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

技术概述：该研究项目由固态和材料化学项目支持，旨在通过一个特殊设计的模型装置，包括pi共轭分子，如寡硫吩基有机薄膜，从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，将制作具有亚纳米粗糙度的超平面纳米电极（UNEs），并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可实现原位纳米光刻、高分辨率结构表征和电子传输测量。通过改变薄膜的头基、分子间相互作用和末端基，可以控制薄膜的化学和电子性能。在暴露于化学物质期间和之后的电子性质的响应将被研究，与原位结构的关系。该项目结合了纳米光刻和成像（PI）， UNE制造和电子传输（co-PI）和有机合成（合作者）的技术力量。由于在UNEs上精确地设计了分子水平结构和包装，系统地研究分子间电子传递变得可行和可靠。这项系统的研究将回顾分子间运输与薄膜形态的关系，揭示结构的作用，特别是区域边界和分子水平的包装，并检查分析物与薄膜末端结合的影响。非技术总结：该研究旨在精确测量电子设备模型结内分子间和分子间的电子传输。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，并且可以通过改变分子的结构和包装来调节其性能。研究小组计划充分利用当今的技术，制造亚纳米粗糙度的超平面微电极，高精度定位分子的能力，以及在这些精心设计的结上测量电子传输。这项研究将为理解基于有机半导体的器件提供可靠和基础的信息，并指导下一代分子器件的设计。这项研究是高度跨学科的，需要刘（AFM纳米制造和高分辨率成像）、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，他们的团队成员将获得微/纳米制造、分子分辨率成像、密闭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，安全学院）和学生密切合作，让他们了解这些模型设备的概念和实验。Salmeron精通西班牙语和英语，他参加并将继续参加西班牙广播节目，以吸引西班牙学生关注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.