Ruthenium doped mesoporous titanium dioxide for highly efficient, hysteresis-free and stable perovskite solar cells

The electron transporting layer (ETL) plays a vital role in the power conversion efficiency (PCE) of perovskite solar cells (PSCs). We have demonstrated the synthesis of ruthenium doped mesoporous TiO2 (Ru-TiO2) and their utility as ETLs for PSCs. The doping effects of Ru4+ on the electronic and photovoltaic properties of mesoporous TiO2 (mp-TiO2) have been investigated as well. The highest PCE of 18.94% was obtained with 0.1 M Ru-TiO2 PSCs exhibiting an open circuit voltage (VOC) of 1.128 V, current density (JSC) of 22.55 mA cm−2, and fill factor (FF) of 76.55%, whereas the conventional mesoporous PSCs showed PCE = 16.80%, VOC = 1.095 V, JSC = 21.50 mA cm−2, and FF = 70.01%. Note that the 0.1 M Ru-TiO2 device shows high PCE with negligible hysteresis index, high reproducibility and more stability as compared to conventional mesoporous PSCs.