Cu2O nanorod thin films prepared by CBD method with CTAB: Substrate effect,deposition mechanism and photoelectrochemical properties

Cuprous oxide (Cu₂O) films with different nanostructures are deposited on different substrates of fluorine-doped SnO₂ (FTO) glass, Cu and Ti foil respectively by using chemical bath deposition (CBD) technique with the presence of cetyltrimethylammonium bromide (CTAB). The samples are characterized by X-ray diffractmeter, scanning electron microscopy and UV–vis diffuse reflectance spectroscopy. The results show that the prepared Cu₂O films are composed of nanorod arrays when there is CTAB in reaction system. Without CTAB, Cu₂O films with nanospheres are formed. The concentration of CTAB is crucial for the controllable synthesis of nanorod structured Cu₂O films with different length to diameter ratio and nanorod array density is dependent on both substrates and CTAB. A possible mechanism for the formation of Cu₂O nanorods is discussed. Additionally, the UV–vis absorption property for Cu₂O nanorods is much better than that for nanospheres. The photovoltage produced under visible light for Cu₂O nanorod films is higher than that for the nanospheres. Although Cu₂O nanorods on Ti foil can absorb the most visible light, those on Cu foil demonstrate better and more stable photoelectrochemical property than those on any other substrates. This study may be extremely useful for Cu₂O based device with nanostructures.