The interfacial compatibility between compact TiO
2
and perovskite layers is critical for the performance of planar heterojunction perovskite solar cells (PSCs). A compact TiO
2
film employed as an electron-transport layer (ETL) was modified using 3-aminopropyl trimethoxy silane (APMS) hydrolysate. The power conversion efficiency (PCE) of PSCs composed of an APMS-hydrolysate-modified TiO
2
layer increased from 13.45 to 15.79%, which was associated with a significant enhancement in the fill factor (FF) from 62.23 to 68.04%. The results indicate that APMS hydrolysate can enhance the wettability of γ-butyrolactone (GBL) on the TiO
2
surface, form a perfect CH
3
NH
3
PbI
3
film, and increase the recombination resistance at the interface. This work demonstrates a simple but efficient method to improve the TiO
2
/perovskite interface that can be greatly beneficial for developing high-performance PSCs.
Enhanced efficiency and stability of inverted perovskite solar cells by interfacial engineering with alkyl bisphosphonic molecules
