Suppressed Decomposition of Perovskite Film on ZnO Via a Self-Assembly Monolayer of Methoxysilane

Although ZnO is an attractive electron transport layer (ETL) for high performance perovskite solar cells (PSCs) due to its suitable energy structure, high electron mobility, and low-temperature process, perovskite films on ZnO are decomposed rapidly as the substrate is heated over 90 °C. However, the annealing temperature higher than 90 °C is mandatory to produce high quality perovskite films. Here, for the first time, the use of an ultra-thin self-assembly monolayer (SAM) of methoxysilane on ZnO ETL to suppress the decomposition of perovskite films is reported. A self-form solvent annealing (SFSA) method is also carried out to improve the crystal quality of perovskite, and the champion device of SAM modified ZnO based PSCs yields a PCE of 18.34%. All these processes are conducted at low temperature and compatible with fabrication of flexible devices.