Low-toxic Solution-processed Copper-indium-selenium-based Thin Film And Its Photovoltaic Application

?-?-? chalcopyrite CuInSe₂ compounds,as the promising optical-absorption materials,have important position and broad prospects for development in the field of thin-film solar cells,due to their unique optical and electronic properties.The preparation of CuInSe₂ thin film by non-vacuum solution method is a kind of thin film deposition technology which has been developed rapidly in recent years,due to its low manufacturing cost,simple control of composition and stoichiometry,easy film forming and flexible,has aroused widespread concern in the field of research.At present,the hydrazine solution method as the first developed solution deposition process,has achieved considerable success in the film quality and photoelectric conversion efficiency.However,hydrazine is poisonous,flammable and explosive,and safe operation requirements are extremely high.Therefore,it is a hot research to find low toxicity solvent instead of hydrazine to prepare high quality films.In this paper,a novel,low toxicity thoil-amine solution mixed with mercaptoethanol and ethylenediamine was used to fabricate the CuInSe₂ precursor solution by dissolving Cu,In and Se powders precursors for the first time.The chalcopyrite CuInSe₂ films were successfully prepared by simple spin-coating and post-selenization processes.The effects of selenium vapor,Cu/In ratios,heat treatment times and temperatures on the phase,structure,morphology and optical properties of the films were investigated.The results showed that the pure phase CuInSe₂ films were obtained by using 40 mg Se powder as the selenium source,in an atmosphere pressure of 0.03 Mpa and at 550? for 30 min.Th ecomposition was poor-Cu,The crystallinity and compactness of the film were high,The average grain sizes were 960 nm,and the forbidden band width was 1.0 eV,It was suitable for the preparation of highly efficient CISe thin film solar cells.In addition,a low-toxicity thoil-amine solution mixed with ethanedithiol and ethylenediamine was used to prepared CuInS₂ precursor solution,with elemental S powder instead of Se powder.Through post-selenization processing,a dense and double large grain structure CuIn?S,Se?₂ thin films were successfully prepared.the films'density and band gap were improved by the doping of S elements.And the effects of heat treatment temperatures on the phase,structure and morphology of the films were investigated.A thin film solar cell with CISSe thin film as the absorptive layer was successfully fabricated,and 6.2%photoelectric conversion efficiency was obtained under AM1.5 standard illumination condition.