纳米ZnS∶Mn荧光粉的余辉研究  

Luminescent Decay of Nanocrystal ZnS∶Mn Phosphor

作　　者：郭常新[1,2,3] 李碧琳[4] 

机构地区：[1]中国科学技术大学物理系 [2]中国科学院激发态物理开放实验室,吉林长春130021 [3]中国科学技术大学结构分析开放实验室,安徽合肥230026 [4]中国科学院激发态物理开放实验室

出　　处：《发光学报》2001年第3期223-226,共4页Chinese Journal of Luminescence

基　　金：国家自然科学基金 ( 195 740 46 ) ;中国科学院激发态物理开放实验室和中国科学技术大学结构分析开放实验室资助项目

摘　　要：用无机材料在室温下通过溶胶法制成了纳米ZnS∶Mn荧光粉 ,立方晶形 ,平均粒径为 3nm ,它的橙色发光 (峰值 6 0 8nm ,半宽 75nm)亮度与同晶型 (立方 )的体ZnS∶Mn荧光粉的亮度相同 ,而余辉缩短。在Nd∶YAG四倍频 2 6 6nm脉冲激光激发下 ,仔细对立方纳米、纯立方微米、纯六角微米ZnS∶Mn荧光粉进行了余辉的对比测量。它们的余辉主要遵循指数衰减规律 ,其 1/e余辉时间的结果如下 :(1)纯立方纳米ZnS∶Mn :两个指数衰减 ,余辉时间分别为 186 μs和10 78μs,其幅度比为 4∶1,前者是主要的 ,决定了 1/e余辉时间 ,(2 )纯立方微米体ZnS∶Mn :944 μs,(3)纯六角微米体ZnS∶Mn :1 2ms(还有幅度很小的极长余辉成分 )。结果表明纳米ZnS∶Mn荧光粉的光致发光余辉的确比对应的体材料 (不管是六角还是立方 )都短 ,但余辉仅缩短了几倍 。Nanocrystal ZnS∶Mn phosphor has been prepared by sol method using inorganic materials at room temperature. The nanocrystal phosphor of ZnS∶Mn has cubic crystal structure with average 3nm of particle size, emitting bright orange light at peak wavelength 608nm with the full width of half maximum 75nm under UV 365nm excitation, and the brightness as high as the corresponding bulk pure cubic ZnS∶Mn phosphor. According to the results reported by R.N.Bhargava, in comparison with the bulk ZnS∶Mn phosphor the nanocrystal ZnS∶Mn has nearly high luminescent efficiency with its luminescent decay time at least 5 orders of magnitude faster. It means that the oscillator intensity of luminescent centers in nanocrystal ZnS∶Mn enhances at least 5 orders of magnitude than that in corresponding bulk ZnS∶Mn. The discovery of high luminescent efficiency nanocrystal phosphor ZnS∶Mn aroused the great interest to lots of researchers in the world. But these results are difficult to explain according to the normal concept. So checking these results by experiment has very important meaning in theory and experiment. In this paper the main purpose is to make a luminescent decay comparison between the nanocrystal and normal bulk crystal (particle size in micrometer) ZnS∶Mn phosphors. In this comparison we controlled two factors: (1) The nanometer and bulk ones need have same crystal structure. A commercial bulk ZnS∶Mn phosphor usually has mixed structure of cubic and hexagonal crystal which mainly depends on the sintering temperature and the doping concentration of luminescent activator Mn 2+ . In our experiments, under two different sintering conditions we prepared the bulk phosphors in two pure structures, cubic and hexagonal, respectively. These bulk crystal ZnS∶Mn phosphors have the average particle size in micrometer order of magnitude. (2) Luminescent decay will sensitively depend upon the excitation condition, such as excitation intensity and mode like photoluminescence (PL) and cathodeluminescence (CL). In

关 键 词：纳米荧光粉 ZNS:MN 光致发光 余辉 无机材料 指数衰减 

分 类 号：TN104.3[电子电信—物理电子学] O482.31[理学—固体物理]