| With the continuous development of society,the demand for energy of the human race was increasing.Facing the two major issues of energy crisis and environmental pollution,renewable and clean energy should be developed urgently.As a renewable energy technology that utilized solar energy to generate electricity,photovoltaic power generation was expected to solve the problems of energy shortage and environmental pollutions.But the cost of photovoltaic was generally too high,it was imminent to explore low-cost preparation process of solar cells.Specially,the unique structure of 3d electronic shell of chalcogenide films for transition metal making them widely used in the field of thin film solar cells.In this paper,we developed a facile molecular precursor solution method to fabricate CdS,Cu9S5 and ZnS thin films.Meanwhile,the optimal preparation technologies and the applications in solar cells were studied.First of all,the CdS films with controllable thickness were prepared by molecular precursor solution method using Cd?CH3COO?2·2H2O,TU and DMF as cadmium source,sulfur source and solvent,respectively.Then,the concentration of the precursor solution was adjusted by quantifying the raw material while altering the amount of solvent.The CdS precursor thin film was obtained by spin coating.After subsequent hot plate processing at 200?,CdS film with high coverage and good uniformity was prepared successfully.At last,the CdS film was used as buffer layer to fabricate CIGS solar cell.It was found that the photoelectric conversion efficiency?PCE?of CIGS device with a CdS layer of 25 nm was 0.88%,which was higher than that of 75 nm.Secondly,the Cu9S5 film with the characteristics of p-type semiconductor were prepared by molecular precursor solution method using CuCl2,TAA and DMF as copper source,sulfur source and solvent,respectively.It was found that Cu9S5 film can be fabricated only when the molar ratio of Cu/S was 1:4.The aging time of the precursor solution had a great influence on the structure and coverage of Cu9S5 thin films.With the increase of aging time,the surface of Cu9S5 films underwent the transformation of grain,flower and flake in morphology,accompanied by increase in coverage.Finally,the most suitable aging time was 7 days.At the same time,the thermal processing can also influence the structure and coverage of Cu9S5 film.Great deal of organic matter was remained on the surface in a thermal processing of 200?.When the temperature of thermal processing rose to 250?,the organic matter can volatilize completely and the Cu9S5 film accumulated with flakes was formed.The as-prepared Cu9S5film formed a p-n junction with the MAPbI3 layer,showing the characteristics of p-type semiconductor.Finally,the ZnS films with high coverage and density were prepared by molecular precursor solution method using Zn?CH3COO?2·2H2O,TU and DMF as zinc source,sulfur source and solvent,respectively.Since both of two zinc sources of Zn?CH3COO?2·2H2O and Zn?NO3?2·6H2O can be dissolved in DMF,the precursor solution was synthesized with two kinds of zinc source and sulfur source.It can be concluded that the most favorable zinc source and sulfur source for the formation of ZnS film were Zn?CH3COO?2·2H2O and TU.However,the content of sulfur element and band gap were always less than the standard value.Thus,the process needs further optimization. |
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