Inverted (p-i-n) perovskite solar cells using a low temperature processed TiO x interlayer.

In this article, we present the improvement in device performance and stability as well as reduction in hysteresis of inverted mixed-cation-mixed-halide perovskite solar cells (PSCs) using a low temperature, solution processed titanium oxide (TiO x ) interlayer between [6,6]-phenyl-C61 butyric acid methyl ester (PCBM) and an Al electrode. Upon applying a TiO x interlayer, device resistance was reduced compared to that of the control devices, which results in improved rectification of the characteristic current density-voltage (J-V) curve and improved overall performance of the device. PSCs with the TiO x interlayer show an open-circuit voltage (V oc) of around 1.1 V, current density (J sc) of around 21 mA cm-2, fill factor (FF) of around 72% and enhanced power conversion efficiency (PCE) of 16% under AM1.5 solar spectrum. Moreover, devices with the TiO x interlayer show improved stability compared to devices without the TiO x interlayer. This finding reveals the dual role of the TiO x interlayer in improving device performance and stability.