Synthesis of ZnO/CuO composite coaxial nanoarrays by combined hydrothermal–solvothermal method and potential for solar cells

CuO nanoparticles (NPs) sensitized ZnO nanorod composite coaxial nanoarrays were successfully prepared by a combined hydrothermal−solvothermal method. Scanning electron microscopy images show that the number of CuO-NPs on ZnO nanorod surface can be controlled by the reaction time. Synthesis mechanism of ZnO/CuO nanoarray was studied in this work. The Cu ²⁺ ions in solution would be captured by Zn vacancy on ZnO nanorod surface, and then combined with hydroxy groups in solution to formation Cu(OH) ₂ , providing the initial nucleation for surface growth of CuO-NPs. Moreover, the optical absorption properties of ZnO/CuO nanoarray and energy band analysis suggest that CuO can both serve as the supplementary absorption material and electron acceptor for conjugate polymer in polymer–inorganic hybrid solar cells, or might become the light-harvesting material in dye-sensitized solar cells.