Evolution of charge pathways through amorphous aluminum–cerium electrode for stable organic photovoltaics

Abstract

In this study, an amorphous aluminum–cerium (AlCe) thin film is sputtered onto a MoO_x layer to serve as a stable electrode in organic photovoltaic (OPV) devices. The absence of grain boundaries in the amorphous metal provides a chemically stable interface that enhances the long-term stability of OPV devices. Amorphous metals in thin-film devices typically trade performance for chemical stability. In addition, cerium-based amorphous metal was found to interact with the adjacent MoO_x layer by inducing shifts in oxidation states through X-ray photoelectron spectroscopy. This phenomenon resulted in an unusual recovery in device performance after storage in ambient air. Through comprehensive compositional and electrical analyses of the amorphous electrode and interlayer, this study highlights the potential of AlCe thin films to enhance both the stability and performance recovery of OPV devices, offering a promising approach for durable, high-performance OPVs. This research provides stable and efficient metal electrodes for next-generation organic optoelectronic devices.