Screen-printed electron transport layer for efficient air-processed perovskite solar cells

Abstract

We present a robust and screen-printed electron transport layer (ETL) by modulating mesoporous TiO2 scaffold with SnO2. This hybrid modification strategy simultaneously enhances the electrical conductivity and passivates interfacial defects within the ETL, thereby reducing trap-assisted recombination while improving electron extraction efficiency. Notably, the incorporation of SnO2 raises the Fermi level and lowers the valence band maximum of TiO2, resulting in a near-ideal energy-level alignment that facilitates efficient electron extraction and effective hole blocking. The optimized devices, fabricated under ambient conditions, achieve a champion power conversion efficiency of 24.4% and maintain an efficiency of 20.4% even at an ETL thickness of over 1 micron.