Preparation And Characterization Of CuinS₂Thin Film Solar Cells

As clean and new energy, solar energy has been praised the Father of thePeople, and has very broad development prospect. In all photovoltaic devices,CuInS₂is direct band gap semiconductor material, and the light absorptioncoefficient is large, it is suitable for thin film solar cells absorbing layer. In thepaper, potentiostatic electrodeposition method was elected to prepare the CuInS₂thin film, because of the large area deposition in the room temperature.One step electrodeposition method was adopted to deposit p-CuInS₂thinfilm on the FTO glass substrate; the electrolyte was a sulfate aqueous solutionsystem which contained copper sulfate, indium sulfate, sodium thiosulfate andsodium citrate, and the FTO glass was cathode, and the orthogonal experiment ofelectrodepositing was used to optimize and obtain the ideal CuInS₂thin film.Chemical bath deposition method was adopted to deposit n-In2S3thin film.In2S3is a compound semiconductor belonging to III-VI family, and is availablefor advanced n type buffer material for the solar cells due to its excellent materialproperties, such as suitable band gap energy of2.0-2.45eV, and is not providedwith toxicity. And the elements of In2S3are almost the same with the elements ofCuInS₂, so there is no interface state in favor of advancing lattice matching anddecreasing recombination among the photo-carriers. Also, we tested the solar cellmodules to obtain the corresponding Voc, Iscinformations.Basing on the above experiments, we analyzed the CuInS₂and In2S3thinfilms, including that scanning electron microscope （SEM） and atomic forcemicroscope （AFM） analysis for the thin film surface morphology; X-raydiffraction （XRD） and X-ray photoelectron spectroscopy （XPS） analysis for thecomposition of membrane; linear scan and absorption spectrum test analysis for thin film photovoltaic performance; cold and hot probe experiment analysis forthin film semiconductor type.Also, basing on the first principle density function theory, the Reflex modulewas used to confirm chalcopyrite model for the experiments, and the CASTEPand DMol3modules were used to simulate the band structure and the statedensity of CuInS₂after the geometry optimization, using Generalized GradientApproximation （GGA） to accurate the results, the simulation results of the bandgap were1.40eV, which were almost the same with the results of the experime-nts.