NiO/MAPbI(3-x)Clx/PCBM: a model case for an improved understanding of inverted mesoscopic solar cells.

A spectroscopic investigation focusing on the charge generation and transport in inverted p-type perovskite-based mesoscopic (Ms) solar cells is provided in this report. Nanocrystalline nickel oxide and PCBM are employed respectively as hole transporting scaffold and hole blocking layer to sandwich a perovskite light harvester. An efficient hole transfer process from perovskite to nickel oxide is assessed, through time-resolved photoluminescence and photoinduced absorption analyses, for both the employed absorbing species, namely MAPbI3-xClx and MAPbI3. A striking relevant difference between p-type and n-type perovskite-based solar cells emerges from the study.