Dual Function Modification of Cs2CO3 for Efficient Perovskite Solar Cells

Organic-inorganic hybrid perovskite solar cells (PeSCs) attract much attention in the field of solar cells due to their excellent photovoltaic performance. Many efforts have been devoted to improving their power conversion efficiency (PCE). However, few works focus on simultaneously improving their electrical and optical property. Herein, a simple strategy is proposed to improve the PCE from 19.8% of a reference device to 22.9%, by utilizing cesium carbonate (Cs2CO3) to modify indium tin oxide (ITO) substrate. The insertion of a Cs2CO3-modification layer between ITO substrate and SnO2 electron transport layer simultaneously offers two benefits: improving the electron extraction capability and adjusting the light field distribution in the device. The optical optimization effect of Cs2CO3 revealed in this work has not been reported before. This work provides a new and simple strategy to obtain high performance PeSCs by improving the electrical and optical properties of the devices at the same time.