Enhanced Lifetime and Photostability with Low-Temperature Mesoporous ZnTiO3 /Compact SnO2 Electrodes in Perovskite Solar Cells.

Perovskite solar cells (PSCs) with power conversion efficiencies (PCEs) of 25 % mainly have SnO2 or TiO2 as electron-transporting layers (ETLs). Now, zinc titanate (ZnTiO3 , ZTO) is proposed as mesoporous ETLs owing to its weak photo-effect, excellent carrier extraction, and transfer properties. Uniform mesoporous films were obtained by spinning coating the ZTO ink and annealed below 150 °C. Photovoltaic devices based on Cs0.05 FA0.81 MA0.14 PbI2.55 Br0.45 perovskite sandwiched between SnO2 -mesorporous ZTO electrode and Spiro-OMeTAD layer achieved the PCE of 20.5 %. The PSCs retained more than 95 % of their original efficiency after 100 days lifetime test without being encapsulated. Additionally, the PSCs retained over 95 % of the initial performance when subjected at the maximum power point voltage for 120 h under AM 1.5 G illumination (100 mW cm-2 ), demonstrating superior working stability. The application of ZTO provides a better choice for ETLs of PSCs.