Biebricher Andreas, Sauer Markus, Tinnefeld Philip
J Phys Chem B. 2006 Mar 23;110(11):5174-8. doi: 10.1021/jp060660b.
Spectrally and time-resolved single-molecule fluorescence spectroscopy was used to investigate fluctuations of the photophysical characteristics of different types of semiconductor nanocrystals (NCs) at room temperature. Correlation of photoluminescence (PL) emission maxima, decay time, and intensity of individual NCs with millisecond time resolution reveals new sources of intensity fluctuations and photophysical properties. In particular, we demonstrate that independent of quenched states spectral diffusion is associated with changes of the radiative rate constant k(r) by means of the quantum-confined Stark effect. Correlation of the different photophysical parameters revealed an intrinsic nonradiative rate and enabled the disentangling of intrinsic and extrinsic nonradiative rate constants. Moreover, it allowed us to assess the PL quantum yield of single NCs. Finally, the presented technique was successfully applied to demonstrate that the addition of antiblinking reagents such as mercaptoethylamine accelerates the observed fluctuations between different photophysical states.
利用光谱和时间分辨单分子荧光光谱技术，在室温下研究了不同类型半导体纳米晶体（NCs）光物理特性的波动情况。以毫秒级时间分辨率对单个NCs的光致发光（PL）发射最大值、衰减时间和强度进行关联，揭示了强度波动和光物理性质的新来源。特别地，我们证明了与猝灭态无关的光谱扩散是通过量子限制斯塔克效应与辐射速率常数k(r)的变化相关联的。不同光物理参数的关联揭示了一个内在的非辐射速率，并能够区分内在和外在的非辐射速率常数。此外，它使我们能够评估单个NCs的PL量子产率。最后，所提出的技术成功地应用于证明添加抗闪烁试剂（如巯基乙胺）会加速在不同光物理状态之间观察到的波动。
