Department of Physics, University of Alabama in Huntsville, Huntsville, AL 35899, USA.
Nanotechnology. 2011 Oct 7;22(40):405202. doi: 10.1088/0957-4484/22/40/405202. Epub 2011 Sep 7.
Emission of semiconductor quantum dots can be increased via two fundamentally different processes: (i) surface plasmon resonances (plasmonic emission enhancement) and (ii) irradiation with light (photo-induced fluorescence enhancement). In this paper we theoretically and experimentally study the mutual impacts of these processes on each other in quantum dot solids. We show that when thin films of colloidal quantum dots are placed in the vicinity of Au nano-islands, the plasmonic enhancement of the radiative decay rates of quantum dots and Forster energy transfer can hinder the photo-induced fluorescence enhancement of these films. This in turn leads to significant suppression of their plasmonic emission enhancement when they are irradiated with a laser beam. We investigate the impact of the sizes and shapes of the metallic nanoparticles in this process and theoretically analyze how plasmons and energy transfer can hinder the electrostatic barrier responsible for photo-induced fluorescence enhancement.
(i) 表面等离子体共振（等离子体发射增强）和 (ii) 光照射（光致荧光增强）。在本文中，我们从理论和实验上研究了这些过程在量子点固体中的相互影响。我们表明，当胶体量子点的薄膜放置在 Au 纳米岛附近时，量子点的辐射衰减率的等离子体增强和Förster 能量转移可以阻碍这些薄膜的光致荧光增强。这反过来又导致当它们被激光照射时，它们的等离子体发射增强显著抑制。我们研究了在这个过程中金属纳米粒子的大小和形状的影响，并从理论上分析了等离子体和能量转移如何阻碍光致荧光增强的静电势垒。
