Research On Depositing CuInSe₂ On Polyimide Thin Films

Global energy shortage and environmental issues have become increasingly prominent.Solar energy is inexhaustible and clean energy,thus it is effective solution to these problem.Meanwhile,copper indium diselenide?Cu In Se₂,CIS?is considered as the most promising materials for the application of the thin film solar cell,owing to its ability to adjust optical band gap,high optical absorption coefficient?6×10⁵/cm?,strong resistance to radiation ability and good stability.In the thesis,eletrodeposition has attracted much attention because of its low cost,low temperature preparation,large area and continuous processing.In this paper,we have deposited Cu In Se₂ films by one step electrodeposition method on polyimide which has electroless nickel plating.The experiment is composed of electroless nickel plating on the polyimide and electroplating Cu In Se₂ films.First,PI films is pretreated by degreasing,roughening and activating,and then we use orthogonal experiment and single factor analysis method to optimize the experiment,and obtain the best electroless nickel plating technology.Finally,we choose the solution including Cu SO₄,In₂?SO₄?₃,Se O₂and sodium citrate as electrolyte,metallized polyimide films as cathode,and electrodeposit CIS thin films by the constant potential method.In addition,we use the orthogonal experiment and single factor analysis to optimize the experiment,and obtain the optimum electrodeposited CIS technology.Based on the above experiments,we use SEM and AFM to determine surface morphology of the thin film which has deposited nickel and CIS,EDS and ICP-AES are respectively used to analyzed the contents of the thin film which has deposited nickel and CIS,XRD and XPS are used to analyze the component and the phase structure,tensile test is used to analyze bonding strength of the nickel and PI thin films.At the same time,we analyze the photoelectric effect of the film by linear sweep voltammetry and absorption spectrum,use Thermo-Needles experiment to analyze electric conduction type of the CIS thin films.The results show that electoless nickel coating is flat and compact,it is composed of amorphous Ni-P alloy,and the adhesive strength of the nickel coating and PI thin films was strong.The surface of the CIS films is also basically flat,the structure is compact,and the crystallinity is good.The band gap of CIS was 1.43 eV,and the absorbance and photoelectric effect is eximious.