Abstract
ZnO nanostructures as anti-reflective coatings were synthesized by using hydrothermal technique for a sulfurization-free Cu 2 ZnSnS 4 absorber prepared by co-sputtering deposition. By controlling the morphology of solution-grown ZnO nanostructures, the average reflectance of the Cu 2 ZnSnS 4 solar cell with branched ZnO nanorods decreased from 7.6% to 1.12%, and the energy conversion efficiency promoted by 10.4% from the initial value of 4.8% to 5.3%. The efficiency improvement was well studied with the effects of the gradually increased refractive index between the air and the top electrode of Cu 2 ZnSnS 4 solar device, due to the presence of the ZnO nanostructure. © 2013 AIP Publishing LLC.