Highly efficient industrial large-area black silicon solar cells achieved by surface nanostructured modification

SEM images of silicon with nanotextured surface and additionally subjected to TMAH modification for 30s. •We achieved a 19.03% efficient large area black silicon solar cell.•This efficiency is 0.18% higher than that of standard silicon solar cells with pyramidal surfaces.•The local surface recombination velocity is successfully suppressed to 112cm/s.•It results in an increase in the IQE of black silicon solar cells at short wavelength region. Traditional black silicon solar cells show relatively low efficiencies due to the high surface recombination occurring at the front surfaces. In this paper, we present a surface modification process to suppress surface recombination and fabricate highly efficient industrial black silicon solar cells. The Ag-nanoparticle-assisted etching is applied to realize front surface nanostructures on silicon wafers in order to reduce the surface reflectance. Through a further tetramethylammonium hydroxide (TMAH) treatment, the carrier recombination at and near the surface is greatly suppressed, due to a lower surface dopant concentration after the surface modification. This modified surface presents a low reflectivity in a range of 350–1100nm. Large-area solar cells with an average conversion efficiency of 19.03% are achieved by using the TMAH treatment of 30s. This efficiency is 0.18% higher than that of standard silicon solar cells with pyramidal surfaces, and also a remarkable improvement compared with black silicon solar cells without TMAH modifications.