界面电子转移对量子点荧光闪烁行为的影响

Influence of interfacial electron transfer on fluorescence blinking of quantum dots

利用激光扫描共聚焦显微系统分别测量了CdSe/ZnS量子点在SiO2玻片表面、铟锡氧化物(ITO)纳米粒子表面和聚甲基丙烯酸甲酯(PMMA)薄膜表面上的荧光闪烁行为.研究发现,不同界面环境中量子点的亮态发光持续时间的概率密度都服从指数修正的幂律分布P(t)∝t-αexp(-t/μ).与处于SiO2玻片表面的情况相比,在ITO表面上的单量子点具有非常短暂的亮态发光持续时间,而在PMMA表面的单量子点亮态发光持续时间最长.这种荧光闪烁行为的不同主要归因于量子点与三种材料之间的界面电子转移特性.

The fluorescence blinking characteristics of the single CdSe/ZnS core/shell quantum dots （QDs） absorbed on the cover glass surface, indium-tin oxide （ITO） nanoparticles, and polymethyl methacrylate （PMMA） film surface are mea-sured by a laser scanning confocal fluorescence microscopy. It is found that all the distributions of bright state duration time of QDs on the three different interfaces can be described by a truncated power law P （t） ∝ t-αexp（-t/μ）. The statistical on-time durations of single QDs absorbed on the ITO nanoparticles is shorter than on the glass. In addition, the on-time duration with single QDs absorbed on the PMMA is longer than on the others. These differences can be attributed to the diverse interfacial electron transfers between QD and different materials.