紫外辐照增强ZnS纳米晶发光性质的研究

Enhanced luminescence of ZnS nanocrystals by ultraviolet irradiation

采用化学沉淀法合成了规则的球状ZnS纳米晶,在Zn原料过量不同的条件下,得到的ZnS纳米晶发光强度不同。利用吸收光谱、发射光谱和透射电子显微镜对其光学特性和形貌进行了研究,发现ZnS纳米晶在424 nm处有一个与填隙原子或空位态原子等缺陷态有关的发射,归因于电子由浅施主能级向Zn空位形成的深能级受主跃迁产生。同时还观察到了在480 nm左右的伴峰出现,归因于ZnS表面S悬空键的发射。最后通过紫外辐照,使得纳米晶的表面生成了一层包覆体,降低了表面缺陷,增强了ZnS纳米晶的本征发光,发光强度随着辐照时间增加而增强,最后由于纳米晶表面不再变化而趋于稳定。

In this paper,regular sphetical ZnS nanocrystals were prepared via chemical precipitation method.The luminous intensity of ZnS nanocrystals were different for raw material of Zn excess different.Absorption spectra,Emission spectra and TEM were employed to study the luminescence properties,and the results showed that the photoluminescence spectrum peaking at about 424 nm,were due mostly to the trap-state emission,and a satellite peak at 480 nm ascribed to the dangling bond of S in the surface of ZnS nanocrystals.The emission intensity of ZnS was enhanced after ultraviolet irradiation,the enhancement of the Photoluminescence intensity was due to the elimination of the surface defects after ultraviolet irradiation,for the growth of the coated shell on ZnS nonacrystals,the Photoluminescence intensity was increased as ultraviolet irradiation time growth,finally tends to be stable for the surface state of nanocrystals steady.