Imaging charge transfer dynamics in nanomaterials using electron donor/acceptor modified AFM tips

该奖项由化学学部化学测量与成像项目资助，将支持埃默里大学的连天全教授及其博士后、研究生和本科生研究人员利用特殊修饰的原子力显微镜（AFM）尖端研究纳米材料中电荷转移动力学成像的可行性。廉教授和他的研究小组将把量子点连接到原子力显微镜尖端，并测量修饰后的尖端与探针表面之间的光致电荷转移。这项研究的目的是为了更好地理解用于太阳能转换的纳米材料在边界处发生的光物理过程。原子力显微镜方法利用纳米探针和表面之间的接触来测量被探针表面形貌的变化。探针能够在纳米（或更小）长度尺度上测量下垫表面的物理性质（例如硬度，柔软度）的差异。廉教授和他的团队正在尝试建造一种AFM探针，除了测量修饰探针尖端和底层表面之间光诱导电荷转移率的差异外，它将能够做AFM的工作。目标是发展以与AFM方法相同的分辨率测量纳米级材料的光物理/电学性质的能力。参与该项目的学生将获得开发尖端分析光谱工具的有用经验，这些工具将有助于评估和表征技术上有用的材料。作为这项工作的一部分，廉教授将继续他的模范努力，鼓励来自代表性不足群体的学生从事科学事业。

In this award, funded by the Chemical Measurement and Imaging Program of the Division of Chemistry, Professor Tianquan Lian of Emory University and his postdoctoral, graduate and undergraduate student researchers will be supported to investigate the feasibility of imaging charge transfer dynamics in nanomaterials using specially modified atomic force microscopy (AFM) tips. Prof. Lian and his research group will attach quantum dots to the AFM tips and will measure the photoinduced charge transfer between the modified tip and the probed surface. The goal of this research is to develop a better understanding of the photophysical process taking place at the boundaries in nanomaterials used in solar energy conversion.Atomic force microscopy methods use contact between a nanometer-scale probe and a surface to measure the changes in morphology of the probed surface. The probe is able to measure differences in the physical properties (e.g. hardness, softness) of the underlying surface at the nanometer (or smaller) length scale. Prof. Lian and his group are attempting to build an AFM probe that will be able to do what the AFM does, except by measuring differences in the rate of photoinduced charge transfer between the modified probe tip and the underlying surface. The goal is to develop the ability to measure the photophysical/electrical properties of nanoscale materials with the same resolution that can be obtained with AFM methods. The students working on this project will gain useful experience in developing cutting-edge analytical spectroscopy tools that will be useful for evaluating and characterizing technologically useful materials. As part of this work, Prof. Lian will continue his exemplary efforts at encouraging students from underrepresented groups to pursue careers in the sciences.