Preparation And Formation Mechanism Of Sb Doped CuS And CuSb Doped PbS Hierarchical Nanostructures

Copper sulfide?CuS?nanomaterial is a kind of typical p-type semiconductor compound,because of its low cost,high performance,high photothermal conversion rate,which is widely applied in many fields such as thermoelectric,lithium and photocatalyst.At present,the scientific research on the binary CuS compounds,from the synthesis of special micro/nano texture structures to the photoelectric,photothermal therapy and other applications,has become increasingly mature.However,it is difficult to obtain pure phase due to lacking of suitable and high reactive precursors,the research work of CuS-based ternary and quaternary nanomatrials with novel morphologies,is rarely reported so far.It is universally acknowledged that the crystal structure determines the nature of material,and the nature affects its application as well.Usually,the micro/nano texture structure of crystal plays a decisive role in macrocrystal shape,besides,the micro/nano texture structure ultimately affects its physcial and chemical properties.So the controlled synthesis of special micro/nano texture structures and crystal shape is a key factor to improve the performance of the materials.In this paper,in order to synthesize Cu₃SbS₄ ternary and Cu-Pb-Sb-S quaternary microcrystals,a mild,no template,cheap solvothermal synthesis method was developed to prepare multinary copper sulfide semiconductor nanomaterials by doping with different types,different concentrations of metal ions?Sb doped,Pb doped?in CuS hexagonal crystal lattice.To better understand and control the structures and investigate the growth mechanism of the chemical process at the molecular level and the nanometer scale,we put forward the chemical reaction route and crystal morphology evolution mechanism,that is,in-situ ion exchange self-sacrifice chemical transformation mechanism,form CuS parent template into ternary Cu₃SbS₄ and quaternary Cu-Pb-Sb-S target product.The specific research contents and conclusions are as follows:?1?Based on the synthesis of binary CuS materials,the experimental influencing factors of the synthesis of ternary Cu-Sb-S nanomaterials is systematically studied.The characterization results show that the prepared Cu₃SbS₄ ternary nanomaterials have a high yield and reproducibility.XRD and SEM results show that the obtained Cu₃SbS₄ is a 1.5 ?m-2 ?m hierarchical nano/micro spheres consisted of nanosheets with a thickness of 25 nm-30 nm.The optical band gap of the product is 0.47 eV by absorption spectroscopy.Time-dependent experiments revealed that by one-step solution method,a hierarchical structure of CuS was obtained as intermediate products at the earlier reaction step,And then,through in-situ ion exchange reaction,Sb ions diffused into theCuS lattice and replaced Cu ions,and formed Cu₃SbS₄ compound.In this way,a no residue,high purity product is obtained.In addition,it is found that chlorine existed,showing Cl doping Cu₃SbS₄ product were obtained in the sample,and the content of Cl element has important influence in the types of conductor.?2?On the basis of preparation of Cu₃SbS₄ ternary nanomaterials,Pb elements are added into the chemical reaction system.The effects of temperature,solvent and reaction time on the crystal shape and structure of the products are investigated by a series of detection and analysis techniques,including X-ray diffraction?XRD?,UV-vis spectra,Fourier transform infrared spectroscopy?FT-IR?,energy dispersive X-ray diffraction?EDX?.Cu-Pb-Sb-S quaternary compound exhibited a broken,hollow boat-like structure with a length of 5 ?m,a height of 80 nm and a thickness of 20 nm.It is very interesting that PbS is the main ingredient,Cu and Sb elements are doping elements with even distribution.EDX mapping results are well consistent with the XRD results.In addition,the effects of Cu,Sb and Pb on the chemical reaction system are systemmactily studied.It is concluded that there are synergistic effects on the three elements,and only with the proper molar ratio,specifically Pb:Sb:Cu= 12:1:14,can synthesize the hollow boat-like target quaternary product.This route provides a new perspective and new ideas for the study of photoelectric properties by controlling of other metal elements doped with CuS-based nanocrystals.It is suitable for the application of micro/nano devices,which may have potential application in optoelectronic and thermoelectric devices.