Embedding of WO₃ nanocrystals with rich oxygen-vacancies in solution processed perovskite film for improved photovoltaic performance

Seeking strategies of promoting the charge separation and transport of the photo-active layer has been always of significance for the development of high-performance optoelectronic devices. We herein demonstrate an effective way of decorating WO₃ nanocrystals in perovskite films for boosted photogenerated carriers transport. The WO₃ nanocrystals are generated by a simple technique of pulsed laser irradiation in liquid, then introduced into the perovskite film based on the anti-solvent approach. Such decoration is found helpful for the increase of the short-circuit current density (J_sc) of the device, which leads to the increase of the photoconversion efficiency (PCE) from 17.72% to 19.29%. The improved PCE is mainly due to the decoration of the WO₃ at the grain boundaries of perovskite films that facilitates the charge transport between the adjacent grains, which is evidenced by the quenching of the film photoluminescence, shortened carrier lifetime, and increased carrier mobility. We thus believe our study provides an effective way of embedding ordinary metal oxides in perovskite films for enhanced optoelectronic performance.