Chemical and Nanoengineering Regulation of Inter-molecular Electron Transport in Organic Semiconductor Thin Films

技术摘要：该研究计划由固态和材料化学计划支持，旨在使用含有π共轭分子（如基于低聚噻吩的有机薄膜）的特别设计的模型装置，在分子水平上理解分子间电子传输的化学调制。 为了避免表面粗糙度的影响，将制造具有亚纳米粗糙度的超平纳米电极（UNE），使用基于原子力显微镜（AFM）的纳米接枝方法将设计的分子放置在其上。 多功能原子力显微镜使原位纳米光刻，高分辨率的结构表征，并测量电子传输。有机薄膜的化学和电子性质将通过改变其头部基团、分子间相互作用和末端基团来控制。 将研究暴露于化学物质期间和之后的电子性质的响应，与原位结构相关。 该项目结合了纳米光刻和成像（PI），UNE制造和电子传输（co-PI）以及有机合成（合作者）的技术实力。 随着UNE分子水平结构和堆积的精确设计，分子间电子传递的系统研究变得可行和可靠。 这一系统的调查将审查与膜形态的分子间运输的相关性，揭示结构的作用，特别是域边界和分子水平的包装，并检查分析物结合到膜末端的影响。 非技术总结：该研究旨在精确测量电子器件模型结内分子之间和分子之间的电子传输沿着。 这些测量在技术上非常具有挑战性，但对于实现现代分子电子器件的巨大潜力至关重要，现代分子电子器件比最先进的晶体管更小，其特性可通过改变分子的结构和包装来调节。 研究小组计划充分利用当今的技术，制造具有亚纳米粗糙度的超平微电极，高精度定位分子的能力，以及测量这些精心设计的结上的电子传输。 这一调查应产生可靠的和基本的信息，了解有机半导体为基础的设备，并指导下一代分子器件的设计。 这项研究是高度跨学科的，需要Liu（AFM纳米加工和高分辨率成像），Salmeron（UNE制造和器件表征）和Schore（有机半导体材料合成）之间的密切合作，其团队成员将获得微/纳米加工，分子分辨率成像，有限空间中的电子运动和器件制造方面的高级培训。 该团队一直与当地社区学院的教师（米勒，萨克城学院）和学生密切合作，让他们接触到这些模型设备的概念和实验。在西班牙语和英语语言非常精通，萨尔梅龙已经参加，并将继续参加西班牙裔广播节目，以吸引西班牙裔学生到现代设备和材料科学的前沿。

TECHNICAL SUMMARY:This research program, supported by the Solid State and Materials Chemistry Program, aims at a molecular level understanding of chemical modulation of intermolecular electron transport using a specially designed model device containing pi-conjugated molecules such as oligothiophene based organic thin films. To circumvent contribution from surface roughness, Ultraflat NanoElectrodes (UNEs) with sub-nanometer roughness will be fabricated, onto which designed molecules will be placed using atomic force microscopy (AFM) based nanografting method. The multifunctional AFM enables in situ nanolithography, high-resolution structural characterization, and measurements of electron transport. The chemical and electronic properties of organic films will be controlled by varying their head group, intermolecular interactions and terminal group. The response of the electronic properties during and after exposure to chemical species will be studied, in correlation to structure in situ. The project combines the technical strength of nanolithography and imaging (PI), UNE fabrication and electron transport (co-PI), and organic synthesis (collaborator). With molecular level structure and packing engineered precisely on UNEs, the systematic investigation of intermolecular electron transport becomes feasible and reliable. This systematic investigation will review the correlation of intermolecular transport with the film morphology, reveal the role of structure, especially domain boundaries and molecular level packing, and examine the influence of analytes binding to the film termini. NON-TECHNICAL SUMMARY:The research aims at accurate measurements of electron transport along and in between molecules within model junctions of electronic devices. These measurements are technically very challenging, yet critical in order to realize the great potential of modern molecular electronic devices, which are smaller than state-of-the-art transistors, with properties tunable by varying the structure and packing of the molecules. The research team plans to take best advantage of today's technology, fabrication of ultraflat microelectrodes with sub-nanometer roughness, the ability to position molecules with high precision, and measurements of electron transport over these well-engineered junctions. This investigation should yield reliable and fundamental information in understanding organic semiconductor based devices, and guiding design of a next generation of molecular devices. The investigation is highly interdisciplinary, and requires close collaboration among Liu (AFM nanofabrication and high resolution imaging), Salmeron (UNE fabrication and device characterization), and Schore (synthesis of organic semiconductor materials), whose team members will attain advanced training in micro/nanofabrication, molecular resolution imaging, electron movement in confined space, and device making. The team has been working closely with local community college faculty (Miller, SacCity College) and students to expose them to the concept and experiments of these model devices. Being extremely proficient in both Spanish and English languages, Salmeron has participated and will continue to participate in Hispanic Radio Shows to attract Hispanic students to the forefront of modern devices and materials science.