Molecular Radiative Funneling Mitigates Multimodal Optical Losses in >19.7% Efficiency Flexible Organic Solar Cells

Recycling plasmonic energy from non-radiative damping is essential for overcoming efficiency limits in plasmon-mediated optoelectronic systems, yet is often restricted by the lack of an integrated pathway that converts near-field dissipation into usable optical output. Here, we establish a plasmon-to-photon relay that bridges the gap between parasitic plasmonic loss and usable photon flux. By tailoring multiple-resonance thermally activated delayed fluorescence (MR-TADF) mediators from a planar H-BN to the sterically expanded TPS-BN, we simultaneously strengthen near-field capture via plasmon-induced resonance energy transfer (PIRET) and preserve high radiative efficiency by suppressing intermolecular exciton loss. Upon integration into silver nanowire-based flexible organic solar cells (FOSCs), this configuration effectively intercepts multimodal optical losses, including interfacial plasmonic dissipation and broadband photon escape, and redirects them into a radiative flux, which are preferential harvested by the active layer. Consequently, this radiative funneling enables a champion device with a record efficiency of 19.75%. This work highlights molecular spatial configuration as a determinant for regulating plasmon-mediated energy flow and spectral distribution in high-performance plasmon-mediated optoelectronic devices.