Electron transport interface engineering with pyridine functionalized perylene diimide-based material for inverted perovskite solar cell

Charge-transport layer engineering is proved to be as important as the optimization of perovskite light harvesting layer in achieving high power conversion efficiency for the inverted perovskite solar cells (p-i-n PSCs). This work mainly focuses on electron transport interface engineering and demonstrates a pyridine functionalized perylene diimide-based electron transport material (ETM), termed SFX-Py-PDI2. Benefiting from the high electron mobility, suitable energy arrangement and defect passivating effect, p-i-n PSCs with SFX-Py-PDI2 as ETM produce a desired PCE over 19% surpassing PC61BM based devices. Especially noteworthy is that introducing SFX-Py-PDI2 into perovskite film through anti-solvent treatment together with PC61BM as ETM further boost the PCE of p-i-n PSCs over 21%. Moreover, the SFX-Py-PDI2 based device showed impressive long-term stability at unencapsulated condition, maintaining over 80% initial PCE after aging for 1000 h in 65 ℃, 50–60% RH environment.