Synthesis Of Cu-In-Se（S）sub-binary Compounds And Their Application In Preparation Of Ternary CuInSe₂ Based Thin Films By Solution Method

Due to the characteristics of tunable band gap and high visible light absorption coefficient of CuInSe₂ based semiconductor,the efficiency of CuInSe₂ based solar cells can reach 22.8%.However,the high-quality single chalcopyrite phase CuInSe₂based light absorption layer is difficult to prepare in large area at low cost,which restricts the further development of solar cells devices.In view of the above problems,based on the liquid-phase promoted densification and small size effect,the Cu-In-Se（S）sub binary compounds materials of micro/nanostructure were prepared by adjusting the experimental conditions with the hot injection method.And then the binary nanoparticles and ion precursors were deposited by dip-coating to obtain the preformed layer for sintering.The high-quality CuInSe₂ film was prepared.And the process of Y-substituted In for forming chalcopyrite phase Cu Y（SSe）₂ was investigated by the same process.The specific contents are as follows.In the synthesis of CuInSe₂ sub-binary compounds,the preparation of Cu Se₂,In₂Se₃ and Cu S materials of micro/nanostructure were studied by hot injection method using triethylene glycol as solvent and polyvinylpyrrolidone as dispersant.By means of XRD,SEM,TEM,EDS and other test methods,the effects of reaction conditions such as cation supply mode,injection and reflux temperature,and different reducing agents on the phase composition and morphology of the products were investigated.The single-pyrite metastable Cu Se₂ was obtained by refluxing at220°C for 30 min with the aid of weakly reducing glucose.The In precursor solution was injected dropwise,then nearly amorphous In₂Se₃ and In₂Se₃nanocrystals were synthesized at 250°C and 270°C,respectively.The hexagonal copper sulfide nanocrystals were synthesized by injecting Cu precursor solution drop by drop at 190℃ and refluxing for 30 minutes.The above research lays a foundation for the preparation of ternary CuInSe₂ based films.As for the preparation of ternary CuInSe₂ based optical absorption thin films,homogeneous and stable inks can be obtained by mixing binary amorphous In₂Se₃nanosheets and Cu amine complex as In-Se precursor and Cu precursor,respectively.The single chalcopyrite CuInSe₂ was obtained at 550℃ by selenium sintering the preformed film deposited by mixed ink.The remelting decomposition of the Cu-Se compounds with low melting can provide Se liquid phase to promote ion diffusion and densification sintering in the heat treatment process.The film has a flat surface and excellent electrical properties with an electrical resistivity of 3.19Ω·cm,carrier concentration of 2.63×10¹⁷ cm^-3,mobility of 7.43 cm²V^-1S^-1,which provide a material basis for the preparation of high-performance cell devices.In addition,the Cu S nanosheets and YCl₃ solution as the precursors were deposited successively by dip-coating to obtain the preformed film.After selenidation heat treatment above500°C,the film with chalcopyrite phase Cu Y（SSe）₂ as the main crystal phase was prepared.We studied the formation and transformation of intermediate phase(Cu_2-x（SSe）,Y₂Se₃)into Cu Y（SSe）₂,which provides the experimental basis for the preparation of Cu Y（SSe）₂ material.