A Rutile TiO₂ Electron Transport Layer for the Enhancement of Charge Collection for Efficient Perovskite Solar Cells

Interfacial charge collection efficiency has demonstrated significant effects on the power conversion efficiency (PCE) of perovskite solar cells (PSCs). Herein, crystalline phase‐dependent charge collection is investigated by using rutile and anatase TiO 2 electron transport layer (ETL) to fabricate PSCs. The results show that rutile TiO 2 ETL enhances the extraction and transportation of electrons to FTO and reduces the recombination, thanks to its better conductivity and improved interface with the CH 3 NH 3 PbI 3 (MAPbI 3 ) layer. Moreover, this may be also attributed to the fact that rutile TiO 2 has better match with perovskite grains, and less trap density. As a result, comparing with anatase TiO 2 ETL, MAPbI 3 PSCs with rutile TiO 2 ETL delivers significantly enhanced performance with a champion PCE of 20.9 % and a large open circuit voltage ( V OC ) of 1.17 V.