Enhanced Organic and Perovskite Solar Cell Performance through Modification of the Electron Selective Contact with a Bodipy-Porphyrin Dyad

Abstract

Photovoltaic devices based on organic semiconductors and organo-metal halide perovskites have not yet reached the theoretically predicted power conversion efficiencies while they still exhibit poor environmental stability. Interfacial engineering using suitable materials has been recognized as an attractive approach to tackle the above issues. We introduce here a zinc porphyrin-triazine-bodipy donor-π bridge-acceptor dye as a universal electron transfer mediator in both organic and perovskite solar cells. Thanks to its "push-pull" character, this dye enhances electron transfer from the absorber layer towards the electron selective contact thus improving the device photocurrent and efficiency. The direct result is a more than 10% average power conversion efficiency enhancement in both fullerene (from 8.65 to 9.80 %) and non-fullerene (from 7.71 to 8.73%) based organic solar cells as well as in perovskite ones (from 14.56 to 15.67%), proving the universality of our approach. Concurrently, by forming a hydrophobic network on the surface of metal oxide substrates it improves the nanomorphology of the photoactive overlayer and contributes to efficiency stabilization. The fabricated devices of both kinds preserved more than 85% of their efficiency upon exposure to ambient conditions for more than 600 hours without any encapsulation.