Chen Jia-Shiang, Li Mingxing, Cotlet Mircea
Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States.
Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, New York 11794, United States.
ACS Omega. 2019 May 23;4(5):9102-9112. doi: 10.1021/acsomega.9b00803. eCollection 2019 May 31.
Semiconducting colloidal quantum dots (QDs) provide an excellent platform for nanoscale charge-transfer studies. Because of their size-dependent optoelectronic properties, which can be tuned via chemical synthesis and of their versatility in surface ligand exchange, QDs can be coupled with various types of acceptors to create hybrids with controlled type (electron or hole), direction, and rate of charge flow, depending on the foreseen application, either solar harvesting, light emitting, or biosensing. This perspective highlights several examples of QD-based hybrids with controllable (tunable) rate of charge transfer obtained by various approaches, including by changing the QD core size and shell thickness by colloidal synthesis, by the insertion of molecular linkers or dielectric spacers between donor and acceptor components. We also show that subjecting QDs to external factors such as electric fields and alternate optical excitation energy is another approach to bias the internal charge transfer between charges photogenerated in the QD core and QD's surface charge traps. The perspective also provides the reader with various examples of how single nanoparticle spectroscopic studies can help in understanding and quantifying nanoscale charge transfer with QDs.
半导体胶体量子点（QDs）为纳米级电荷转移研究提供了一个出色的平台。由于其与尺寸相关的光电特性（可通过化学合成进行调节）以及在表面配体交换方面的多功能性，量子点可以与各种类型的受体耦合，以创建具有可控类型（电子或空穴）、方向和电荷流动速率的杂化体，这取决于预期的应用，无论是太阳能收集、发光还是生物传感。本综述重点介绍了通过各种方法获得的具有可控（可调）电荷转移速率的基于量子点的杂化体的几个例子，包括通过胶体合成改变量子点的核尺寸和壳层厚度，通过在供体和受体组分之间插入分子连接体或介电间隔物。我们还表明，使量子点受到外部因素（如电场和交替的光激发能量）的影响是另一种使在量子点核中光生电荷与量子点表面电荷陷阱之间的内部电荷转移产生偏差的方法。本综述还为读者提供了各种例子，说明单纳米颗粒光谱研究如何有助于理解和量化与量子点相关的纳米级电荷转移。
