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

Research highlights: → A simple CBD method used for preparation of Cu2O nanorods on different substrates. → Nanorod array density and size is dependent on both substrates and CTAB concentration. → Cu2O nanorods on Ti foil can absorb the most visible light. → Cu2O nanorods on Cu foil demonstrate best and most stable photoelectricchemical property. - Abstract: 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.