Energy transfer in a nanoscale multichromophoric system: Fluorescent dye-doped conjugated polymer nanoparticles
Energy transfer in a nanoscale multichromophoric system: Fluorescent dye-doped conjugated polymer nanoparticles
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DOI：
10.1021/jp074149
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发表时间：
2008-02-14
影响因子：
3.7
通讯作者：
McNeill, Jason
中科院分区：
文献类型：
--
作者：
Wu, Changfeng;Zheng, Yueli;McNeill, Jason
本文报道了掺杂多种荧光染料的聚芴纳米颗粒的荧光特性以及能量扩散和能量转移的联合效应。作为掺杂主体，聚芴具有非凡的“光捕获”能力，与类似尺寸的染料负载二氧化硅纳米颗粒相比，其每颗粒亮度更高。稳态荧光光谱和时间分辨荧光测量表明，从宿主聚合物到受体染料分子的高效能量转移。建立了一个考虑能量扩散、福斯特转移和粒径综合效应的模型。实验数据与模型结果的比较说明了粒子尺寸和聚合物内部能量扩散在决定掺杂共轭聚合物纳米颗粒光学性质中的重要性。对于掺有苝或香豆素6 （2 wt %）的直径为30 nm的聚合物纳米颗粒的水悬浮液，荧光量子产率接近40%，峰消光系数为1.5 × 10(9) M(-1)cm（-1）。光漂白实验表明，能量转移现象强烈影响这些染料掺杂纳米粒子的光稳定性。这些纳米粒子具有高亮度、高红移发射光谱和优异的光稳定性等特点，在生物标记和传感领域具有广阔的应用前景。此外，纳米颗粒是研究致密、纳米结构、多色体系中能量传递的有用模型体系。
We report on the fluorescence properties and the combined effects of energy diffusion and energy transfer in polyfluorene nanoparticles doped with a variety of fluorescent dyes. As the doping host, polyfluorene possesses extraordinary "light harvesting" ability, resulting in higher per-particle brightness as compared to dye-loaded silica nanoparticles of similar dimensions. Both the steady-state fluorescence spectra and time-resolved fluorescence measurements indicate highly efficient energy transfer from the host polymer to the acceptor dye molecules. A model that takes into account the combined effects of energy diffusion, Forster transfer, and particle size was developed. Comparisons of experimental data to the model results elucidate the importance of particle size and energy diffusion within the polymer in determining the optical properties of the doped conjugated polymer nanoparticles. Fluorescence quantum yields of similar to 40% and peak extinction coefficients of 1.5 x 10(9) M(-1)cm(-1) were determined for aqueous suspensions of similar to 30 nm diameter polymer nanoparticles doped with perylene or coumarin 6 (2 wt %). Photobleaching experiments indicate that energy transfer phenomena strongly influence the photostability of these dye-doped nanoparticles. Significant features of these nanoparticles include the high brightness, highly red-shifted emission spectrum, and excellent photostability, which are promising for biological labeling and sensing applications. in addition, the nanoparticles are a useful model system for studying energy transfer in dense, nanostructured, multichromophoric systems.