Optical Resonator Enhanced Photovoltaics and Photocatalysis: Fundamental and Recent Progress

Solar light is recognized as one of the most valuable sustainable energy sources of the future. Finding solutions to enhance energy-conversion efficiency is of paramount significance for realizing more efficient photovoltaic and photocatalytic devices. Remarkable development in chemical and physical strategies has been explored to increase the optical-absorption coefficients, extend the spectral range, and optimize the light-harvesting and conversion efficiency. Optical resonators, which play a ubiquitous role in modern optics, possess the unique ability to provide strong optical confinement and enormous light-matter interactions. Such features have attracted tremendous attention in photoelectric enhancement and applications in photovoltaic, photocatalysis, and even light-emitting devices recently. This review presents theoretical as well as experimental progress on enhanced photovoltaic and photocatalysis by exploiting optical resonators. Fundamentals of various optical cavities are discussed according to confinement and photoelectric enhancing mechanism, including Fabry-Perot, whispering gallery mode, photonic crystal, plasmonics, and hybrid cavities. Finally, the application prospects of cavity-enhanced photoelectric effect, including strong coupling, cavity design, and challenges are discussed. It is envisioned that the successful implementation of optical resonators in photoenergy applications may open a promising avenue for a broad spectrum of light-energy-conversion technologies.