CAREER: Synthesis of Bulk Nanostructured Materials from Semiconductor Quantum Dots

这项教师早期职业发展（CAREER）计划拨款为研究新的制造方法提供资金，用于制造具有纳米长度尺度精确控制结构的大规模材料。虽然纳米结构材料已经从理论和热传输的角度进行了深入的研究，但其加工科学的局限性阻碍了其商业用途。本项目旨在克服这些限制。先进的气相技术将用于合成具有精确控制性能的纳米粉末。将产生具有任意尺寸、尺寸分布、组成和表面化学的超细颗粒，然后烧结以产生具有可调结构细节的块状样品。对纳米粒子性质的精确控制将转化为在纳米结构设计中具有前所未有的自由度的块体纳米结构样品的实现，具有任意设计的纳米结构的块体样品的表征将推进对此类系统中的热和电荷载流子传输的科学理解。将实现对传输性能的晶粒尺寸分布，孔隙度和晶界的局部结构的作用的精确描述。这些知识将可转移到其他物质系统，对科学界很有价值。此外，该项目特别关注地球上丰富的材料以及可扩展到高生产率的合成和加工技术，从而代表了大规模利用具有良好热电转换效率的材料的一个步骤，反之亦然，能源转换效率。这对于废热回收、固态冷却等应用至关重要，通常也是实现更有效利用能源的关键。最后，来自当地高中的学生，来自代表性不足的少数民族的大学生和正在继续接受教育的美国军队退伍军人将直接参与这些研究活动，以加强他们在材料，制造和能源等战略重要领域的教育。

This Faculty Early Career Development (CAREER) Program grant provides funding to investigate new manufacturing approaches for the fabrication of bulk-scale materials with precisely controlled structure at the nanometer length scale. While nanostructured materials have been intensively investigated from the theoretical and thermal transport points of view, limitations in their processing science have impeded their commercial use. This project aims at overcoming these limitations. Advanced gas-phase techniques will be used to synthesize nanopowders with precisely controlled properties. Ultrafine particles with arbitrary size, size distribution, composition and surface chemistry will be produced and then sintered to yield bulk samples with tunable structural details. The precise control of the nanoparticle properties will translate into the realization of bulk nanostructured samples with an unprecedented degree of freedom in the design of their nanostructure.The characterization of bulk samples with arbitrarily designed nanostructure will advance the scientific understanding of transport of heat and charge carriers in such systems. A precise description of the role of grain size distribution, porosity and local structure of grain boundaries on transport properties will be achieved. This knowledge will be transferrable to other material systems and valuable to the scientific community. Moreover, the project specifically focuses on earth-abundant materials and on synthesis and processing techniques that are scalable to high production rates, thus representing a step towards the large-scale utilization of materials with good thermal-to-electrical, and vice versa, energy conversion efficiency. This is critical for applications such as waste heat recovery, solid state cooling, and in general, for achieving a more effective utilization of our energy resources. Finally, students from local high schools, college students from underrepresented minorities and veterans from the US military who are continuing their educations will be directly involved in these research activities to enhance their education in the strategically important areas of materials, manufacturing and energy.