22.43%-Efficiency flexible modification-free perovskite solar cells with a uniform and anti-reflective ITO/SiO2/PET/SiO2 substrate

Abstract

Flexible perovskite solar cells (PSCs) are at the forefront of research into perovskite photovoltaics. Both high power conversion efficiency (PCE) and simple manufacturing without perovskite modifications are significant for the adaptation of flexible PSCs. However, flexible modification-free PSCs suffer from a PCE of no higher than 21.1%. Herein, we report a highly efficient flexible modification-free PSC with an electrode-silica-substrate via magnetron sputtering. We explored the underlying mechanism of how indium tin oxide (ITO) electrodes affected and increased the device efficiency, and found the key factors that determined the device efficiency. The thermoplastic substrates coated with electrode and silica not only had a low optical reflectance for high transparencies, but also showed a uniform and peak- and valley-free morphology and distribution-uniform surface potentials for a better perovskite with enhanced crystallinity and few defects. The flexible modification-free PSCs exhibited an excellent PCE of 22.43%. 22.43% is the highest PCE among these flexible modification-free PSCs reported so far. Furthermore, the flexible PSCs exhibited increases in operational stability, storage stability, air stability and mechanical flexibility. This work significantly guides the development of ITO products in high-performance flexible modification-free PSCs.