A novel method to prepare ZnO/Ni multilayer thin film used in back electrode for solar cell

• The ZnO/Ni back electrode was prepared by electroless plating and sol–gel methods.
• The growth mode changed from the island growth to the layer-by-layer growth.
• The light trapping structure was formed on the surface of the back electrode.
• The lowest transmittance of about 1.06% was obtained.

In order to improve the conversion efficiency of the solar cell, the ZnO/Ni multilayer thin film used in back electrode was prepared through the electroless plating and sol–gel methods. The morphology, structure and resistivity of the electroless nickel coating were measured by scanning electron microscopy, X-ray diffraction, and four-point probe resistivity tester, respectively. It was found that the nickel coating presented crystalline structure with the lowest resistivity of 4.33×10−5 Ω cm. The effect of the ZnO sol concentration, annealing temperature and the number of the spin-coating layers on the crystal structure, film morphology and photoelectric performance were also studied. The light trapping structure was found on the surface of ZnO layer when the sol concentration, annealing temperature and the number of the spin-coating layers were 0.75 mol/L, 300 °C and 4, respectively. The average transmittance in the visible light range (390–780 nm) was about 1.06% by visible spectrophotometer. The ZnO/Ni multilayer film could be used in back electrode for solar cell and would improve the properties of the solar cell.