Trap engineering using oxygen-doped graphitic carbon nitride for high-performance perovskite solar cells

Trap-assisted non-radiative recombination is one of the main energy loss pathways in metal halide perovskite solar cells (PVSCs). Here in this work, oxygen-doped graphitic carbon nitride (g-C3N4-O) is introduced into the commonly used SnO2 electron transport layer (ETL) as an additive to engineer the traps at the ETL/perovskite interface. The interaction between g-C3N4-O and SnO2 could effectively and simultaneously mitigate the uncoordinated Sn dangling bonds and the -OH groups, which are the two dominant deep-traps at the ETL/perovskite interface. Trap-engineered PVSCs show optimized electrical properties with matched energy band alignment, improved electron transport and extended carrier lifetime. As a result, binary PVSCs modified with g-C3N4-O achieve a champion power conversion efficiency of over 21% and demonstrate high environmental stability.

Automated summary

In this work, oxygen-doped graphitic carbon nitride (g-C3N4-O) was introduced as an additive in the SnO2 electron transport layer (ETL) to optimize the traps at the ETL/perovskite interface. The interaction between g-C3N4-O and SnO2 effectively reduced the uncoordinated Sn dangling bonds and -OH groups, which are the main deep-traps at the ETL/perovskite interface. The trap-engineered PVSCs exhibited improved electrical properties, including matched energy band alignment, enhanced electron transport, and prolonged carrier lifetime. As a result, g-C3N4-O modified binary PVSCs achieved a champion power conversion efficiency of over 21% and demonstrated high environmental stability.