Preparation And Performance Study Of Chalcogenide Battery Films By Electrodeposition

With the decrease of traditional fossil energy, solar energy as a clean, safe and renewable energy has gradually attracted much attention. Photovoltaic power generation is one of the most important developing directions in the field of research on utilization of solar energy. In recent years CuS, Cu2O, CuInSe2 and the buffer layer material ZnS thin films have been become the hotspot and emphasis on the research of solar cell materials for their characteristics. The characteristics of CuS, Cu2O and CuInSe2 thin films are high optical absorption coefficient, those band gap width matched with the solar absorption spectrum, high efficiency and good stability. The characteristics of ZnS material are environmental protection and non-toxic. Thermoelectric generators and materials have been the focuses of research due to the requirements of environmental protection and energy crisis. Thermoelectric material is a kind of semiconductor materials for energy conversion and it is widely applied in the thermoe-lectric power generation and refrigeration at present.In this paper, the electrochemical performance of bath was tested by electrochemical workstation with stannic oxide conductive glass or copper as the basement. Photoelectric materials and thermoelectric materials have been prepared by crystal potentiostat and the materials include copper sulfide, zinc sulfide, copper indium selenide, cuprous oxide and bismuth telluride. The prepared thin films have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and four probe tester.(1) The factors including species of complexing agent, sulfur source and ratios of copper to sulfur ion, which influence the electrochemical performance of the prepared CuS plating solution, have been studied and discussed. Experimental results show that complexation is the best effect of sodium citrate, the followed is sodium gluconate, the worst is ethylene diamine tetraacetic acid (EDTA). The well-crystallized target product copper sulfide film can be deposited at -1.2V.(2) The factors which influence the preparation of ZnS films by electrodeposition have been studied and discussed. Experimental results show that the bath with sodium citrate is more stable. Although zinc sulfide prepared in all thin films prepared at -1.0～-1.6 V, the crystal plane of zinc sulfide film varied with the deposition potential.The films growth mainly in the directions of (100) prepared at -1.0V and oriented (101) crystal plane at -1.6V.(3)CuInSe2 thin films were prepared on the conductive SnO2 glass substrates. Experimental results indicate that the most appropriate deposition potential is -0.5V and composition of Cu-In-Se film will change with the variation of deposition potential in a larger range. The optimum concentration of complexing agentsodium citrate is 5 mmol/L and gully will appear in the film with the increase of the concentration of sodium citrate.(4) Cu2O films were prepared by electro-deposition using copper dichloride and sodium citrate as raw materials on the conductive SnO2 glass substrates. Experimental results show that when pH=1 Hydrogen evolution phenomena were quite serious with more intense ionic discharge, while the more stable reactions with pH=2 and small polarizability are conducive to formation of cuprous oxide film. When pH=1 and 2, only Cu2O peaks as product phase can be seen on glass substrates and the thin film crystal grow along the (110),(111),(200) crystal planes with elemental copper prepared in the film at the higher pH. The electrical properties of films vary widely in different pH solution, in which the resistivity of pH=2 film maximum, film minimum resistivity of pH=3 thin films.(5) Thermoelectric materials Bi2Te3 films were synthesized by electrodeposition using Bi2O3 and TeO2 as raw materials. when the deposition potential at -0.7 V, only elemental tellurium can be gotten in the product film while it increases up to -0.8 V Bi2Te3 film can be gotten with good crystallinity. With increase of the deposition, particle shedding phenomenon occurred.The film deposited with additives lactic acid added into the bath has higher film density and good crystallinity.