Enhanced performance of planar perovskite solar cells based on low-temperature processed TiO2 electron transport layer modified by Li2SiO3

Planar perovskite solar cells based on Li 2 SiO 3 modified TiO 2 electron transport layer are fabricated by one-step method. Here the Li 2 SiO 3 modified TiO 2 films are prepared by a simple soaking process at 65 °C. The effect of Li 2 SiO 3 modification on the photoelectric properties of TiO 2 films and devices has been systematically investigated. Compared to the reference TiO 2 , the modified TiO 2 demonstrates better characteristics such as better surface wetting properties of perovskite precursor, enhanced electron mobility and reduced electron trap state density, which contribute to the favorable photovoltaic performance . At the optimized process , the device based on the modified TiO 2 film yields a champion power conversion efficiency of 18.67%, being much higher than 14.78% of the reference device. The improved performance is primarily attributed to the promoted charge transport and reduced charge recombination in the modified electron transport layer. This work provides a simple route to obtain efficient planar perovskite solar cells by low-temperature process, which will be compatible with flexible plastic substrates in future practical applications.