Use of organic bulk-heterojunction solar cells as selective contacts in wide band-gap perovskite solar cells: advantages and limitations

Abstract

Our work analyses for the first time the kinetics of perovskite/organic photovoltaic (OPV) interfaces with different perovskite I/Br ratios (MAPbI_3−xBr_x, x = 0, 1, 2, and 3) and PM6:Y6 as a bulk heterojunction blend. The aim was to study in depth the combination of a wide band gap perovskite material – that allows large open-circuit voltage – and the PM6:Y6 thin film that accounts for large photocurrents in organic photovoltaics (OPV). Studies of carrier extraction and carrier recombination kinetics, using time resolved spectroscopy under operando conditions, have been performed to understand the charge dynamics in these cells. Comprehension of the processes in this perovskite solar cell configuration allowed us to foresee important differences in the reorganization of the perovskite internal electric field depending on its composition and how the performance is influenced by different degrees of accumulation of electronic charges at selective contacts.