Organic Ligand Induced Chiroptical Semiconductor Nanomaterials

有机配体诱导手性半导体纳米材料

• 批准号: 1508593
• 负责人: Milan Balaz
• 金额: $ 60万
• 依托单位: University of Wyoming
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-15 至 2016-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1508593&HistoricalAwards=false
• 关键词: Organic; Ligand; Induced; Chiroptical; Semiconductor

The Macromolecular, Supramolecular, and Nanochemistry (MSN) Program at NSF is supporting Professors Balaz, Dahnovsky, Kubelka, Varga and their respective groups to study the optical properties of semi-conductor quantum dots (QDs). These are nanometer size crystals made of semiconductor materials. Their spectroscopic properties, such as light absorption and light emission, are closely connected to their size, shape and environment. Amino acids are building blocks of proteins and can exist in two mirror-image structural forms: right-handed and left-handed. Yet, all essential amino acids are left-handed. Placing a left-handed amino acid on the surface of QDs causes the crystal to distinguish between "left-handed light" and "right-handed light". The project aims to understand this interesting phenomenon on a molecular level. The unique properties of mirror-image QDs promise a broad range of new applications in research and technology including memory devices and new light-emitting materials and sensors. The research provides graduate and undergraduate students at the University of Wyoming (UW) with new, exciting research and educational opportunities in a cutting-edge interdisciplinary scientific area. The outcomes of this research are shared in peer-reviewed publications, at regional, national and international meetings, as well as at Wyoming Community Colleges and High Schools. New experiments focusing on QDs are introduced into UW undergraduate curriculum. Quantum dots (QDs) are semiconductor nanocrystals with potentially unique properties, which arise from the sensitivity of their electronic properties to the QD size and environment. Previous research in Balaz lab has shown that L- and D-enantiomers of the amino acid cysteine induce mirror image circular dichroism and circularly polarized luminescence in achiral QDs. Coupled with quantum size effect, the post-synthetic ligand exchange represents an appealing approach to induce and tune chiroptical characteristics of QDs. The objective of this project is to determine the origin of chiral capping ligand-induced chiroptical activity of achiral QDs using a combination of experimental and theoretical approaches. The project explores: (i) the structural and electronic requirements of QDs as well as chiral capping ligands to induce and tune chiroptical activity of QDs, (ii) the binding geometry of chiral ligands to the surface of QDs, and (iii) fundamental understanding of the origins of the induced chirality through theoretical simulations of ligand induced CD spectra in QDs and their comparison with the experimental CD data. Knowledge acquired within the proposed research is being applied for the development of chiral memory devices, light-emitting nanomaterials, and QD-based devices for chiroptical sensing of chiral biomolecules.

NSF的大分子、超分子和纳米化学(MSN)计划正在支持Balaz、Dahnovsky、Kubelka、Varga教授和他们各自的小组研究半导体量子点(QD)的光学性质。这些是由半导体材料制成的纳米级晶体。它们的光谱性质，如光吸收和光发射，与它们的大小、形状和环境密切相关。氨基酸是蛋白质的组成部分，可以以两种镜像结构形式存在：右手和左手。然而，所有必需的氨基酸都是左撇子。在量子点的表面放置一种左手氨基酸，可以使晶体区分“左手光”和“右手光”。该项目旨在从分子水平上理解这一有趣的现象。镜像量子点的独特性质在研究和技术方面具有广泛的新应用前景，包括存储设备和新的发光材料和传感器。这项研究为怀俄明大学(UW)的研究生和本科生在尖端跨学科科学领域提供了新的、令人兴奋的研究和教育机会。这项研究的结果在同行评议的出版物、区域、国家和国际会议以及怀俄明州社区学院和高中分享。威斯康星州大学本科课程引入了以量子点为重点的新实验。量子点是一种具有潜在独特性质的半导体纳米晶体，它的电子性质对量子点的大小和环境非常敏感。巴拉兹实验室先前的研究表明，氨基酸半胱氨酸的L和D-对映体在非手性量子点中诱导镜像圆二色和圆偏振发光。再加上量子尺寸效应，合成后的配体交换是诱导和调节量子点手性特征的一种有吸引力的方法。本项目的目的是通过实验和理论相结合的方法来确定手性封端配体诱导的非手性量子点手性活性的来源。该项目探索了：(I)诱导和调节量子点手性活性的量子点和手性封端配体的结构和电子要求，(Ii)手性配体与量子点表面的结合几何，以及(Iii)通过对量子点中配体诱导的CD光谱的理论模拟以及它们与实验CD数据的比较，对诱导手性的起源有了基本的理解。在拟议研究中获得的知识正被应用于手性存储器件、发光纳米材料和用于手性生物分子手性传感的基于量子点的器件的开发。