Solution-processed nanostructured zinc oxide cathode interfacial layers for efficient inverted organic photovoltaics

Abstract

Inverted organic photovoltaic (OPV) cells based on poly(3-hexylthiophene) (P3HT) as an electron donor and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) as an electron acceptor, were fabricated and characterized. To improve the photovoltaic performance, interface control using either dense or nanostructured ZnO films as cathode buffer layers for effective electron transport was demonstrated, while an under-stoichiometric transition metal oxide, such as MoOx, was employed as the anode buffer layer for efficient hole extraction. Incorporation of a nanostructured ZnO interlayer enhanced electron–hole dissociation by enabling a larger interfacial contact with the active layer, that results in increased short-circuit current density (Jsc) and eventually contributing to higher power conversion efficiency (PCE).