Solvothermal Synthesis Of ZnS And Doped Nanocrystallines

ZnS nanocrystals (NCs), as a typical II-VI semiconductor, are non-toxic and have the size-tunable fluorescences, promising to find applications in biolabels and photoelectronic devices. Due to this, ZnS NCs has become focused systems in semiconductor NCs. The synthesis of monodispersed and shape-controllable ZnS NCs and study of their self-assembly as well as fluorescence properties are significant to their applications.By solvothermal reactions, we synthesized monodispersed ZnS nanocrystallines from stearate zinc and stearate acid, and the ZnS nanocrystallines exhibited self-assembly behavior in ordered structures. As a further step to improve photoluminescence (PL) of ZnS NCs, we studied dopping of Mn and Cu into ZnS NCs and their PL properties.The variation of the reaction conditions showed a wide range of synthesis window for the formation of hollow NCs which formed in the range of the mole ratio [S]/[Zn] of 6～12, temperature of 250～320°C and the isothermal time of 0.5～2 h. The replace of different Zn-sources, solvent and ligand did not produce hollow NCs but dense ZnS NCs, indicating the critical control of the NC growth by the chemistry of the Zn-source, ligand and the solvent. The hollow NCs emitted violet photo-luminescence under ultraviolet excitation at room temperatures.To enhance PL of the ZnS NCs, NCs of Mn/Cu-doped ZnS were synthesised from the solvothermal reactions of stearate zinc and magnesium acetate in ODE ligand with oleic acid as a solvent. The Mn:ZnS NCs thus prepared have sizes of 10 nm and exhibited excellent self-assembly behavior. The copper-doped ZnS NCs have sizes as small as 2 nm which displayed PL peak at 518 nm.