ZnO nanorod arrays with controllable lengths have been prepared on Cu(In,Ga)Se-2 solar cells by using electrodeposition. The optical qualities were improved by decreasing surface/volume ratio. A decrease of global weighted reflectance of the solar cell from 6.76% to 2.06-3.43% was demonstrated with ZnO nanorods as antireflective coatings. The antireflective effects were optimized by varying the structure characterizations of nanorods to match the refractive index profile that provides the most effective reduction of reflection. By enhancing the growth rate with an increase of NH4NO3 concentration in the electrolyte, the ZnO nanorods with the optimal antireflective effect can be fabricated more efficiently. (C) 2015 Elsevier B.V. All rights reserved.