School of Physics and CRANN, Trinity College, Dublin 2, Ireland.
ACS Nano. 2012 Oct 23;6(10):9283-90. doi: 10.1021/nn303756a. Epub 2012 Sep 20.
Nonradiative energy transfer to metal nanoparticles is a technique used for optical-based distance measurements which is often implemented in sensing. Both Förster resonant energy transfer (FRET) and nanometal surface energy transfer (NSET) mechanisms have been proposed for emission quenching in proximity to metal nanoparticles. Here quenching of emission of colloidal quantum dots in proximity to a monolayer of gold nanoparticles is investigated. Five differently sized CdTe quantum dots are used to probe the wavelength dependence of the quenching mechanism as their emission peak moves from on resonance to off resonance with respect to the localized surface plasmon peak of the gold nanoparticle layer. The gold nanoparticle concentration and distance dependences of energy transfer are discussed. Photoluminescence quenching and lifetime data are analyzed using both FRET and NSET models and the extracted characteristic distances are compared with theory. Good agreement with FRET theory has been found for quantum dots with emission close to the localized surface plasmon resonance, though larger than expected Förster radii are observed for quantum dots with emission red-shifted with respect to the localized surface plasmon peak. Closer agreement between experimental and theoretical characteristic distances can be found across the full wavelength range within a NSET approach.
非辐射能量转移到金属纳米粒子是一种用于基于光学的距离测量的技术，通常在传感中实现。Förster 共振能量转移（FRET）和纳米金属表面能量转移（NSET）机制都被提出用于在金属纳米粒子附近的发射猝灭。在这里，研究了胶体量子点在单层金纳米粒子附近的发射猝灭。使用五个不同尺寸的 CdTe 量子点来探测猝灭机制的波长依赖性，因为它们的发射峰从与金纳米粒子层的局域表面等离子体峰共振移动到离共振。讨论了能量转移的金纳米粒子浓度和距离依赖性。使用 FRET 和 NSET 模型分析光致发光猝灭和寿命数据，并将提取的特征距离与理论进行比较。对于接近局域表面等离子体共振的量子点，与 FRET 理论有很好的一致性，尽管对于发射相对于局域表面等离子体峰红移的量子点，观察到比预期大的Förster 半径。在 NSET 方法中，可以在整个波长范围内找到更接近实验和理论特征距离的一致性。
