Weak Absorptive Component Boosts Exciton Dissociation in Indoor Organic Photovoltaics

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 weak 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 weak absorptive third component, the ternary devices exhibit a power conversion efficiency increase from 24.7% to 26.2%. These findings highlight the potential of weak absorptive components in optimizing energy transfer processes and overcoming the limitations of indoor light harvesting in OPV systems.