Eco-friendly volatile additive enabling efficient large-area organic photovoltaic module processed with non-halogenated solvent

Abstract

The pursuit of sustainable manufacturing for organic solar cells (OSCs) has prompted the exploration of environmentally friendly, non-halogenated solvents. However, contemporary OSCs processed with these solvents often require the inclusion of toxic halogenated additives to optimize photovoltaic performance. In this study, we devised a processing method that incorporates not only a non-halogenated solvent but also a non-halogenated additive. The introduction of the eco-friendly menthol (MT) effectively mitigates detrimental disordered aggregation during film formation by leveraging its strong polarity to enhance acceptor crystallization, thereby optimizing the donor–acceptor morphology. These advancements ultimately lead to more efficient exciton dissociation and charge carrier transport, resulting in the realization of large-area organic photovoltaic modules (19.31 cm²) with a notable power conversion efficiency (PCE) of 15.74%. To the best of our knowledge, this PCE represents the highest reported value for large-area modules processed with non-halogenated solvents and is comparable to state-of-the-art organic photovoltaic modules processed with conventional halogenated solvents. This research underscores the significant potential of fully non-halogenated processing in achieving sustainable manufacturing for high-performance OSCs.