hao, Konstantinos Stoumpos, Peijun Guo, Nanjia Zhou, Tobin Jay Marks, R P H Chang, Mercouri Kanatzidis*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

333 Scopus citations

Abstract

Organo-lead halide perovskite solar cells have gained enormous significance and have now achieved power conversion efficiencies of ∼20%. However, the potential toxicity of lead in these systems raises environmental concerns for widespread deployment. Here we investigate solvent effects on the crystallization of the lead-free methylammonium tin triiodide (CH3NH3SnI3) perovskite films in a solution growth process. Highly uniform, pinhole-free perovskite films are obtained from a dimethyl sulfoxide (DMSO) solution via a transitional SnI2·3DMSO intermediate phase. This high-quality perovskite film enables the realization of heterojunction depleted solar cells based on mesoporous TiO2 layer but in the absence of any hole-transporting material with an unprecedented photocurrent up to 21 mA cm-2. Charge extraction and transient photovoltage decay measurements reveal high carrier densities in the CH3NH3SnI3 perovskite device which are one order of magnitude larger than CH3NH3PbI3-based devices but with comparable recombination lifetimes in both devices. The relatively high background dark carrier density of the Sn-based perovskite is responsible for the lower photovoltaic efficiency in comparison to the Pb-based analogues. These results provide important progress toward achieving improved perovskite morphology control in realizing solution-processed highly efficient lead-free perovskite solar cells.

Original languageEnglish (US)
Pages (from-to)11445-11452
Number of pages8
JournalJournal of the American Chemical Society
Volume137
Issue number35
DOIs
StatePublished - Sep 9 2015

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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