Efficient planar perovskite solar cells using solution-processed amorphous WOx/fullerene C60 as electron extraction layers

In perovskite solar cells (PSCs), an electron extraction layer (EEL) plays a crucial role in extracting electrons from the perovskite layer and blocking the holes in it from recombining with the electrons in the fluorine-doped tin oxide (FTO). Amorphous tungsten oxide (WOx) has been successfully employed as EEL in PSCs. However, the WOx device suffers from inherent charge recombination, resulting in low open circuit voltage (V-oc) and fill factor (FF). Here, we report that WOx/fullerene C60 can work coactively to further enhance the performance of PSCs. PSC with WOx/C-60 EELs showed a power conversion efficiency of 16.07% with an open circuit voltage of 0.93 V, a short-circuit current density of 22.15 mA/cm(2), and a fill factor of 0.78, which were higher than those of PSCs with pristine WOx EEL. Our results suggest that using WOx/C-60 as EELs offer a simple and effective approach for fabricating high-performance and lowtemperature PSCs. (C) 2017 Elsevier B. V. All rights reserved.