FRET-Enhanced Singlet Fission in Pentacene Derivatives
arXiv:2505.04334 · doi:10.1002/adom.202503007
Abstract
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 dependence of the SF rate on molecular separation 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.
7 pages, 3 figures, 1 supplementary information