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.