A universal perovskite/C60 interface modification via atomic layer deposited aluminum oxide for perovskite solar cells and perovskite-silicon tandems

Abstract

The primary performance limitation in inverted perovskite-based solar cells is the interface between the fullerene-based electron transport layers and the perovskite. We developed atomic layer deposited thin AlOX interlayers that reduce nonradiative recombination at the perovskite/C60 interface, resulting in > 60 millivolts improvement in open-circuit voltage and 1% absolute improvement in power conversion efficiency. Surface-sensitive characterizations indicate the presence of a thin, conformally deposited AlOx layer, functioning as a passivating contact. These interlayers work universally using different lead-halide-based absorbers with different compositions where the 1.55 electron volts bandgap single junction devices reach >23% power conversion efficiency. We find a reduction of metallic Pb0 and the compact layer prevents in- & egress of volatile species, synergistically improving the stability. AlOX-modified wide-bandgap perovskite absorbers as a top cell in a monolithic perovskite-silicon tandem enable a certified power conversion efficiency of 29.9% and open-circuit voltages above 1.92 volts for 1.17 square centimeters device area.