EAGER: Simultaneously Controlling Multi-Scale Material Structures Based on Fluid Layering With Self-Assembly and Eutectic Growth

EARLY概念探索性研究资助（EAGER）项目旨在通过在介观，微米和纳米尺度上操纵其结构来开发高性能块状热电材料。在热电材料的结构中实现宽范围的长度尺度有望使声子散射最大化，这又将由于声子（或晶格）热传导的耗尽而使热电材料的性能最大化。在这里，新的想法是利用连续水平的流体力学（分层技术）设计的介/微米尺度的结构，同时创建自组装和共晶生长的微/纳米尺度的结构。通过用液相前体进行中/微米级分层和结构化，纳米颗粒孕育剂的尺寸和分布将被操纵以控制微米/纳米级的异相成核和固相形成。这种新的开箱即用但高风险的方法将流体力学融入材料科学/工程，将提供新的见解和研究方向。热电能量转换系统提供了一个很好的策略，通过从包括汽车和发电厂在内的各种耗电系统中清除废热来提高我们电力基础的可持续性，或者为计算机和电子设备提供有效的紧凑型冷却，具有鲁棒性和静音性。该研究将为通过改变材料结构来提高其效率提供合理而新颖的方法。此外，研究成果包括通过解决主要障碍之一纳米颗粒聚集来充分利用纳米颗粒的关键知识。这种新的方法结合了连续介质水平的流体力学和控制结构到纳米级相关的材料科学/工程可能会带来后续的研究相关的多尺度结构材料的合理设计。该研究还包括培养具有跨学科合作研究经验的博士生;通过NSF资助的Louis Stokes少数民族参与联盟（Louis Stokes Alliance for Minority Participation at Texas A M University）和增强工程多样性中心（Center for Enhancement of Engineering Diversity at Cubina Tech），扩大代表性不足群体的本科生的参与;并将纳米级热传输现象整合到本科生/研究生课程中。

This EArly-concept Grant for Exploratory Research (EAGER) project is to develop high performance bulk thermoelectric materials by manipulating their structures at the meso-, micro-, and nano-scale. Achieving a broad range of length scales in the structure of thermoelectric materials is expected to maximize phonon scattering, which will in turn maximize the performance of thermoelectric materials due to the depletion of phononic (or lattice) thermal conduction. Here, the novel idea is to utilize continuum-level fluid mechanics (layering technique) for designing meso/micro-scale structures while creating micro/nano-scale structures with self-assembly and eutectic growth. Through meso-/micro-scale layering and structuring with liquid phase precursors, the size and distribution of nanoparticle inoculants will be manipulated to control the heterogeneous nucleation and solid phase formation at micro-/nano-scales. This new out-of-the-box but high-risk approach integrating fluid mechanics into materials science/engineering will provide new insight and research direction. Thermoelectric energy conversion systems offer an excellent strategy for improving sustainability of our electric power base by scavenging waste heat from various power consuming systems including automobiles and power plants or for providing effective compact cooling for computers and electronic devices with robustness and silence. The research will provide rational and novel methodologies of improving their efficiency by modifying material structures. In addition, research outcomes include crucial knowledge for fully utilizing nanoparticles by solving one of the major hurdles, nanoparticle aggregation. This new approach combining continuum level fluid mechanics and controlling structures down to nanoscale related to material science/engineering may bring subsequent research related to rational design of multi-scale structured materials. The research also include training of Ph.D students with experience in interdisciplinary collaborative research; broadening participation of undergraduate students belonging to underrepresented groups through the NSF-funded Louis Stokes Alliance for Minority Participation at Texas A&M University and the Center for Enhancement of Engineering Diversity at Virgina Tech; and integrating nanoscale thermal transport phenomena into undergraduate/graduate courses.