CIGS Microporous Membrane Preparation Of Electrodeposition And The Research Of Performance

The energy problem is becoming more and more serious. There are many peoplewho begin to pay attention to the development and utilization of solar energy. Thesolar cell is a way to use the solar energy effectively. CIGS film is paid moreattention as the absorption layer of solar cells. The purpose of this paper is toresearch membrane electrodeposition process in ionic liquids and its performance.The micropore structure can increase the film’s superficial area to improve thephotoelectric conversion efficiency of solar cells.To keep it simple in this article, electrodeposition of copper or nickel was toseek the method for preparation of metal microporous membrane by using templateor template-free. Finally, the good method of preparation of microporous membranewas chosen.Template-free includes control the current density and etching substrate. Theprinciple of two methods is almost identical. They both utilize the prior reduction ofmetal ions in a certain position of the substrate. However, large current densitycould make the ionic liquid resolve and the concavity and convexity of etchingsubstrate surface by ferric chloride is poor. Microporous structure is not ideal.The method of template includes microporous membrane, insulative coating andself-assembly polystyrene microsphere(PS). Microporous membrane couldn’tcombine very well with substrate. There was a bubble between microporousmembrane and substrate and the structure of the microporous membrane is reticular.It is harmful for preparation of metal microporous membrane. Insulative coating islayer of varnish. The methods of hexavalent chromium, doped alumina nano powderand spraying varnish couldn’t get uniforim micropores. The distribution of PS isuniform on the substrate surface. PS has good insulation and adsorption. Coatingscan only grow along the gaps of PS. Ultimately, microporous structure of the thinfilm was prepared.Studies have shown that the method of self-assembly polystyrene microspherecould get microporous membrane of metal. This article researched the influence ofthe concentration of PS, self-assembled conditions, the time of deposition, substrateand the deposition potential to thin film morphology of CIGS. When PS was diluted,its distribution became nonuniform. Self-assembled conditions could influence thedistribution of PS. The arrangement was orderly when the temperature was50℃inthe vacuum. Microporous structure of CIGS was homogeneous. As the extension ofdeposition time, micropore would gradually disappear. Microporous structures of CIGS had big difference in different substrates and ionic liquids. Thin filmmorphology obtained in1-butyl3-methyl imidazole fluoroform sulfonate was better.The performance of the CIGS microporous membrane were studied. Thesuperficial area of CIGS microporous membrane used PS template has improvedgreatly. The superficial areas of CIGS microporous membrane are259.5cm~2and284.5cm~2when the deposition time is15minutes and30minutes, respectively. Thesuperficial area of film on the copper was much larger than it on the nickel. Theband gap of CIGS microporous membrane wass about1.5eV. Whenever annealed ornot, the film on the nickel is n-type semiconductor through measuring the hallcoefficient. And the film on the ITO is n-type semiconductor before annealed.However, the film could disappear after annealed. The reason is that the adhesion isvery poor between ITO and CIGS film. It may be improved by a layer ofmolybdenum should be sputtered on the ITO. The film used PS template on thecopper is n-type semiconductor. It becomes p-type semiconductor after annealed inAr atmosphere for1h. Its carrier concentration also increased.