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Polaron and Spin Transport in Nanoscale Molecular Junctions

纳米级分子结中的极化子和自旋输运

基本信息

批准号：
1708173
负责人：
Daniel Frisbie
金额：
$ 45万
依托单位：
University of Minnesota-Twin Cities
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-08-01 至 2020-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1708173&HistoricalAwards=false
关键词：
Polaron Spin Transport Nanoscale Molecular

项目摘要

This award is funded by the Macromolecular, Supramolecular and Nanochemistry Program in the Division of Chemistry. Professor C. Daniel Frisbie of the University of Minnesota-Twin Cities is supported to develops techniques both for making ultrathin films (1-10 nm, a tiny fraction of a human hair in width) of organic semiconductors and for sensitively measuring their conduction properties using an atomic force microscope (AFM). The organic films are made in such a way that molecular orientation is precisely controlled so that electrical conduction is measured in the most favorable direction. These methods advance the frontiers of organic semiconductor science that underpin display technology by providing new knowledge about how charges move in oriented molecules. Organic semiconductors belong to a new class of functional molecular materials that have achieved widespread commercial success in organic light emitting devices (OLEDs) employed in smart phone displays and televisions. Understanding the electrical conduction properties of these molecular semiconductors on microscopic "even nanoscopic" length scales is vital to their continued improvement. Integrating the research with education provides research opportunities for graduate students and postdoctoral researchers, training them to be the next generation of experts in molecular synthesis and characterization, electrical conductance measurements, and nanotechnology. The plan leverages unique experimental approaches developed by the PI and his students over the last 15 years including (i) conducting probe atomic force microscopy (CP-AFM) for forming metal-molecule-metal junctions and (ii) oligoimine click chemistry for building surface-anchored pi-conjugated wires with monomer-by-monomer control over chain architecture. There are four project goals: (1) to use isotopic labeling to understand the nature of polarons and polaron hopping transition states in pi-conjugated molecular wires; (2) to investigate polaron size effects on hopping transport; (3) to measure spin transport as a function of both molecular wire length and tailored architecture using CP-AFM spin valve junctions with ferromagnetic (FM) contacts; (4) to demonstrate electronic structure control and current switching. The team collaborates with two quantum chemistry groups that provide theoretical and computational support for the project. Overall, the research plan balances lower risk experiments that are certain to yield important results with higher risk ideas that open up new directions.

该奖项由化学学部的大分子、超分子和纳米化学项目资助。明尼苏达大学双城分校的c·丹尼尔·弗里斯比教授得到支持，开发了制作有机半导体超薄薄膜（1-10纳米，人类头发宽度的一小部分）和使用原子力显微镜（AFM）灵敏测量其传导特性的技术。有机薄膜是这样制作的：分子取向被精确地控制，从而在最有利的方向上测量电导率。这些方法通过提供关于电荷如何在定向分子中移动的新知识，推动了有机半导体科学的前沿，从而支撑了显示技术。有机半导体是一类新型的功能分子材料，在智能手机显示屏和电视中使用的有机发光器件（oled）中取得了广泛的商业成功。了解这些分子半导体在微观甚至纳米尺度上的导电特性对它们的持续改进至关重要。将研究与教育相结合，为研究生和博士后研究人员提供了研究机会，培养他们成为分子合成和表征、电导测量和纳米技术方面的下一代专家。该计划利用了PI和他的学生在过去15年中开发的独特实验方法，包括(i)导电探针原子力显微镜（CP-AFM）用于形成金属-分子-金属结，（ii）低聚亚胺点击化学用于构建表面锚定的PI -共轭导线，通过单体对链结构的控制。项目目标有四个：(1)利用同位素标记了解π共轭分子线中极化子和极化子跳跃迁态的性质；(2)研究极化子尺寸对跳跃输运的影响；(3)利用带有铁磁（FM）触点的CP-AFM自旋阀结测量自旋输运作为分子线长度和定制结构的函数；(4)演示电子结构控制和电流开关。该团队与两个量子化学小组合作，为该项目提供理论和计算支持。总体而言，研究计划平衡了一定会产生重要结果的低风险实验与开辟新方向的高风险想法。