17.3% efficient black silicon solar cell without dielectric antireflection coating

17.3% efficient black silicon (b-Si) solar cell without antireflection coating was achieved via tetramethylammonium hydroxide (TMAH) etching after the formation of the diffusion emitter. Large area (156 × 156 mm2) b-Si wafers were prepared by silver-nanoparticle-assisted etching on pyramid-structured silicon wafers. The modification of nanostructures of silicon surface by TMAH etching suppresses the surface recombination and Auger recombination at and near the emitter surface, and the effective minority carrier lifetime of the b-Si solar cells was improved from 10.7 μs to 20.8 μs. Although the average reflectance of the b-Si solar cell slightly increases from 2.38% to 2.71% via the process of TMAH etching, it is a small loss compared with the beneficial impact of the improvement of the carrier recombination lifetime. As a result, the internal quantum efficiency at short wavelength region was improved through the TMAH etch treatment, which was a main limiting factor for the efficiency of b-Si solar cells.