Abstract Tapered aluminum-doped vertical zinc oxide nanorod arrays have been prepared by using simple electrodeposition at 75 °C from an aqueous solution of zinc nitrate and aluminum nitrate. Two substrates were used, i.e., copper indium gallium (di)selenide solar cells and a solar thermal absorber. The resulting nanorod arrays were of high optical quality, indicting their applicability as a light coupling layer via a moth-eye effect by means of the subwavelength structure. The weighted global reflectance of the substrates’ surface is decreased after coating it with the light coupling layer. The coating layer boosts the solar cells’ short-circuit current without an obvious effect on their open-circuit voltage and changes the solar thermal absorber layer to a novel solar selective surface. The studies show that the aluminum-doped vertical zinc oxide nanorod arrays are an excellent light coupling element for both solar cell antireflective coating and solar thermal selective surfaces.