Beyond Single-Molecule Conductance: Understanding and Controlling Charge Transport by External Stimuli and Supramolecular Interactions

本项目由材料研究学部电子与光子材料项目（EPM）和化学学部化学结构、动力学与机理项目A和B （CSDM-A和CSDM-B）共同资助。非技术描述：电子器件小型化的驱动力不仅推动了对新的有机和无机（宏观）分子材料的探索，而且还刺激了研究以单分子为活性元件的电路所需工具的开发。过去大多数关于制造分子尺度电子器件的研究都集中在分子结构对器件性能的影响上。这个项目超越了这些研究，通过开发方法来利用分子器件周围的环境来控制和调节电子特性。该项目有助于实现功能分子器件，并扩大了在单分子水平上研究和控制电荷输运的实验方法库。这些活动的一个组成部分包括向初高中和本科学生介绍跨学科的科学，包括物理、化学和工程，以灌输追求科学事业的愿望。两所pi的实验室是连接在一起的，这样K-12学校的学生就可以亲身体验哥伦比亚大学跨学科研究环境的生活。技术描述：迫切需要了解和利用分子连接点周围的环境来控制电荷转移特性，并能够创建功能分子尺度的电路元件类似物。过去在分子水平上对传输的大多数研究都集中在电导与分子结构的关系上，而在很大程度上忽略了结周围直接环境的影响。本项目旨在利用分子环境作为外部刺激，利用静电、电化学和超分子相互作用来控制和改变单分子器件的电子特性。该项目的目标有两个：(1)了解环境对分子结传导特性的影响；(2)以可控的方式设计和测量对环境作出反应的材料。这个跨学科的研究项目超越了研究分子连接的基本组成部分——接触、分子和电极——以建立对连接与环境之间界面的理解。它使用基于扫描隧道显微镜的断结技术来研究溶剂/封装剂效应、氧化还原响应系统和大量单分子器件中的超分子相互作用。

This project is jointly funded by the Electronic and Photonic Materials Program (EPM) in the Division of Materials Research (DMR) and by the Chemical Structure, Dynamics and Mechanisms Programs A and B (CSDM-A and CSDM-B) in the Division of Chemistry (CHE).Nontechnical Description: The drive to miniaturize electronics has not only motivated the search for new organic and inorganic (macro)molecular materials, but has also spurred the development of tools required for studying circuits with single molecules as active elements. Most past research on creating molecular-scale electronic devices has focused on the impact of molecular structure on the device properties. This project goes beyond such studies by developing methods to exploit the environment around molecular devices in order to control and modulate electronic characteristics. The project contributes to the realization of functional molecular devices as well as expansion of an arsenal of experimental methods to study and control charge transport at the single-molecule level. An integral part of the activities include the introduction of interdisciplinary science bridging physics, chemistry and engineering to middle-school, high-school, and undergraduate students, in order to instill a desire to pursue careers in science. Both PIs' laboratories are bridged thus K-12 school students can experience, first-hand, life in interdisciplinary research environment at Columbia University.Technical Description: There is a strong need to understand and use the environment around molecular junctions to control charge transfer characteristics and enable creating functional molecular-scale analogs of circuit elements. Most past research efforts on transport at the molecular level have focused on correlating conductance to molecular structure, while the impact of the immediate environment around the junction has largely been ignored. This project aims to use the molecular environment as an external stimulus to control and alter the electronic characteristics of single-molecule devices, exploiting electrostatic, electrochemical and supramolecular interactions. The goals of this project are two-fold: (1) to understand the effects of the environment on the conduction properties of molecular junctions; and (2) to design and measure materials that respond to the environment in a controlled manner. This interdisciplinary research project goes beyond studying the fundamental components in molecular junctions - contacts, molecules, and electrodes - to establish an understanding of the interface between the junctions and the environment. It uses the scanning tunneling microscope based break-junction technique to study solvent/encapsulant effects, redox responsive systems, and supramolecular interactions in a large number of single-molecule devices.