Structure-controlled ZnO/Cu2O inorganic solar cells by electrodeposition

We report one-dimensional (1D)- nanostructured ZnO/Cu₂O all-oxide inorganic thin film solar cells prepared by electrodeposition from aqueous solutions without thermal treatments and vacuum techniques. The structural morphology of n-type ZnO and p-type Cu₂O is customized by adjusting electrodeposition conditions to fit each other. Vertically aligned ZnO nanopillar arrays are obtained densely on transparent conductive oxide glass (TCO). For the Cu₂O electrodeposition, its crystallographic orientation and grain size are controlled so as to match with the ZnO by adjusting solution pH and applied current density. Characterization is performed by X-ray diffraction and field-emission scanning electron microscopy. The simple all-oxide solar cell composed of TCO/ZnO-nanopillar/Cu₂O/Au exhibits a higher conversion efficiency than that using a planer-type ZnO film.