Highly Reproducible Sn-Based Hybrid Perovskite Solar Cells with 9% Efficiency

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Abstract

The low power conversion efficiency (PCE) of tin-based hybrid perovskite solar cells (HPSCs) is mainly attributed to the high background carrier density due to a high density of intrinsic defects such as Sn vacancies and oxidized species (Sn4+) that characterize Sn-based HPSCs. Herein, this study reports on the successful reduction of the background carrier density by more than one order of magnitude by depositing near-single-crystalline formamidinium tin iodide (FASnI(3)) films with the orthorhombic a-axis in the out-of-plane direction. Using these highly crystalline films, obtained by mixing a very small amount (0.08 m) of layered (2D) Sn perovskite with 0.92 m (3D) FASnI(3), for the first time a PCE as high as 9.0% in a planar p-i-n device structure is achieved. These devices display negligible hysteresis and light soaking, as they benefit from very low trap-assisted recombination, low shunt losses, and more efficient charge collection. This represents a 50% improvement in PCE compared to the best reference cell based on a pure FASnI(3) film using SnF2 as a reducing agent. Moreover, the 2D/3D-based HPSCs show considerable improved stability due to the enhanced robustness of the perovskite film compared to the reference cell.

Original languageEnglish
Article number1702019
Number of pages10
JournalAdvanced Energy Materials
Volume8
Issue number4
DOIs
Publication statusPublished - 5-Feb-2018

Keywords

  • background charge carrier density
  • crystallinity
  • grain boundaries
  • tin perovskite solar cells
  • tin vacancies
  • TIN HALIDE PEROVSKITES
  • PHOTOVOLTAIC PERFORMANCE
  • THIN-FILMS
  • STABILITY
  • FABRICATION
  • HYSTERESIS
  • CONDUCTOR
  • BEHAVIOR
  • DEFECTS

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