Semiconductor Nanocrystals, Gold Nanostructures, Toxic Metals in the Environment

半导体纳米晶体、金纳米结构、环境中的有毒金属

• 批准号: RGPIN-2015-05692
• 负责人: Hamilton, Ian
• 金额: $ 1.46万
• 依托单位: Wilfrid Laurier University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=677286
• 关键词: Semiconductor; Nanocrystals; Gold; Nanostructures; Toxic

On the computational side, my research program seeks to model and thereby understand the properties of (i) semiconductor nanocrystals, (ii) gold nanostructures, and (iii) toxic metals in the environment. On the theoretical side, my research program seeks to (i) examine the quantum potential as a measure of reactivity and bonding and (ii) obtain an accurate expression for the kinetic energy that is a direct functional of the electron density. For ground state calculations we primarily use the Kohn-Sham formulation of density functional theory (DFT) with both gradient-corrected and hybrid functionals. For excited state calculations we primarily use time-dependent density functional theory (TD-DFT) with long-range corrected functionals. For finite temperature calculations we primarily use Born-Oppenheimer molecular dynamics (BOMD). ******Ligand-passivated semiconductor nanocrystals (NCs), also called quantum dots, have applications in many areas including photovoltaic devices. Upon adsorption of a photon with energy greater than the band gap, an electron-hole pair is formed and, if it can be separated, an electric current can be generated. Due to quantum confinement, a smaller NC has a larger band gap which can make better use of higher energy photons. Our current focus is on CdSe nanocrystals and related structures in which Se is replaced by Te or Cd is replaced by Cu2. Gold nanostructures have properties which are very different from those of the bulk metal. We established the stability of helical gold nanorods (both bare and with adsorbed molecules) and compared them to alternative compact and cage structures. Our current focus is on the optoelectronic properties of helical gold nanorods and their chiral applications as catalysts and biosensors. For toxic metals in the environment, our current focus is on arsenic. Arsenic exists in both inorganic and organic forms that can be interconverted by biogeochemical processes. Less is known about the organic forms and the ways in which they bind to inorganic soil particles. We are examining the properties of organic arsenic and iron-(oxyhydr) oxide complexes, and organic arsenic on goethite surfaces.******Reactivity and bonding are at the heart of chemistry and, although measures such as the Laplacian of the electron density and the electron localization function have been established, other measures could provide important new insights. In this regard, we plan to examine the quantum potential, which is a direct functional of the electron density, ?. In the Kohn-Sham formulation of DFT, the kinetic energy is obtained accurately (via N one-electron orbitals) as an indirect functional of ? but the scaling is nonlinear. We plan to construct an accurate direct (orbital-free) kinetic energy functional.**

在计算方面，我的研究计划试图建模，从而了解（i）半导体纳米晶体，（ii）金纳米结构和（iii）有毒金属的特性。从理论方面来说，我的研究计划试图（i）研究量子电位作为反应性和键合的度量，以及（ii）获得电子密度直接功能的动能的精确表达。对于基态计算，我们主要使用与梯度校正和混合功能的密度功能理论（DFT）的Kohn-Sham公式。对于激发态计算，我们主要将时间依赖性密度功能理论（TD-DFT）与远程校正功能一起使用。对于有限的温度计算，我们主要使用未脑的分子动力学（BOMD）。 ******配体支持的半导体纳米晶体（NCS），也称为量子点，在包括光伏设备在内的许多领域都有应用。在能量大于带隙的光子吸附后，形成电子孔对，如果可以分开，则可以产生电流。由于量子限制，较小的NC具有较大的带隙，可以更好地利用更高的能量光子。我们目前的重点是CDSE纳米晶体和相关结构，其中SE被TE或CD取代的结构被CU2取代。金纳米结构的性质与散装金属的特性大不相同。我们确定了螺旋金纳米棒（裸露和吸附分子）的稳定性，并将其与替代紧凑和笼子结构进行了比较。我们目前的重点是螺旋金纳米棒的光电特性及其作为催化剂和生物传感器的手性应用。对于环境中的有毒金属，我们目前的重点是砷。砷以无机形式和有机形式存在，可以通过生物地球化学过程互换。关于有机形式及其与无机土壤颗粒结合的方式知之甚少。我们正在研究有机砷和铁（Oxyhydr）氧化物配合物的特性，以及在谷座表面上的有机砷。******的反应性和粘合性是化学的核心，尽管诸如电子密度和电子定位功能之类的措施已经建立了重要的措施，但已建立了重要的新iNSUENS，但具有新的量度。在这方面，我们计划检查量子电位，这是电子密度的直接功能，？。在DFT的Kohn-Sham公式中，可以准确获得动能（通过N单电子轨道）作为间接功能？但是缩放是非线性的。我们计划构建准确的直接（无轨道）动能功能。**