Dual Additives - Enabled Precision Regulation Over Molecular Packing and Morphology for Organic Solar Cells

Organic solar cells (OSCs) face a critical challenge in enhancing device performance through precise control of the active layer morphology. Traditional solvent additive methods can effectively optimize phase separation; however, the use of a single additive is limited by strong acceptor-acceptor interactions, making it difficult to achieve precise control over a nanoscale interpenetrating network. To tackle this problem, this study introduces a synergistic strategy involving the combination of the volatile solid additive dibenzyl sulfide (DBS) and the commonly used solvent additive 1-chloronaphthalene (CN), aiming to precisely modulate the morphology of the PM6/Y6 active layer. The results reveal that the synergistic action of DBS and CN effectively governs ordered molecular aggregation, optimizing the active layer’s morphology and phase separation. By extending the film-forming duration, this strategy promotes Y6 nucleation and enhances crystallinity, culminating in the formation of an optimal nanoscale interpenetrating network structure. Ultimately, the optimized active layer morphology effectively enhances exciton dissociation while suppressing bimolecular recombination, enabling a power conversion efficiency (PCE) of 17.09%. This strategy provides a simple and efficient method for regulating the morphology of the active layer, which helps in the design and optimization of more efficient organic photovoltaic materials and devices.