Department of Chemistry & Biochemistry, University of California, Santa Cruz, CA 95064 USA, Fax: (831) 459-3776.
Adv Mater. 2013 Jun 4;25(21):2878-96. doi: 10.1002/adma.201300362. Epub 2013 Apr 26.
This review article provides an overview of recent advances in the study and understanding of dynamics of excitons in semiconductor nanocrystals (NCs) or quantum dots (QDs). Emphasis is placed on the relationship between exciton dynamics and optical properties, both linear and nonlinear. We also focus on the unique aspects of exciton dynamics in semiconductor NCs as compared to those in bulk crystals. Various experimental techniques for probing exciton dynamics, particularly time-resolved laser methods, are reviewed. Relevant models and computational studies are also briefly presented. By comparing different materials systems, a unifying picture is proposed to account for the major dynamic features of excitons in semiconductor QDs. While the specific dynamic processes involved are material-dependent, key processes can be identified for all the materials that include electronic dephasing, intraband relaxation, trapping, and interband recombination of free and trapped charge carriers (electron and hole). Exciton dynamics play a critical role in the fundamental properties and functionalities of nanomaterials of interest for a variety of applications including optical detectors, solar energy conversion, lasers, and sensors. A better understanding of exciton dynamics in nanomaterials is thus important both fundamentally and technologically.
这篇综述文章概述了半导体纳米晶体（NCs）或量子点（QDs）中激子动力学研究和理解的最新进展。重点介绍了激子动力学与线性和非线性光学性质之间的关系。我们还重点关注了与体晶体相比，半导体 NCs 中激子动力学的独特方面。本文回顾了各种探测激子动力学的实验技术，特别是时间分辨激光方法。还简要介绍了相关的模型和计算研究。通过比较不同的材料体系，提出了一个统一的图像来解释半导体 QDs 中激子的主要动力学特征。虽然所涉及的具体动态过程取决于材料，但可以为所有材料确定关键过程，这些过程包括电子退相、带内弛豫、俘获和自由和俘获电荷载流子（电子和空穴）的带间复合。激子动力学在各种应用中，包括光探测器、太阳能转换、激光和传感器等，对感兴趣的纳米材料的基本性质和功能起着关键作用。因此，从根本上和技术上更好地理解纳米材料中的激子动力学是非常重要的。
