Enhancing small-area and module device performance in organic photovoltaics through insulating polymer-induced manipulation of active layer morphology†

Insulating polymers provide an effective and cost-efficient strategy to enhance organic solar cell (OSC) performance while demonstrating potential for commercial applications. In this study, we systematically explore the incorporation of insulating polymers into the active layer of OSCs, with a particular focus on the effects of polystyrene (PS) on the performance of PM6:Y6BO-based devices. The findings indicate that the addition of PS optimizes phase separation and crystallinity within the active layer, significantly improves exciton separation and charge transport efficiencies, and reduces carrier recombination. In terms of device performance, the addition of PS enhances the short-circuit current density (J_sc) and fill factor (FF), resulting in a notable increase in power conversion efficiency (PCE) from 16.6% to 17.3% for the PM6:Y6BO system. To validate the method's scalability, PS was also incorporated into large-area module devices (17.6 cm²), where a 0.1 mg ml⁻¹ PS addition boosted module efficiency to 15.8%. These findings underscore the crucial role of insulating polymers in manipulating the morphology of the photovoltaic active layer and provide support for their application in the development of high-performance organic solar cell module devices.