Bioconjugates of CdTe nanowires and Au nanoparticles: Plasmon-exciton interactions, luminescence enhancement, and collective effects
Bioconjugates of CdTe nanowires and Au nanoparticles: Plasmon-exciton interactions, luminescence enhancement, and collective effects
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DOI：
10.1021/nl048669h
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发表时间：
2004-12-01
期刊：
影响因子：
10.8
通讯作者：
Kotov, NA
中科院分区：
文献类型：
--
作者：
Lee, J;Govorov, AO;Kotov, NA
通过生物共轭反应制备由 CdTe 纳米线 (NW) 和金属纳米粒子 (NP) 制成的纳米级超结构。原型生物分子，例如 D-生物素和链霉亲和素对，被用来连接溶液中的纳米粒子和纳米线。研究发现 Au 纳米颗粒在 CdTe 纳米线周围形成致密的壳层。上部结构表现出与半导体和贵金属纳米胶体的长距离相互作用相关的不寻常的光学效应。与未共轭的 NW 相比，NW-NP 复合物的发光强度增强了 5 倍，并且发射峰发生蓝移。该系统在由金壳同轴包围的 CdTe NW 简单模型中进行了理论上的检验，结果与实验数据非常吻合。时间分辨发光和计算的结合表明，荧光强度的增加是由于金纳米粒子周围产生的电磁场刺激光子发射而发生的。该过程让人想起 SERS，尽管显示出较小的增强因子。重要的是，发光增强应被视为 Au-NP 的集体响应，而不是孤立的 NP-NW 相互作用的结果。
Nanoscale superstructures made from CdTe nanowires (NWs) and metal nanoparticles (NPs) are prepared via bioconjugation reactions. Prototypical biomolecules, such as D-biotin and streptavidin pair, were utilized to connect NPs and NWs in solution. It was found that Au NPs form a dense shell around a CdTe NW. The superstructure demonstrated unusual optical effects related to the long-distance interaction of the semiconductor and noble metal nanocolloids. The NW-NP complex showed 5-fold enhancement of luminescence intensity and a blue shift of the emission peak as compared to unconjugated NW. The system was theoretically examined in a simple model of CdTe NW coaxially surrounded by an Au shell, which gives excellent agreement with experimental data. The combination of time-resolved luminescence and calculations demonstrated that increase of fluorescence intensity occurs due to stimulation of photon emission by an electromagnetic field generated around the Au NP. The process is reminiscent of SERS, although displaying smaller enhancement factors. Importantly, the luminescence enhancement should be treated as a collective response of Au-NPs, rather than a result of isolated NP-NW interactions.