Interfacial modification using ultrasonic atomized graphene quantum dots for efficient perovskite solar cells

Tin dioxide (SnO 2 ) is a promising electron transport material to replace traditional titanium dioxide (TiO 2 ) for fabricating efficient planar perovskite solar cells (PSCs). However, in order to realize process compatibility and larger scale device, low temperature solution processed SnO 2 is normally used, which generates numerous trap states in ETL layer and directly affects the device performance. Here, an interfacial modification strategy proposed, depositing an ultrasonic atomized ultrathin graphene quantum dots (GQDs) layer between tin dioxide (SnO 2 ) and perovskite layer. Ultrasonic atomized deposition can effectively prevent the damage of the surface chemical properties of SnO 2 by aqueous solution. Additionally, we demonstrate that the GQDs change the surface property of SnO 2 film, and optimized the charge transport capability in SnO 2 and perovskite interface. Correspondingly, we obtained a significant power conversion efficiency (PCE) improvement for CH 3 NH 3 PbI 3 -based PSCs from 13.61% to 16.54% and reached a highest steady-state PCE over 16%. We believe that the interfacial modification engineering by means of ultrasonic atomizing process is a promising tactic to obtain efficient perovskite solar cells.