Plasmonic photo-thermoelectric energy converter with black-Si absorber

Thermal to electrical energy conversation by Seebeck element was enhanced by up to ∼ 50% by dispersing 50 nm diameter Au nanoparticles over the black-Si light harvesting surface at an optimized concentration. Size of Au nanoparticles is the defining factor for the spectral position of the extinction maximum at which the cumulative absorption of black-Si (without nanoparticles) can be augmented resulting in an increase of voltage produced by a Seebeck element. Black-Si with reflectivity of 1-2% over the entire visible spectral range is a promising material for extending the operational range of solar and thermal energy converters into longer wavelength regions. Numerical simulations reveal efficient localization of light energy absorption inside black-Si.