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

在化学系大分子，超分子和纳米化学计划（MSN）和刺激竞争研究的既定计划（EPSCoR）的支持下，阿肯色州大学的Colin Heyes和Robert Coridan正在结合先进的化学合成和分析工具来表征结构，由三种或更多种元素组成的半导体纳米颗粒（直径2 - 10纳米）的光学和电子性质。这些元素取代了半导体纳米颗粒中常用的有毒元素，如镉，而使用了更良性的元素，如铜，铟和锌。然而，关于如何控制包含这些元素的纳米颗粒的光学和电子性质的知之甚少。Heyes，Coridan和他们的学生正在通过系统地改变纳米颗粒的化学合成来解决这种知识的缺乏，并分析这如何影响所得的原子结构，进而影响光学和电子特性。这些发现可能导致新材料用于发光二极管，激光，太阳能转换，催化，化学/生物化学传感器和生物医学成像。这项支持也将用于通过在阿肯色州大学举办的夏季讲习班帮助招募和培训代表性不足的第一代本科生。根据这项奖励，Heyes博士，Coridan博士和他们的学生将研究铜-（锌）-铟硫族化物和银-（锌）-铟硫族化物纳米颗粒量子点（QD），其中CuInE 2或AgInE 2的分布和局部环境（E = S，Se，Te）发射位点随合成条件而变化。已知锌与CuInE 2晶格中的铜和铟进行离子交换以形成合金化Cu（Zn）InE 2 QD，或者与AgInE 2晶格中的银和铟进行离子交换以形成合金化Ag（Zn）InE 2 QD。在我们对这些类型的量子点的理解中有两个重要的差距：（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/激子衰减途径之间的关系是什么？本研究将着手通过系统地合成均匀合金化和异质/梯度合金化的量子点来研究这些知识差距。特别关注的是在单个纳米粒子水平上的光发射特性的异质性，以及将这些特性与使用X射线衍射和光谱技术获得的原子水平结构信息相关联。该奖项反映了NSF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.