2025/05/07 by Kefer, Oskar, Ludwig, Philipp, Dittmar, Benedikt +5
#Applied Physics (physics.app-ph) #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci)
paper · doi:10.48550/arxiv.2505.04334
Conversion of solar energy with high quantum efficiencies is a key challenge in energy technologies. Excitation energy transfer (EET) mechanisms, such as Förster resonance energy transfer (FRET), play a crucial role in facilitating minimal energy loss in biological light-harvesting systems by directing excitation energy to conversion centers. Inspired by this, we show that singlet fission (SF) sensitizers are multi-exciton generation centers, to which surrounding molecules funnel excitation energy via FRET. We study the impact of such EET on SF using two structurally distinct yet optically similar pentacene derivatives: a stability-enhanced ''Geländer'' pentacene, and the well-studied TIPS-pentacene. Transient absorption spectroscopy reveals a R6 dependence of the SF rate on molecular separation R in binary acene:polymethylmetacrylate thin film blends, which is typical for FRET. Optimizing FRET is a promising direction for future improvements in light harvesting using SF materials, inspired by natural light-harvesting complexes.