CREST-Postdoctoral Research Fellowship: The Effects of Strong Confinement in the Ultrasmall Nanoparticle Regime on the Mechanism and Charge Transfer Rates in CdSe QDs

CREST项目中的科学和技术卓越研究中心-博士后研究奖学金(CREST-PRF)轨道为CREST中心具有巨大潜力的初学者提供支持，并为他们提供培训和研究经验，这些培训和研究经验将拓宽视野，促进跨学科互动，并使他们在科学界处于领导地位。该CREST-PRF项目与纽约城市学院CREST接口设计和低维结构工程组装中心的研究重点相一致。本研究的目的是了解超小的CdSe量子点(QD)的光电性质。量子点是纳米级的，这导致了不同于较大粒子的光学和电学性质。量子点有可能挖掘太阳能的巨大潜力。这项拟议的工作旨在利用X射线光谱和透射电子显微镜技术来研究研究人员合成的超小量子点。这些技术将使研究人员更全面地了解超小量子点的电荷转移能力，并建立理论模型来解释这一行为。这项分析将允许在太阳能电池设计中加入超小量子点。尽管超小的量子点是单分散的，但它们表现出广泛的发射。光致发光激发(PLE)将允许研究哪些激发波长可以导致特定波长的发射。初步的PLE数据表明，在带隙内有可能直接吸收的态。从量子点收集的PLE数据将与时间分辨光致发光数据(TRPL)进行比较。TRPL允许人们检测多指数衰减系统，这表明这类系统具有多个寿命。用X射线光电子能谱(XPS)和透射电子显微镜(TEM)对两种受体物种进行了研究。受体物种包括a)同时具有电子供体和接受电子特性的分子(配体)和b)碳纳米管(CNTs)。这些分子将从研究不同链长的烷基硫醇和一水苯磺酸(BSAM)开始。量子点将被嵌入到碳纳米管中，不仅作为一种增强电荷转移的手段，而且还作为量子点之间连接的量子点对齐的一种手段。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The Centers of Research Excellence in Science and Technology-Postdoctoral Research Fellowship (CREST-PRF) track within the CREST program supports beginning CREST Center investigators with significant potential and provides them with training and research experiences that will broaden perspectives, facilitate interdisciplinary interactions and establish them in positions of leadership within the scientific community. This CREST-PRF project is aligned with the research focus of the CREST Center for Interface Design and Engineered Assembly of Low Dimensional Structures (CREST-IDEALS) at the City College of New York. The goal of this research is understanding the optoelectronic properties of ultrasmall CdSe quantum dots (QDs). Quantum Dots are on the nano scale which results in optical and electronic properties that are different from larger particles. QDs have the potential to tap into the enormous potential of Solar Energy. The proposed work intends to investigate ultrasmall quantum dots synthesized by the researcher with x-ray spectroscopy and transmission electron microscopy techniques. These techniques will allow the researcher to more fully understand the ability of ultrasmall quantum dots to transfer charge and formulate a theoretical model to explain the behavior. This analysis will allow the incorporation of ultrasmall QDs into solar cell designs. Ultrasmall quantum dots display broad emission despite their monodispersity. Photoluminescence excitation (PLE) will allow for the investigation of which excitation wavelengths can cause the emission of a specified wavelength. Preliminary PLE data indicates that there are states within the bandgap to which direct absorption is possible. PLE data gathered from Qds will be compared to time resolved photoluminescence data (TRPL). The TRPL allows one to detect multiexponential decay systems, indicating that such systems have multiple lifetimes. Two acceptor species will be investigated with x-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The acceptor species include a) molecules (ligands) of both e- donating and e- accepting character and b) carbon nanotubes (CNTs). The molecules will begin with investigating alkylthiols of varying chain length and benzene sulfonic monohydrate (BSAM). Qds will be embedded within CNTs as a means of not only charge transfer enhancement but also QD alignment for connectivity between QDs as well.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.