Electron, Energy, and Hole Transfer Dynamics in D1:D2:A Ternary Organic Solar Cells

Ternary organic solar cells (OSCs) offer enhanced light harvesting and tunable charge transport, but their multichannel energy and charge transfer processes remain poorly understood. This study employed a model system composed of donors (PCz, PM6) and acceptor (Y6) to investigate the excited state behavior in ternary blend films and elucidate the energy and charge transfer pathways among the individual components. The results show that a sequential excitation energy transfer and electron transfer process occurs from PCz to PM6 and subsequently to Y6, while hole transfer (HT) occurs from Y6 to both PM6 and PCz. The effect of PCz content on the energy transfer efficiency and HT rate was explored. The data demonstrate that the ternary system exhibits a faster HT rate and higher energy transfer efficiency, achieving a maximum power conversion efficiency of 17.64%. This work reveals excited-state dynamics in ternary OSCs and offers guidance for designing and optimizing multicomponent systems.