Plasmonic materials for energy: From physics to applications

Physical mechanisms unique to plasmonic materials, which can be exploited for the existing and emerging applications of plasmonics for renewable energy technologies, are reviewed. The hybrid nature of surface plasmon (SP) modes – propagating surface plasmon polaritons (SPPs) and localized surface plasmons (LSPs) – as collective photon–electron oscillations makes them attractive candidates for energy applications. A high density of optical states in the vicinity of plasmonic structures enhances light absorption and emission, enables localized heating, and drives near-field heat exchange between hot and cold surfaces. SP modes channel the energy of absorbed photons directly to the free electrons, and the generated hot electrons can be utilized in thermoelectric, photovoltaic and photo-catalytic platforms. The advantages and disadvantages of using plasmonics over conventional technologies for solar energy and waste heat harvesting are discussed, and areas where plasmonics is expected to lead to performance improvements not achievable by other methods are identified.