The Controlled Synthesis Of Semiconductor Nanocrystals And Nonlinear Optical Properties

Based on the principle of nanoparticle preparation, we designed a novel macromolecule template with controllable molecular structure as macro-reactors to prepare ZnS nanocrystals. The main contents of this dissertation consist of the following points:1. The research progress of semiconductor materials, synthesis method and characterization of zinc sulfide nanocrystallites are summarized.2. The natured decomposable Konac glucomannan (KGM) was selected as macromolecule material and modified by acetic anhydride, the modified KGM(AA-m-KGM) with the different degree of substitution(DS) were obtained. Using these modification natural decomposable m-KGM macromolecule as templates to prepare ZnS nanoparticles with controllable size and morphology.3. The effect of the different macromolecule templates and reactive conditions on the size% shape and properties of ZnS nanoparcticles were systematically studied. The structures of ZnS nanoparticles were analysed and characterized by ICP-ACEN IR^ FL> XRD and TEM. The optimal preparation technology was obtained.4. The optical limiting properties of ZnS nanocrystals were studied. The results revealed that they all possessed optical limiting effects to a laser with 40 ns pulses width at the wavelength of 532 run.