A Kinetic–Energetic Bottleneck of Charge‐Transfer Injection Governs Energy Loss in Organic Solar Cells

ABSTRACT The charge‐transfer (CT) state in organic solar cells constitutes a kinetic–energetic bottleneck that simultaneously controls charge generation and nonradiative voltage loss. By combining time‐resolved photoluminescence (100 ps–20 ns) with a physics‐constrained Bayesian optimization framework, we show that the multidimensional kinetic network collapses onto a single emergent descriptor: the effective CT injection rate, k CT . Crucially, k CT is not a microscopic rate constant but a renormalized collective parameter arising from the coupled competition among exciton injection, CT population redistribution, and CT nonradiative recombination. Across six donor–acceptor systems spanning nearly two orders of magnitude in k CT , we uncover a universal scaling: each decade increase in injection rate incurs an additional ∼85 meV nonradiative energy loss. This scaling reveals an intrinsic kinetic–energetic trade‐off imposed by the topology of the CT manifold—accelerating injection inevitably amplifies recombination loss. Breaking this bottleneck requires restructuring the CT network to decouple charge dissociation from recombination pathways, offering a route beyond the present voltage ceiling of organic photovoltaics.