Interconnected SnO2 Nanocrystals Electron Transport Layer for Highly Efficient Flexible Perovskite Solar Cells

This study reports on interconnected SnO 2 electron transport layers (composed of presynthesized SnO 2 nanocrystals interconnected by amorphous phase SnO x ) processed at low temperature (120 °C) for highly efficient flexible perovskite solar cells. Herein, the amorphous phase SnO x serves as an effective binder to connect the SnO 2 nanocrystals to obtain ultra-smooth electron transport layers. Further characterization of the charge carrier kinetics at the perovskite/electron transport layer interface confirms that the interconnected SnO 2 nanocrystals layer facilitates electron extraction and retards nonradiative charge carrier recombination. Consequently, a power conversion efficiency of 16.29% is achieved for flexible perovskite solar cells using the interconnected SnO 2 electron transport layer on indium tin oxide/polyethylene terephthalate substrates.