Subphthalocyanine-based electron-transport materials for perovskite solar cells

Non-fullerene ETMs are emerging as a hot topic in the field of PSCs due to the inherent shortcomings of fullerene derivatives. Herein, the potential of SubPcs as ETMs in PSCs has been evaluated. To this end, ETMs based on two SubPcs (with chlorine or fluorine at the axial position) have been incorporated in PSCs, where the perovskite is deposited by either solution processing (CsFAMAPbIBr) or thermal evaporation (MAPI). The device performance and morphology of these devices are analyzed in depth using several techniques, and the interfacial effects induced by the SubPcs are studied using PL and TR-PL. In all cases, the SubPc with axial chlorine led to higher efficiencies. Thus, a maximum PCE of 10.8% was achieved with the champion device using a SubPc/C-60 double-layer ETM.