Plasmonic nanostructures in solar energy conversion

Photocatalysis and photovoltaics are two major approaches sharing similar processes (including light absorption, and charge generation and separation) for solar energy conversion with semiconductors. Various strategies have been proposed to improve the efficiency of solar energy conversion due to limited light absorption and rapid charge recombination in semiconductors. Integrating semiconductors with plasmonic nanostructures has been proven as an effective way to greatly enhance the performance in photocatalysis and photovoltaic devices. This review outlines the fundamental mechanisms, including hot electron injection, local electromagnetic field enhancement and resonant energy transfer, which are responsible for both plasmonics-enhanced photocatalysis and photovoltaics. Furthermore, we review some recent progress in practical applications such as photocatalytic water splitting, artificial photosynthesis, photodegradation of organic pollutants and solar cells integrated with plasmonic nanostructures. In specific cases, the possible working mechanisms for the enhancement of photocatalytic or photovoltaic performance by plasmonics are clarified together with materials design. Finally, the existing challenges and future prospects for the utilization of plasmonics in solar energy conversion are discussed.