Electrodeposition of p-type CuSCN thin films by a new aqueous electrolyte with triethanolamine chelation

A stable aqueous electrolyte solution containing Cu2+ and SCN- was prepared by adding triethanolamine (TEA, N(CH2CH2OH)(3)) to chelate with Cu(II) cations. The electrolyte solutions were basic, with pH values in the range of 8.5-9, and could be used in the electrodeposition of CuSCN as a hole-conducting layer on a ZnO substrate and as an electron-conducting layer for nanocrystal photovoltaic cells because it could prevent the ZnO layer from acidic etching. CuSCN films were potentiostatically deposited on indium tin oxide glass substrates through the aqueous solutions, and the deposition potential for the sole CuSCN phase layer was determined by a linear sweep voltammetry measurement. The influence of applied potentials, electrolyte components, and deposition temperatures on the stoichiometry, phase, and particle morphology of the CuSCN films was investigated by X-ray photoelectron spectra, X-ray diffraction, and a field-emission scanning electron microscope. The results showed that the morphology of the dense CuSCN films was trigonal pyramid and the stoichiometric portions of SCN/Cu were excess of SCN. The current-voltage (I-V) characteristic of the junction between electrodeposited CuSCN and ZnO nanostructured layer displayed p-type semiconductor characteristics of CuSCN. The transmittance measurements detected high transmittance (>= 87%) in the visible wavelength range, and the direct transition band gap calculated was 3.88 eV.