...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>The journal of physical chemistry, C. Nanomaterials and interfaces >Fluorescence Dynamics of Semiconductor Nanorod Clusters Studied by Correlated Atomic Force, Transmission Electron, and Fluorescence Microscopy
【24h】

Fluorescence Dynamics of Semiconductor Nanorod Clusters Studied by Correlated Atomic Force, Transmission Electron, and Fluorescence Microscopy

机译：用相关原子力，透射电子和荧光显微镜研究半导体纳米棒团簇的荧光动力学

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Semiconductor nanocrystals have a wide range of applications as light emitters, especially in biomedical imaging. Elongated core—shell CdSe-based nanocrystals (nanorods) are particularly interesting as fluorescent markers because of their large absorption cross section, large surface area, and high brightness. While light intermittency ("blinking") in single nanorods has been studied previously, here we report the fluorescence properties of core—shell CdSe-based nanorod clusters. The time-dependent cluster fluorescence was correlated with the particle number by direct particle counting (from single nanoparticles to ～10 000), cluster area, and the orientation and distribution of individual nanorods within these clusters. This was uniquely enabled by combined transmission electron and atomic force microscopy. In contrast to the "on/off emission in single nanorods, we show that nanorod clusters containing as few as five nanorods exhibit a nonzero residual fluorescence in the "dark state"; that is, they can be "on" continuously, within the measurement time window of several tens of minutes. With increasing particle number, the cluster fluorescence increases in intensity and the relative fluorescence fluctuations, originating from single particle events, decrease in accordance with the central limit theorem. We report the effects of assembly patterns and nanorod orientation (on the silicon nitride substrate and relative to the laser polarization) on the fluorescence properties of the clusters. The fluorescence time-dependence of nanorod clusters at long time-scales, i.e. tens of hours, follows two characteristic trends depending on particle number and laser intensity. These data are compared to predictions made by a statistical model derived from single-particle dynamics. Finally, to investigate the possible role of charge traps on ensemble properties, we have also confirmed by electrical measurements across nanorod arrays that the electrical current exhibits statistical aging and memory effects. This complementary measurement provides a new way to relate the electrical and optical properties of nanoparticle ensembles and further suggests that filling of charge traps can possibly explain both the fluorescence and the anomalous transport dynamics of core—shell nanorod ensembles.
机译：半导体纳米晶体作为发光体具有广泛的应用，特别是在生物医学成像中。细长的基于核壳的CdSe基纳米晶体（nanorods）作为荧光标记特别有趣，因为它们的吸收截面大，表面积大且亮度高。虽然先前已经研究了单个纳米棒中的光间歇性（“闪烁”），但在这里我们报道了基于核壳CdSe的纳米棒簇的荧光特性。通过直接粒子计数（从单个纳米粒子到约10000个粒子），簇的面积以及这些簇中单个纳米棒的方向和分布，随时间变化的簇荧光与颗粒数量相关。结合了透射电子和原子力显微镜，这是独一无二的。与“单个纳米棒中的开/关发射”相反，我们表明，包含多达五个纳米棒的纳米棒簇在“暗态”下显示出非零残留荧光;也就是说，在测量范围内，它们可以连续“打开”几十分钟的时间窗口，随着粒子数量的增加，团簇荧光的强度增加，源自单个粒子事件的相对荧光波动根据中心极限定理减少，我们报道了组装模式和纳米棒取向的影响（在氮化硅衬底上并且相对于激光偏振）团簇的荧光特性。纳米棒团簇在长时间范围内（即数十小时）的荧光时间依赖性遵循两个特征趋势，这取决于颗粒数和激光将这些数据与由单粒子动力学得出的统计模型的预测结果进行比较。关于电荷陷阱对整体性能的可能作用，我们还通过跨纳米棒阵列的电学测量证实，电流表现出统计学的老化和记忆效应。这种互补的测量提供了一种新的方式来关联纳米粒子集合体的电学和光学性质，并且进一步表明电荷陷阱的填充可以解释荧光和核-壳纳米棒集合体的异常运输动力学。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号