Indoor organic photovoltaic (OPV) cells have emerged as promising candidates for harvesting energy from artificial light sources. However, the limited spectral range and low photon flux of indoor light sources restrict the photocurrent and power output of these devices. In this work, we investigate the role of a non-absorptive third component in enhancing exciton dissociation and improving indoor OPV performance. By introducing eC9-2Cl into a D18-Cl:F-BTA3 binary system, we create a ternary blend that demonstrates significant improvements in device efficiency. Transient absorption spectroscopy and time-resolved photoluminescence measurements reveal that eC9-2Cl facilitates efficient energy transfer and exciton dissociation. Under indoor lighting conditions, where eC9-2Cl acts as a non-absorptive third component, the ternary devices exhibit a power conversion efficiency increase from 24.7% to 27.2%. These findings highlight the potential of non-absorptive components in optimizing energy transfer processes and overcoming the limitations of indoor light harvesting in OPV systems.

The morphology of the active layer plays a crucial role in the performance of organic photovoltaics. Although volatile additives are commonly used to manipulate the morphology, their mechanism of action remain poorly understood. In this study, we conducted a systematic exploration of the mechanism of the traditional volatile additive 1-CN in film formation kinetics of typical PM6:Y6 system. We found that 1-CN induces a secondary aggregation effect, improving film morphology and promoting face-on crystalline orientation. Through elucidating its impact on exciton dynamics, we established a link between morphology optimization and increased exciton diffusion length and accelerated charge separation. Our findings unveil the unique mechanism of action of volatile additive, providing a new perspective for improving the morphology and enhancing the performance of organic photovoltaic devices.