Compact Titania Films by Spray Pyrolysis for Application as ETL in Perovskite Solar Cells

Hybrid perovskite-based solar cells are projected as a potentially viable photovoltaic (PV) technology for large-scale implementation. The electron transport layer (ETL) should be dense and pinhole-free to facilitate efficient electron collection and transport from the perovskite layer to the anode, which is very important for achieving high-performance solar cells. In this study, a compact TiO 2 layer was synthesized by a scalable spray pyrolysis technique. The effect of deposition temperature on the transparency, microstructure, and bandgap of c-TiO 2 film was studied. Pinhole-free nanocrystalline films having > 85% transparency with uniform coverage was obtained on spray pyrolysis at 400°C and annealing at 450°C. Usability of the deposited films as ETL in perovskite solar cells was tested by fabricating solar cells (FTO/c-TiO 2 /FA 0.85 MA 0.15 Pb(I 0.85 Br 0.15 ) 3 /CuSCN/Au) using the deposited films and comparing their performance. Cell efficiency close to 11.75% with a fill factor of 69% was obtained in the cell fabricated using the films deposited at 400°C.