CAREER: Structure-Property Relationships of Nanocrystalline Oxide Films for Gas Sensors

9875405 pan对可靠的化学传感器的研究和开发与对各种燃烧过程的空气污染和燃料燃烧效率的高度控制的需求并行，并且越来越关注家庭和涉及易燃和有毒气体的工业活动的安全。开发灵敏、选择性和耐用的气体传感器的主要障碍之一是缺乏对这些设备操作所涉及的基本过程以及这些过程与传感材料的微观结构和组成之间关系的充分了解。该学院早期职业发展项目将重点关注纳米晶体氧化锡材料，这是一种用作化学传感器的模型系统，以获得对结构-性能关系的基本理解。计划进行系统的实验研究：(1)在高温气体环境下反应过程中的微观结构不稳定性和晶体缺陷（如晶体剪切面、晶界和掺杂物）演变；(2)单个缺陷（晶体剪切面、孪晶界和特殊晶界）和界面的原子结构和电子特性；(3)高温下不同气体环境的显微结构、形貌和化学成分信息与电测量的相关性。纳米氧化锡薄膜的研究将通过空间分辨显微镜和光谱技术结合各种模拟气体环境中的阻抗测量进行。具体来说，这种先进的显微镜技术将与使用特殊设计的设备对样品进行热化学预处理相结合，该设备模拟气体传感器在使用中遇到的环境。通过研究项目的过程中，PI计划探索商业软件模拟程序，用于学生在晶体物理学的教育和培训。此外，将建立一个虚拟显微镜数据库，可通过网络访问，用于图像、晶体结构渲染图和演示现场电子显微镜观察的视频剪辑/片段。开发灵敏、选择性和耐用的气体传感器的主要障碍之一是缺乏对这些设备操作所涉及的基本过程以及这些过程与传感材料的微观结构和组成之间关系的充分了解。这项关于氧化锡（一种气体传感模型材料）的结构和化学的教师早期职业发展项目的结果将用于解释该材料的电学性质和传感性能，并将为如何定制具有优化微观结构和理想传感性能的固态化学传感器提供指导。所提出的研究涉及许多先进工具的利用和开发，如图像模拟，结构建模和电子显微镜。该教育计划的长期目标是发展非传统和创新的教学技术，为毕业生提供在现代科学和工程领域取得成功所需的智力、创造性和科学理解。这些方法旨在确保学生为未来的科学和工业环境做好充分的准备。

9875405PanThe research and development of reliable chemical sensors parallels the demand for a high degree of control over air pollution and fuel combustion efficiency for a variety of combustion processes, and increasing concern over safety in homes and in industrial activities involving flammable and poisonous gases. One of the main obstacles in the development of sensitive, selective and durable gas sensors has been the lack of adequate understanding of the fundamental processes involved in the operation of these devices and the relationships between these processes and the microstructure and composition of the sensing materials. This Faculty Early CAREER Development project will focus on nanocrystalline tin oxide materials, a model system for use as chemical sensors, to obtain fundamental understanding of the structure-property relationships. Systematic experiments are planned to investigate: (1) microstructural instabilities and crystal defect (e.g., crystallographic shear planes, grain boundaries, and dopants) evolution during the reaction process in the gaseous environment at elevated temperatures; (2) the atomic structure and electronic characteristics of individual defects (crystallographic shear planes, twin boundaries, and special grain boundaries) and interfaces; (3) correlation of microstructure, morphology, and chemical composition information with electrical measurements in different gaseous atmospheres at elevated temperatures. The studies on nanocrystalline tin oxide films will be conducted by spatially resolved microscopy and spectroscopy techniques in combination with impedance measurements within various simulated gaseous environments. Specifically, such advanced microscopy techniques will be combined with the thermal and chemical pre-treatment of specimens using a specially designed apparatus which simulates the environment the gas sensors encounter in use. Through the course of the research project the PI plans to explore the commercial software simulation programs for use in students education and training in crystal physics. In addition, a virtual microscopy database will be established, accessible via the Web, for images, renderings of crystal structures, and video clips/segments demonstrating the in-situ electron microscope observations. One of the main obstacles in the development of sensitive, selective and durable gas sensors has been the lack of adequate understanding of the fundamental processes involved in the operation of these devices and the relationships between these processes and the microstructure and composition of the sensing materials. The results from this Faculty Early CAREER Development project about the structure and chemistry of tin oxide, a model gas sensing material, will be used to interpret the electrical properties and sensing performance of that material and will provide guidance on how to tailor solid state chemical sensors, which have optimized microstructure and desirable sensing properties. The proposed research involves the utilization and development of a number of advanced tools, such as image simulations, structural modeling, and electron microscopy. The long-term goal of the educational plan is to develop non-traditional and innovative pedagogical techniques that will provide graduates with the intellectual, creative, and scientific understanding needed to prosper in the modern scientific and engineering fields. These approaches are aimed to ensure that the students are adequately prepared for the scientific and industrial environment of the future.