Photo-thermoelectric energy converter with black-Si absorber

Thermal to electrical energy conversation was increased by ~ 50% by dispersing 50-nm-diameter Au nanoparticles over the black-Si light harvesting surface at an optimized concentration of the Au-colloidal solution. The size of Au nanoparticles corresponds to the extinction maximum at the spectral location of the reflection dip of black-Si substrate. Black-Si with reflectivity of 1-2% over the entire visible spectrum 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.