Structure-Optoelectronic Property Relationships in Homogeneous and Heterogeneous/Gradient Alloyed Colloidal I-(II)-III-VI Quantum Dots

在化学系大分子、超分子和纳米化学项目（MSN）和促进竞争性研究的已建立项目（EPSCoR）的支持下，阿肯色大学的Colin Heyes和Robert Coridan正在结合先进的化学合成和分析工具来表征由三种或更多元素组成的半导体纳米颗粒（直径2 - 10纳米）的结构、光学和电子特性。这些元素取代了半导体纳米颗粒中常用的有毒元素，如镉，而用更良性的元素，如铜、铟和锌。然而，人们对如何控制包含这些元素的纳米粒子的光学和电子特性知之甚少。Heyes、Coridan和他们的学生正在通过系统地改变纳米粒子的化学合成，并分析这如何影响最终的原子结构，进而影响光学和电子特性，来解决这一知识匮乏的问题。这些发现可能会产生用于发光二极管、激光器、太阳能转换、催化、化学/生化传感器和生物医学成像的新材料。这项支持还将通过在阿肯色大学举办的夏季研讨会，帮助招募和培训代表性不足的第一代本科生。在这个奖项下，dr。Heyes， Coridan和他们的学生将研究铜-（锌）-硫系铟和银-（锌）-硫系铟纳米粒子量子点（QDs），其中CuInE2或AgInE2 （E = S, Se, Te）发射位点的分布和局部环境随合成条件的变化而变化。已知锌在CuInE2晶格中与铜和铟离子交换形成合金Cu(Zn)InE2量子点，或在AgInE2晶格中与银和铟离子交换形成合金Ag(Zn)InE2量子点。我们对这些类型的量子点的理解有两个重要的空白：(i)这种离子交换/合金化的机制是什么；（ii）由特定反应条件产生的结构与电子结构/激子衰变途径之间的关系是什么。本研究将通过系统地合成均匀合金和非均匀/梯度合金量子点来检验这些知识差距。将特别关注单纳米粒子水平的光学发射特性的非均质性，并将这些特性与使用x射线衍射和光谱学技术获得的原子水平结构信息相关联。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

With support from the Macromolecular, Supramolecular and Nanochemistry Program (MSN) in the Division of Chemistry and the Established Program to Stimulate Competitive Research (EPSCoR), Colin Heyes and Robert Coridan of the University of Arkansas are combining advanced chemical synthesis and analysis tools to characterize the structural, optical and electronic properties of semiconducting nanoparticles (2 – 10 nanometers in diameter) composed of three or more elements. These elements replace toxic elements that are commonly used in semiconducting nanoparticles, such as cadmium, with more benign ones, such as copper, indium and zinc. However, much less is known about how to control the optical and electronic properties of nanoparticles incorporating these elements. Heyes, Coridan and their students are addressing this lack of knowledge by systematically varying the chemical synthesis of the nanoparticles and analyzing how this affects the resulting atomic structure and, in turn, the optical and electronic properties. These discoveries could lead to new materials for use in light emitting diodes, lasers, solar energy conversion, catalysis, chemical/biochemical sensors, and biomedical imaging. This support will also be used to help recruit and train underrepresented and first generation undergraduate students through summer workshops to be held at the University of Arkansas.Under this award, Drs. Heyes, Coridan and their students will study copper-(zinc)-indium chalcogenide and silver-(zinc)-indium chalcogenide nanoparticle quantum dots (QDs) in which the distribution and local environment of the CuInE2 or AgInE2 (E = S, Se, Te) emitting sites is varied by the synthesis conditions. Zinc is known to ion exchange with copper and indium in the CuInE2 lattice to form alloyed Cu(Zn)InE2 QDs or with silver and indium in the AgInE2 lattice to form alloyed Ag(Zn)InE2 QDs. Two important gaps in our understanding of these types of QDs are (i) What is the mechanism underlying this ion-exchange/alloying and (ii) what is the relationship between the structure resulting from the specific reaction conditions and the electronic structure/exciton decay pathways. This research will set out to examine these knowledge gaps by systematically synthesizing homogeneously alloyed and heterogeneous/gradient alloyed QDs. Particular attention will be paid to the heterogeneity in optical emission properties at the single nanoparticle level and in correlating these properties to atomic level structural information obtained using X-ray diffraction and spectroscopy techniques.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.