纳米ZnS∶Mn^(2+)薄膜荧光增强动力学研究  

Dynamics of Luminescence Enhancement of ZnS∶Mn^( 2+) Nanoparticle Dispersed in PVB Film

作　　者：任山令[1] 张家骅[1] 吕少哲[1] 曹立新[1] 宋宏伟[1] 黄世华[1] 

机构地区：[1]中国科学院长春光学精密机械与物理研究所激发态物理重点实验室,吉林长春130022

出　　处：《发光学报》2002年第5期451-455,共5页Chinese Journal of Luminescence

基　　金：国家自然科学基金资助项目 (5 0 172 0 47) ;国家重点基础研究规划项目 (G19980 613 0 9)

摘　　要：利用有机溶胶方法制备了纳米ZnS∶Mn2 + 颗粒并将其分散在PVB薄膜中 ,观察到紫外辐照荧光增强的现象且增长倍数高于以前的报道。利用激发和发射光谱等手段对荧光增强的动力学过程进行了研究。认为纳米ZnS中元激发向Mn2 + 离子和表面态的能量传递是两个互相竞争的过程 ,紫外光辐照使表面态数目减少从而使Mn2 + 的发光增强 ,辐照后ZnS基质的 1P能级对Mn的激发更为有效。该样品在太阳光辐照下有相同的增强效应 。ZnS∶Mn 2+ nanoparticle synthesized by chemical colloid method has been dispersed into PVB ethanol colloid to form organic film. From the emission spectra before and after UV 290nm irradiation, the luminescence peaked at 580nm of Mn 2+ 4T 1 → 6A 1 transition has a higher enhancement than that ever reported under UV 300nm excitation. The emission spectra, excitation spectra and time dependent luminescence growth were employed to determine the dynamics of the irradiation induced luminescence enhancement effect (RILE). The excitation spectra after irradiation showed that there are two excitation peaks,which are corresponding to the 1S and 1P energy state of ZnS, respectively. The 1S excitation peak's shift to the high energy compared with the bulk materials induced by the quantum confine effect, indicates that the average size of nanoparticles is around 3nm by the theory of Effect Mass Approximation (EMA). With the UV irradiation, the shape of excitation spectra changed .The original 1P excitation peak grows more rapidly than the 1S excitation peak and get a higher value when the increment came to saturation. Dynamics of luminescence is investigated. We consider that surface state can quench the luminescence of Mn 2+ . With the irradiation, the surface state decreases and therefore luminescence of Mn 2+ increases. By fitting the experimental data, we find that the relaxation rate from 1P to quenching center has a linear relation with that from 1S to quenching center. We conclude that both 1P and 1S state can relax to quenching center. The enhancement is stable because the reduction of quenching centers is irreversibility. The sample has the same RILE effect after exposure to the natural light, so it can used as a new type of material to measure the dosage of UV irradiation.

关 键 词：ZnS:Mn^2+薄膜 荧光增强动力学 荧光光谱 纳米材料 锰离子掺杂 硫化锌薄膜 

分 类 号：O484.41[理学—固体物理] TB383[理学—物理]