Monitoring the Evolution of Molecular Structure in Transistors by Interfacial Spectroscopy

技术描述：该项目使用特定于界面的振动和频率产生光谱来研究有机场效应晶体管中的分子振动及其在有源界面的取向。这项工作的一个基本任务是通过光谱监测操作设备中界面的演变，以深入了解界面分子结构和功能之间的关系。这些活动确定了在介电界面上浇注溶剂和界面偶极子在提高薄膜晶体管的电性能方面的作用。该项目还探索了磷酸锆自组装纳米介电材料在界面有机结构上的应用。此外，研究小组使用多路和频光谱来测量介电和有机半导体层在热退火过程中分子结构和载流子积累的时间演变。这些实验的现场性质为从功能设备内部的材料响应提供了一个新的视角，不仅有可能描述什么变化，而且有可能描述结构变化的时间尺度是什么，以及这些特性如何与宏观的电响应相关。非技术描述：晶体管是从手机到杂货店结账扫描仪的每一种数字设备的基本构建块之一。在运行过程中，电流沿界面移动，该区域中原子或分子的排列决定了电荷流动的效率。该项目使用专门的光学测量来确定这些设备中的分子在微观层面上是如何排序的，以及它们对底层表面的化学成分和热处理的反应如何。该项目是跨学科的，培养出在材料加工、电气和光学表征技术方面熟练的下一代科学家。此外，作为草原大学项目的一部分，研究团队每年夏天都会组织和指导为期三天的农村外展活动，在那里，他们使用动手演示，在初中年龄的参与者观察到的材料特性和他们熟悉的现实世界技术之间建立联系。

Technical Description: This project uses interface-specific vibrational sum frequency generation spectroscopy to study molecular vibrations and their orientations at the active interface in organic field-effect transistors. An underlying mission of this work is to spectroscopically monitor the evolution of the interface in operational devices to gain insight into the relationships between interfacial molecular structure and function. The activities establish the role of casting solvents and interfacial dipoles at the dielectric interface in enhancing the electrical performance of thin film transistors. The project also explores the use of zirconium phosphonate self-assembled nanodielectrics on the interfacial organic structure. In addition, the research team uses multiplexed sum frequency spectroscopy to measure the temporal evolution of molecular structures and carrier accumulation in the dielectric and organic semiconductor layers during thermal annealing. The in-situ-nature of these experiments provides a new perspective on the materials response from inside the functioning device, with the potential to describe not only what changes, but also what the timescales of structural change are and how these properties relate back to the macroscopic electrical response.Non-Technical Description: Transistors are one of the basic building blocks of every digital device, from cell phones to grocery store check-out scanners. During operation, electricity moves along an interface and the arrangement of atoms or molecules in this region determines how efficiently the charges can flow. This project uses specialized optical measurements to determine how the molecules in these devices are ordered at the microscopic level, and how they respond to the chemistry of the underlying surfaces and to thermal processing treatments. The project is interdisciplinary, producing next-generation scientists who are skilled in materials processing, and electrical and optical characterization techniques. In addition, the research team organizes and directs a three-day-long rural outreach event each summer as a part of the University on the Prairie program where they use hands-on demonstrations to make connections between the materials properties observed by the junior high school aged participants and the real-world technologies with which they are familiar.