Harvesting light with polaritons

When placing an organic material inside an optical cavity, molecular and cavity mode excitations can hybridize into polaritons that provide the coupled system with new, sometimes enhanced, photochemical properties [1]. However, the mechanism by which the light-matter interaction changes the photochemistry of the molecules, remains unknown. Here, using molecular dynamics computer simulations, we demonstrate in atomic detail how collectively coupling a mixture of photoreactive and non-photoreactive molecules to a cavity can enhance artificial light harvesting in a way that resembles natural light-harvesting. Our results suggest that collective strong coupling not only enhances photon absorption but also provides a mechanism to transfer that photon into a photoreactive molecule and trigger the photochemical reaction that ultimately captures the energy in a chemical bond. [1] F. J. Garcia-Vidal, C. Ciuti and T. Ebbesen. Manipulating matter by strong coupling to vacuum fields. Science, 373: eabd0336, 2021