Photocurrent generation following long-range propagation of organic exciton–polaritons

Abstract

Natural photosynthesis exploited by both plants and bacteria provides essential energy and chemicals for sustaining life. A photosynthetic system often comprises antenna complexes (ACs) that absorb incident sunlight and deliver the molecular excited state energy to a central reaction center (RC) that converts the energy to charge. Numerous efforts have been made to mimic natural photosynthesis using organic materials. However, short-range energy transport due to material disorder has hindered their success. Here, we demonstrate a photodetector that mimics this natural architecture. It employs an AC that exploits exceptionally long-range ( ∼ 100 µ m ) Bloch surface wave polariton propagation that directs the excited states to an organic heterojunction detector serving as the RC. Exciton–polaritons are largely immune to localization due to the partial photonic character of the polariton, which consequently transports energy over extraordinary distances from its point of origin. Exciton–polaritons are edge-coupled into an RC that harvests excitation energy by dissociation into an electron and hole. This device relies on polariton-to-charge conversion combined with long-range energy transport for the direct detection of excited states in organic semiconductors. Our work paves the way for the realization of large-scale artificial photosynthetic systems comprising integrated organic photonic and optoelectronic devices with efficient energy transport and harvesting under ambient conditions.