Cd-Zn-S Compound Film Deposited By CBD Method Performance Study

In the past few decades,cadmium sulfide(CdS)has been widely used as a buffer layer for solar photovoltaic modules.However,due to the small band gap(2.42ev)of CdS,the photoelectric conversion efficiency of the battery is restricted,and cadmium is toxic.In order to improve the performance of buffer layer,zinc sulfide(3.75ev)with large band gap was proposed as an alternative material.However,it is found that the lattice matching between ZnS and CIGS thin film solar cells is poor,which seriously affects the efficiency of ZnS as a buffer layer.Therefore,CdZnS semiconductor thin film materials emerged.On the one hand,the content of cadmium in the CdZnS thin film is reduced.On the other hand,by controlling the content of zinc in the CdZnS thin film,the optical and electrical properties of the thin film can be adjusted,thus improving the efficiency of solar cells.In this paper,CdZnS thin films were prepared by chemical water bath(CBD),using cadmium sulfate(CdSO₄),zinc sulfate(ZnSO₄),thiourea SC(NH₂)₂ as raw materials,ammonia sulfate(NH₄)₂SO₄ as buffer,ammonia water as complexing agent and acid-base balance regulator.Environmental field emission scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),X-ray diffraction(XRD),UV-vis and near-infrared spectrophotometer were used to test and characterize the properties of the films.The main conclusions are as follows:1.The effect of the concentration of complexing agent(ammonia water)on the properties of CdZnS film was studied by the CBD system experiment.That is to say,a certain concentration of ammonia water solution can effectively inhibit the formation of precipitates in the reaction solution,thus promoting the formation of complexes in the solution.With the increase of ammonia water concentration,the film gradually thickens,the band gap first increases and then decreases,and the surface morphology first improves When the ammonia concentration is 0.4m,the film performance is relatively best.A SCI paper has been published as the first author on this topic,which is now included and retrievable.The influences of buffer(ammonia sulfate),cadmium sulfate,zinc sulfate and thiourea on the properties of CdZnS films were studied;2.The function relationship between X=Zn/(Zn+Cd)value and band gap(Eg)of the film is obtained by function fitting.The functional relationship is:Eg=2.42+0.96x+0.37x².In general,the research on CdZnS films as buffer layers for CIGS solar cells is still scarce both at home and abroad,so this paper has important significance for the research of CdZnS films.