Enhancement of thermoelectric performance by synergistic effects from multiple dopings in complex oxides

该奖项由2009年美国复苏和再投资法案(公共法律111-5)资助。研究和教育计划的重点是了解和操纵纳米结构复合氧化物材料中的能量传输现象，以及在能量转换过程方面对包括研究生、本科生和K-12学生在内的广泛范围的学生进行教育。研究包括：(1)受限氧化物结构中的能量输运现象；(2)氧缺乏、杂质掺杂的纳米氧化物材料中的热输运；以及(3)多掺杂对热电应用中电子和声子输运的影响。此外，拟议的教育和推广计划将：(5)教育研究生和本科生以及K-12学生和教师关于用于能量转换的纳米和微型热物理现象；(6)招募少数民族和妇女学习工程学科并进入研究生院。智力价值：利用热电设备将废热转化为电能的显著改进取决于同时降低热电材料的导热系数和提高导电性。最近，几位研究人员提出，抑制声子热导在改善热电材料性能方面非常有效，因为这会影响热输运，但对电子输运性质的影响往往很小。然而，目前使用最先进的碲化铋合金的努力并没有提供足够的空间来大幅降低导热系数，这是因为这些材料本身的导热系数很低。在这方面，探索过去没有得到广泛考虑的材料，如复杂氧化物，是及时和重要的。这些氧化物的电和热传输特性可以用各种方法改变，这为开发新的、高性能的热电材料提供了机会。例如，同时使用属性调整方法可能会产生协同效应，从而显著提高热电性能。从这项研究中获得的知识将促进对能量载体通过受限结构传输的基本理解，并将提供一种方法来定制许多不同材料的特性。我们将通过一系列实验和理论/计算计算来了解载流子输运，这些实验和计算可以作为一个平台来识别其他有希望用于热电应用的复合氧化物。更广泛的影响：高效热电材料有可能从废热中产生大量电力，同时减少温室气体排放。这项研究将被整合到研究生课程和核心本科课程中，并将成为纳米科学相关课程和研讨会的陈述基础，以及通过各种教育计划(包括德克萨斯农工大学的丰富工程经验(E3)计划)向K-12学生和教师推广。访问德克萨斯州的少数民族学校和K-12学校将鼓励女性和代表性不足的群体在各种工程学科中攻读本科生和研究生课程。

0854467YuThis award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).The research and education plan centers on understanding and manipulating energy transport phenomena within nanostructured complex oxide materials, as well as educating a broad spectrum of students including graduate, undergraduate, and K-12 students in aspects of energy conversion processes. The research includes investigation of: (1) energy transport phenomena through confined oxide structures; (2) thermal transport in oxygen-deficient, impurity-doped nanostructured oxide materials; and (3) influence of multiple dopants on electron and phonon transport for thermoelectric applications. In addition, the proposed education and outreach program will: (5) educate graduate and undergraduate students, as well as K-12 students and teachers in nano- and micro-scale thermophysical phenomena for energy conversion; and (6) recruit minorities and women to study engineering disciplines and enroll in graduate schools.Intellectual Merit: Significant improvement in conversion of waste heat to electricity using thermoelectric devices hinges upon the simultaneous reduction of thermal conductivity and enhancement of electric conductivity of thermoelectric materials. Recently, several researchers have suggested that the suppression of phonon thermal conductivity is very effective in improving the performance of thermoelectric materials, as this influences thermal transport but often has a minimal influence on electronic transport properties. However, current efforts using state-of-the-art bismuth telluride alloys do not provide sufficient room to obtain a large reduction in thermal conductivity due to the intrinsically low thermal conductivity of these materials. In this regard, it is timely and important to explore materials that have not been considered extensively in the past, such as complex oxides. The electrical and thermal transport properties of these oxides can be altered using various methods, which provides an opportunity to develop new, high-performance thermoelectric materials. For example, the simultaneous use of property tuning methods might produce synergistic effects that will dramatically increase thermoelectric performance. The knowledge gained from this research will advance the fundamental understanding of energy carrier transport through confined structures and will provide a methodology to tailor the properties of many different materials. The understanding of energy-carrier transport will be obtained through a series of experiments and theoretical /computational calculations, that can be used as a platform to identify other promising complex oxides for thermoelectric applications. Broader Impacts: Highly efficient thermoelectric materials have the potential to generate large amounts of electric power from waste heat, while simultaneously reducing greenhouse gas emissions. The research will be integrated into a graduate course as well as core undergraduate courses, and will form the basis for presentations in nanoscience-related courses and seminars, as well as for outreach to K-12 students and teachers through various education programs including the Enrichment Experiences in Engineering (E3) program at Texas A&M University. Visits to minority and K-12 schools in Texas will encourage women and underrepresented groups to pursue undergraduate and graduate studies in various engineering disciplines.