空心CdS纳米晶的合成及发光性能研究

Synthesis and photoluminescence performance of hollow CdS nanocrystals

以氯化镉和硫化钠为原料,在水相体系中合成CdS纳米晶,通过透射电子显微镜观察发现,在100℃下合成的CdS纳米晶具有空心结构,粒径为20～30nm,且壁厚均匀,约为3～5nm;在70℃下合成的CdS纳米晶为实心结构,粒径约为20nm,存在较严重的团聚现象.紫外-可见吸收光谱表明:空心CdS纳米晶的吸收波长与实心CdS纳米晶相比蓝移136.74nm,这表明其禁带宽度增大0.11eV.光致发光光谱表明:空心CdS纳米晶的表面缺陷态发射较实心CdS纳米晶有所增强,这是其存在内表面的结果.

By using cadmium chloride and sodium sulfide as raw materials,CdS nanocrystals were synthesized in water phase.The results of transmission electron microscopy（TEM） showed the hollow CdS nanocrystals with uniform wall thickness of 3-5 nm were synthesized at 100 ℃,and the mean grain size of the hollow CdS nanocrystals was 20-30 nm.The solid CdS nanocrystals with mean grain size of 20 nm were obtained at 70 ℃,and serious conglomeration of CdS nanocrystals was found.Comparing with solid CdS nanocrystals,136.74 nm blue shift of hollow CdS nanocrystals absorption wavelength was found by UV-Vis absorption spectroscopy,indicating that the energy gap of hollow CdS nanocrystals was enhanced by 0.11 eV.The results of photoluminescence spectrum indicated that comparing with solid CdS nanocrystals,the surface defect emission of hollow CdS nanocrystals is enhanced because of the presence of inside surface.