Data from: Distance and wavelength dependent quenching of molecular fluorescence by Au@SiO2 core-shell nanoparticles

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Gold nanoparticles and nearby fluorophores interact via electromagnetic coupling upon light excitation. We determine the distance and wavelength dependence of this coupling theoretically and experimentally via steady-state and time-resolved fluorescence spectroscopy. For the first time, the fluorescence quenching of four different dye molecules, which absorb light at different wavelengths across the visible spectrum and into the near-infrared, is studied using a rigid silica shell as a spacer. A comprehensive experimental determination of the distance dependence from complete quenching to no coupling is carried out by a systematic variation of the silica shell thickness. Electrodynamic theory predicts the observed quenching quantitatively in terms of energy transfer from the molecular emitter to the gold nanoparticle. The plasmonic field enhancement in the vicinity of the 13 nm gold nanoparticles is calculated as a function of distance and excitation wavelength and is included in all calculations. Relative radiative and energy transfer rates are determined experimentally and are in good agreement with calculated rates. We demonstrate and quantify the severe effect of dye-dye interactions on the fluorescence properties of dyes attached to the surface of a silica nanoparticle in control experiments. This allows us to determine the experimental conditions, under which dye-dye interactions do not affect the experimental results.

所附文件为关联文章提供补充数据。金纳米颗粒与邻近荧光团在光激发下会通过电磁耦合发生相互作用。本研究通过稳态及时间分辨荧光光谱法，从理论与实验两方面阐明了该耦合作用的距离与波长依赖特性。本次研究首次以刚性二氧化硅壳层作为间隔层，针对四种吸光波长覆盖可见光光谱至近红外波段的不同染料分子的荧光猝灭现象展开探究。通过系统性调控二氧化硅壳层厚度，我们完成了从完全猝灭至无耦合状态的距离依赖性综合实验测定。电动力学理论可通过分子发射体向金纳米颗粒的能量转移机制，定量预测本研究观测到的猝灭现象。13 nm金纳米颗粒周边的等离激元场增强效应，已被计算为距离与激发波长的函数，并纳入所有计算环节。研究人员通过实验测定了相对辐射速率与能量转移速率，其结果与理论计算值吻合良好。我们在对照实验中证实并量化了染料-染料相互作用对附着于二氧化硅纳米颗粒表面的染料荧光特性的显著影响，借此明确了染料-染料相互作用不会干扰实验结果的实验条件。