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

9875405 Pan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以及对涉及易燃和有毒气体的家庭和工业活动中的安全性的日益关注相一致。 开发灵敏、选择性和耐用的气体传感器的主要障碍之一是对这些装置的操作中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的关系缺乏足够的理解。 该学院早期职业发展项目将专注于纳米晶体氧化锡材料，作为化学传感器使用的模型系统，以获得对结构-性能关系的基本理解。 系统的实验计划研究：（1）微观结构不稳定性和晶体缺陷（例如，晶体剪切面、晶界和掺杂剂）在高温气态环境中反应过程中的演化;（2）单个缺陷的原子结构和电子特性（晶体剪切面、孪晶界和特殊晶界）和界面;（3）在高温下不同气体气氛中的微结构、形态和化学成分信息与电学测量的相关性。 纳米氧化锡薄膜的研究将进行空间分辨显微镜和光谱技术结合在各种模拟气体环境中的阻抗测量。 具体而言，这种先进的显微镜技术将结合使用专门设计的装置，模拟气体传感器在使用中遇到的环境的标本的热和化学预处理。 通过研究项目的过程中，PI计划探索商业软件模拟程序，用于学生的教育和晶体物理培训。 此外，还将建立一个虚拟显微镜数据库，可通过网络访问，以获取图像、晶体结构渲染图和演示原位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对这些装置的操作中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的关系缺乏足够的理解。 该学院早期职业发展项目关于氧化锡（一种模型气敏材料）的结构和化学的结果将用于解释该材料的电气特性和传感性能，并将为如何定制固态化学传感器提供指导，该传感器具有优化的微观结构和理想的传感特性。 拟议的研究涉及利用和开发一些先进的工具，如图像模拟，结构建模和电子显微镜。 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蓬勃发展所需的智力，创造力和科学理解。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.