Facile omnidirectional black silicon based on porous and nonporous silicon nanowires for energy applications

High reflection losses and low photon absorption combined with high velocity large area surface recombination are the main obstacles for boosting the efficiency of solar cell. We report a simple large-scale one step catalytic room temperature fabrication approach of black silicon (B-Si) in an aqueous solution of HF and AgNO
₃
. B-Si based on porous and nonporous Silicon nanowires (SiNWs) shows a superior optical properties with low reflectance <;0.1% and unprecedented absorption > 99.9% in the solar irradiance peak (wavelength range 400 to 800 nm). The black silicon reflects <;2% at different incident angles up to ±60°. The black silicon consists of nonporous and porous SiNWs of tuned filing ratio from 130 to 750 nm, matching the wavelength of the incident light for improved light trapping inside the nanostructure.