Charge Transfer as a Probe of the Permeability of Organic Adlayers on Colloidal Semiconductor Quantum Dots

电荷转移作为胶体半导体量子点上有机吸附层渗透性的探针

• 批准号: 1400596
• 负责人: Emily Weiss
• 金额: $ 36.16万
• 依托单位: Northwestern University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-01 至 2017-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1400596&HistoricalAwards=false
• 关键词: Charge; Transfer; Probe; Permeability; Organic

In research funded by the Macromolecular, Supramolecular and Nanochemistry Program, Emily Weiss of Northwestern University is carrying out research to find ways to coat small objects known as nanoparticles with organic substances so that they can be converted into more useful materials. Nanoparticles composed of metal or semiconductor substances find application in a variety of technologies, including energy, the medical field, and in chemical and biological sensors. The surfaces of these very small particles are inherently unstable, though, so to make them more useful they must typically be coated with a layer of organic molecules that make the surface chemically and electronically homogeneous. This organic layer also presents a physical barrier that impedes the approach of other molecules and limits their adsorption. The organic layer, therefore, acts like a semi-permeable membrane, protecting the nanoparticle and making it more useful. This research is having a broader impact by helping investigators improve the use of nanoparticles in analytical, therapeutic and energy applications. Potential applications include better means of corrosion resistance, specific detection of chemical and biological substances and new ways to better target drugs to the desired location in the body. The work is having a further broad impact through the involvement in the research of undergraduates and members of groups historically under-represented in science. As part of the project, an undergraduate is also helping to redesign the curriculum for General Chemistry at Northwestern to make it more accessible to all students.This research is developing ways to convert organic-coated nanoparticles (NPs) into functional materials by facilitating the design of surface chemistries that precisely control the types of chemical reactions, redox reactions, and adsorption events that nanoparticles undergo in a variety of environments. To do this, the investigators are finding ways to control 1) the interaction of the NP with proximate molecules of interest while minimizing non-specific or unproductive interactions, and 2) the stability of the organic monolayer in various chemical environments. A specific aim of this research project is to determine the relationship between the chemical composition of organic adlayers on colloidal semiconductor quantum dots (QDs) and the permeability of these adlayers to small molecules, under various environmental conditions, using measurements of interfacial charge transfer (CT) between the QD and molecular redox probes. Chemical functionalization of NPs is the most versatile, precisely tunable method for controlling the reactivity of a NP, because self-assembled monolayers (SAMs) have been shown to act as molecular recognition layers. The intellectual merit of this work is that it quantitatively characterizes the relationship between the chemical structure of the adlayer and its permeability to small molecules, and determines the precision with which we can control QD-molecule interactions through the surface chemistry of the particle. This study explores four properties of the adlayer in tuning its stability and permeability: (i) the binding constant of the native ligands, (ii) the intermolecular order of the native ligand shell, (iii) the charge distribution at the interface between the ligand shell and the solvent, and (iv) the hydrophobicity/oleophobicity of the ligand shell.

在由大分子，超分子和纳米化学计划资助的研究中，西北大学的艾米丽·韦斯（Emily Weiss）正在进行研究，以寻找将称为纳米颗粒的小物体涂上有机物质的小物体，以便它们可以转化为更有用的材料。由金属或半导体物质组成的纳米颗粒在包括能量，医疗领域以及化学和生物传感器在内的各种技术中都有应用。但是，这些非常小的颗粒的表面本质上是不稳定的，因此，为了使它们更有用，通常必须用一层有机分子涂层，这些有机分子在化学上和电子上具有均匀的表面。该有机层还提出了一种物理障碍，阻碍了其他分子的方法并限制了它们的吸附。因此，有机层的作用像半渗透的膜，保护纳米颗粒并使其更有用。这项研究是通过帮助研究人员改善纳米颗粒在分析，治疗和能源应用中的使用，从而产生更广泛的影响。潜在的应用包括更好的耐腐蚀性手段，化学和生物物质的特定检测以及将药物更好地靶向人体所需位置的新方法。这项工作是通过参与本科生的研究和历史上代表科学不足的群体的研究而产生的更广泛的影响。 As part of the project, an undergraduate is also helping to redesign the curriculum for General Chemistry at Northwestern to make it more accessible to all students.This research is developing ways to convert organic-coated nanoparticles (NPs) into functional materials by facilitating the design of surface chemistries that precisely control the types of chemical reactions, redox reactions, and adsorption events that nanoparticles undergo in a variety of environments.为此，研究人员正在寻找控制方法1）NP与感兴趣的近端分子的相互作用，同时最大程度地减少非特异性或非生产性相互作用，以及2）2）有机单层在各种化学环境中的稳定性。该研究项目的一个具体目的是在各种环境条件下，在各种环境条件下，使用QD和分子氧化还原探测器之间的界面电荷转移（CT）测量，在各种环境条件下，有机粘附器在胶体半导体量子点（QD）上的化学成分与这些adlayer剂量对小分子的渗透性之间的关系。 NP的化学功能化是控制NP反应性的最通用，最精确的可调方法，因为自组装单层（SAM）已被证明是分子识别层。这项工作的智力优点在于，它定量地表征了adlayer的化学结构与其对小分子的渗透性之间的关系，并确定我们可以通过粒子的表面化学来控制QD-MOLECULE相互作用的精度。这项研究探讨了adlayer在调整其稳定性和渗透性方面的四个特性：（i）天然配体的结合常数，（ii）天然配体壳的分子间阶，（iii）配体壳体壳和（iiv）的界面界面的电荷分布，以及（IV），以及（IV）。