Electron Transport Layer-Free Solar Cells Based on Perovskite-Fullerene Blend Films with Enhanced Performance and Stability

Abstract

The solution processing of pinhole-free methylammonium lead triiodide perovskite-C₇₀ fullerene (MAPbI₃ :C₇₀ ) blend films on fluorine-doped tin oxide (FTO)-coated glass substrates is presented. Based on this approach, a simplified and robust protocol for the preparation of efficient electron-transport layer (ETL)-free perovskite solar cells is described. Power conversion efficiency (PCE) of 13.6 % under AM 1.5 G simulated sunlight is demonstrated for these devices. Comparative impedance spectroscopy and photostability analysis of the MAPbI₃ :C₇₀ and single MAPbI₃ films compared with conventional compact TiO₂ ETL-based devices are shown. The beneficial impact of using MAPbI₃ :C₇₀ blend films is emphasized.

Keywords: blend films; co-solvent; fullerene; perovskite; stability.