TiO2/ZnO/TiO2sandwich multi-layer films as a hole-blocking layer for efficient perovskite solar cells

A continuous and compact hole-blocking layer is crucial to prevent photocurrent recombination at the photoanode/electrode interface of high-performance mesostructure perovskite-based solar cells. Novel TiO2/ZnO/TiO2 sandwich multi-layer compact film prepared as hole-blocking layer for perovskite solar cell. Herein, TiO2, ZnO, and TiO2 layers were successfully deposited by spin-coating onto FTO glass substrate in sequence. The fill factor and power conversion efficiency of the perovskite solar cell are remarkably improved by the employment of a TiO2/ZnO/TiO2 sandwich compact layer. Perovskite solar cell based on TiO2/ZnO/TiO2 sandwich film has been observed to exhibit maximum incident-photon-to-current conversion efficiency in the visible region (400–780 nm) and reach a power conversion efficiency of 12.8% under AM1.5G illumination. Copyright © 2016 John Wiley & Sons, Ltd.