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Transport of excitons and charge carriers in molecular systems can be enhanced by coherent coupling to photons, giving rise to the formation of hybrid excitations known as polaritons. Such enhancement has far-reaching technological implications; however, the enhancement mechanism and the transport nature of these hybrid excitations remain elusive. Here we map the ultrafast spatiotemporal dynamics of polaritons formed by mixing surface-bound optical waves with Frenkel excitons in a self-assembled molecular layer, resolving polariton dynamics in energy/momentum space. We find that the interplay between the molecular disorder and long-range correlations induced by coherent mixing with light leads to a mobility transition between diffusive and ballistic transport, which can be controlled by varying the light–matter composition of the polaritons. Furthermore, we show that coupling to light enhances the diffusion coefficient of molecular excitons by six orders of magnitude and even leads to ballistic flow at two-thirds the speed of light.

Metallic nanostructures are well known for their potential to enhance resonant energy transfer between chromophores, mediated by their plasmonic field. In most cases, the distances for efficient energy transfer are determined by the dimensions of the structure, making dissipation in the metal dominant when long-range energy transfer is desired. Here, we propose and study a new mechanism for long-distance energy transfer, which can lead to highly efficient energy transfer over distances comparable to the optical wavelength, based on hybrid photonic–plasmonic modes in metal-dielectric structures. We study such structures theoretically and characterize the energy-transfer processes in them, showing that within these structures, energy can be funneled with ∼25% efficiency over a range of about 150 nm, with minimal dependence on the location of the acceptor molecules inside the structure. Finally, we demonstrate this new mechanism experimentally, providing a proof-of-concept for long-distance energy transfer in such structures. Our multilayer system is compatible with standard photovoltaic and organic light-emitting diodes and therefore the mechanism presented can be readily employed in such organic optoelectronic devices to improve their performance.

We report the synthesis of a series of the oxygen-depleted conjugated 5,5′-Bicalix[4]arene compounds bearing various substituents at the terminal positions of the conjugated chain and their fluorescence response to the presence of a cationic N-methylpyridinium guest. The complexation of this cation within the bicalixarene cavity results in the fluorescence quenching, with the host molecules bearing electron-donating groups demonstrating a stronger fluorescence response. These results show the importance of the electronic effects on the host–guest complexation within the hydrophobic calixarene scaffolds.