Microscopic Electronic Heterogeneity Studied with Ultrafast 2D Microscopy

使用超快二维显微镜研究微观电子异质性

• 批准号: 2314378
• 负责人: Martin Zanni
• 金额: $ 56.5万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-01 至 2026-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2314378&HistoricalAwards=false
• 关键词: Microscopic; Electronic; Heterogeneity; Studied; Ultrafast

With support from the Chemical Structure, Dynamics, and Mechanisms-A (CSDM-A) program in the Division of Chemistry, Professor Martin Zanni of the University of Wisconsin-Madison is developing a spatially resolved two-dimensional white-light microscope to study charge and exciton transport in perovskite microcrystals and heterogeneous thin films of semiconducting carbon nanotubes. The goal is to measure and understand the dependence of exciton and charge diffusion on microscopic heterogeneities in structural geometries and electronic couplings. These properties are important because they impact the timescale and length scales over which energy and charge moves through the material. Professor Zanni and his students will design and construct a 2D White-Light microscope in which the focus of the pump beam can be raster scanned relative to the probe. The corresponding images will give spatial maps that correlate electronic heterogeneity to exciton and charge diffusion timescales and lengths. Their studies will create a new type of hyperspectral imaging technique for ultrafast 2D spectroscopy and could lead to a better understanding of the fundamental science that links electronic structure and exciton/charge diffusion to nano-and micro-scale heterogeneities. Professor Zanni and his students funded by this grant will be involved in outreach to a local elementary school as well as build and test a novel design for an ergonomic and wheelchair accessible laser table. The electronic structure of organic and inorganic films and crystals dictates the timescale and length of exciton and charge diffusion. Inherent to solution processed materials are micro- and nanoscale heterogeneities that alter electronic structure. Using a new microscope built from an ultrafast 2D white-light spectrometer, the Zanni research group discovered spatial patterns of microscopic heterogeneities in electronic structure within single microcrystals across a variety of materials. In two different types of singlet fission materials, changes were observed in bandgap near edges, defects, and in appreciable quantities throughout the bulk material. In 2D perovskites, micron spatial variations in the binding energy of biexcitons were observed. With these observations in mind, it stands to reason that a crystal that has spatially heterogeneous electronic structure should also have spatially dependent exciton diffusion. The purpose of this proposal is to test that hypothesis by studying the link between electronic heterogeneity and exciton/charge diffusion on the micron length scale within microcrystals and domains of thin films. To do so, a new version of the 2D White-Light microscope will be built in which the focus of the pump beam can be raster scanned relative to the probe. Using this new microscope, the ultrafast dynamics in singlet fission and 2D perovskite microcrystals will be measured as will purposely engineered thin films of semiconducting carbon nanotubes. The images will give spatial maps that correlate electronic heterogeneity to exciton and charge diffusion lengths. By building a new type of ultrafast microscope and pursuing the aims of this proposal, the Zanni team aims to build a better understanding of how exciton and charge diffusion is dictated by heterogeneity in electronic structure on sub-crystallin and sub-domain length scales.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.

在化学结构，动力学和机制-A（CSDM-A）计划中的支持下，威斯康星大学麦迪逊分校的马丁·扎尼教授正在开发一种空间分辨的二维白光显微镜，以研究Perovskite Microcrystals和Nyobob semibot of SemiciConcots of Semicicecons of Semicicecons of Semicicecons of SemiceConds of SemiceConds of Semicicsss of Semicicsss of Semicicsssssssssssssssssssssssssssssssssssssssssssssss。目的是测量和理解激子和电荷扩散对结构几何和电子耦合中微观异质性的依赖性。这些特性很重要，因为它们会影响能量和电荷在材料中移动的时间尺度和长度尺度。 Zanni教授和他的学生将设计和构建一个2D白光显微镜，其中可以相对于探针扫描泵束的焦点。相应的图像将给出将电子异质性与激子和电荷扩散时间尺度和长度相关的空间图。他们的研究将创建一种用于超快2D光谱法的新型高光谱成像技术，并可以更好地理解将电子结构和激子/电荷扩散与纳米和微观异质性联系起来的基础科学。 Zanni教授及其由这笔赠款资助的学生将参与与当地小学的宣传，并为符合人体工程学和轮椅可访问的激光桌建立和测试新颖的设计。有机和无机膜和晶体的电子结构决定了激子的时间尺度和长度和电荷扩散。溶液加工材料固有的是改变电子结构的微观和纳米级异质性。 Zanni Research Group使用了由超快2D白光光谱仪构建的新显微镜，发现了各种材料中单个微晶体内的电子结构中显微镜异质性的空间模式。在两种不同类型的单线裂变材料中，在整个大量材料的边缘，缺陷和可观数量的带隙中观察到变化。在2D钙钛矿中，观察到Biexcitons结合能中的微米空间变化。考虑到这些观察，可以理解具有空间异质电子结构的晶体也应具有空间依赖的激子扩散。该提案的目的是通过研究电子异质性与激子/电荷扩散之间在微晶和薄膜的域内的微米长度尺度上的链接之间的联系来检验假设。为此，将构建一个新版本的2D白光显微镜，其中可以相对于探针扫描泵束的焦点。使用这种新的显微镜，将测量单重裂变和2D钙钛矿微晶中的超快动力学，并有意地设计了半导体碳纳米管的薄膜。这些图像将给出将电子异质性与激子和电荷扩散长度相关的空间图。通过建立一种新型的超快显微镜并追求该提议的目的，Zanni团队旨在更好地理解对激子和电荷扩散的方式，这取决于在电子结构中的异质性在亚晶格蛋白和子层长度范围内的电子结构中的异质性决定。这一奖项反映了NSF的法定任务和范围的范围，这是通过评估的范围来构成的，并在范围内构成了Interveriation的支持。