Hydro/Solvothermal Synthesis And Characterization Of Bi₂E₃（E=S,Se）Nanomaterials

Bismuth sulfide (Bi2S3) and bismuth selenide (Bi2Se3) are binary chalcogenide inorganic semiconductor materials with a direct band gap. For they are steady and environmentally fridendly and have good photoelectric conversion, Bi2S3and Bi2Se3have wide application prospect in photovoltaic conversion, thermoelectric device and photocatalysiss. In this thesis, Bi2S3and Bi2Se3with different sutuctures including nanorods、nanosheets and nanoscale arrays are synthesized by using hydrothermal method and solvothermal method at a relative low temperature. By changing the experimental conditions, such as reactant types, the molar ratios of reactants, solvents, reaction temperature, heating time and ligands, we can obtain Bi2S3and Bi2Se3nanomaterials with different morphologies and sizes.In part one,we have successfully synthesized Bi2S3nanorod arrays with different length-diameter ratio by using bismuth nitrate (Bi(NO3)3·5H2O) and mercaptosuccinic acid (MSA) as precursors through hydrothermal method. The crystal forms, compositions and morphologies of products are analyzed by XRD, SEM and TEM. Furthermore,we studied the influences of temperature, reactant mole ratios, mixed solvent ratios of distilled water and N,N-dimethylformamide on the morphologies of products.In part two, we have explored the synthesis process of Bi2Se3nanosheet and nanosheet arrays in distilled water, ethylene glycol (EG)、N,N-dimethylformamide (DMF) by using Bi(NO3)3·5H2O and selenourea(CSe(NH2)2) as reactants. We also analyzed the influences of heating condition, reacting time, reactant mole ratio and ligand types on morphologies of products.