Modifying SnO2 with ammonium polyacrylate to enhance the performance of perovskite solar cells

An electron transport layer (ETL) is vital for extracting carriers in perovskite solar cells (PSCs). SnO2 with high electron mobility and excellent energy level matching with adjacent perovskites has been considered as an ideal electron transport material with excellent application prospects. However, some surface defects always exist on the SnO2 films prepared by a solution method, which will cause non-radiative recombination at the ETL/perovskite interface. Herein, an interfacial engineering strategy is adopted to eliminate the surface defects and improve the interface performance by modifying the SnO2 with ammonium polyacrylate (PANH4). After the PANH4 treatment, the interfacial defects of the SnO2/perovskite film were reduced significantly and the electron transport was effectively facilitated by the denser SnO2 layer, finally improving the power conversion efficiency (PCE) of PSCs. Besides, the grain size of the perovskite increases, simultaneously improving the stability of the device. As a result, the PCE of PSCs with an active area of 0.09 cm2 was increased from 18.91% to 20.70%.