Fullerene derivative, such as Bis[C60]PCBM(PCBM), is widely used as an electron-transport layer (ETL) in inverted perovskite solar cell (PSC). However, its low electron mobility, complexity in achieving quality film formation, and severe nonradiative recombination at perovskite/PCBM interface due to the large electron capture region, lead to lower efficiency for inverted PSCs compared to the normal structures.[1]
![Bis-[60]PCBM](https://www.chemicalbook.com/CAS/20180906/GIF/1048679-01-1.gif)