在无水无氧条件下通过热分解还原制备Co纳米微粒,利用Co_9S_8和ZnO晶格的相匹配性,通过层层自组装对Co表面进行修饰,得到Co/Co_9S_8/ZnO核壳结构纳米微球.采用XRD、TEM、SQUID、光致发光光谱(PL)等对产物进行了表征.通过调节反应参数制备出核壳结构的Co/Co_9S_8/ZnO复合纳米微球,平均粒径58.8nm,壳层厚度均匀,常温下显示铁磁性,矫顽力为18.7kA/m.PL表明,产物在380～390nm处的带边跃迁不明显,光致发光最强峰在468nm处,属氧缺陷发射峰,研究了影响产物形貌的主要因素.结果表明,以油酸(OLA)及三正辛基氧化磷(TOPO)为溶剂和表面活性剂,Zn(acac)_2温度为70℃、用量为1mmol,控制Co的硫化反应时间为5min,有利于核壳结构产物的形成.初步分析了Co/Co_9S_8/ZnO核壳结构纳米微球的形成机理.
Co/Co_9S_8/ZnO core-shell nanoshperes were successfully prepared via a thermal decomposition in the water and oxygen-free environmert. The lattice-match between Co_9S_8 and ZnO played a significant role on the layer-by-layer self-assembly of the core-shell nanospheres. The as-synthesized nanospheres were charac-terized by XRD, TEM, SQUID and Photoluminescence Spectra. By controlling the reaction parameters, the core-shell nanostructure with uniform size of about 60 nm and shell thickness of 13.6nm was obtained. The effects on the shape control of the product were further investigated, and a proper formation mechanism of the Co/Co_9S_8/ZnO core-shell nanostructures was presumed. The results show that the favorable procedure to ob-tain the core-shell nanostructure shape is as follows, the reactants of OLA as solution and TOPO as surfac-tant, and the optimal temperature and quantity for precursor Zn (acac)_2 is 70℃ and 1 mmol, respectively. In additon, the sulfidation reaction time for Co is 5 min. The products show ferromagnetism at room temperature with a coercive force of 18.7kA/m. In the photoluminescence measurement, the strongest peak at 460nm which is attributed to oxygen defects can be obtained, while the band edge transitions of ZnO between 380nm and 390nm can hardly be observed.
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