Indexed on: 14 Dec '18Published on: 14 Dec '18Published in: Nanotechnology
Electron transport layer (ETL) plays an important role in realizing efficient and stable perovskite solar cells. There are continuous efforts in developing new types of low cost ETLs with improved conductivity and compatibility with perovskite and the conducting electrode. Here, in order to obtain high efficient and stable perovskite solar cells on ZnO: Al (AZO) substrate, reduced graphene oxide (rGO) is incorporated into SnO2 nanoparticles to form composite ETL. For planar perovskite solar cell on AZO substrates, SnO2-rGO with a low incorporation ratio of 3wt% rGO significantly enhances the device short circuit current density (Jsc) and the fill factor (FF) when compared to the device with pristine SnO2 ETL, leading to an overall power conversion efficiency (PCE) of 16.8% with negligible hysteresis. The effectiveness of the excited charge transfer process of SnO2-rGO ETL is revealed by time-resolved photoluminescence decay (TRPL), and by electrochemical impedance spectrum (EIS) measurements. Furthermore, the solar cell stability is also enhanced due to the incorporation of rGO in the ETL. This work provides a low cost and effective ETL modification strategy for achieving high performance planar PSCs. © 2018 IOP Publishing Ltd.