CAREER: Printing and Interface Engineering of Colloidal Nanocrystals for Flexible Thermoelectrics and Electronics

这个教师早期职业发展（CAREER）奖旨在开发新的方法来使用纳米晶体形成热电材料和设备。柔性热电和电子薄膜具有影响能量收集、冷却和柔性电子产品中广泛应用的潜力。传统的热电和电子器件是刚性的，并且使用复杂且相对昂贵的工艺制造。增材制造或基于打印的方法提供了低成本和高度可扩展的手段，将具有独特特性的胶体纳米晶体组装成柔性热电和电子器件。热电材料的纳米晶体由于其小尺寸，可以形成为可以印刷到柔性基板上的油墨，并且可以形成有用的接近最终形式的结构。纳米晶体及其相互界面的热和电性质需要在工作装置中理解和控制。在加工条件下，界面化学和纳米陶瓷基薄膜的热电行为的响应对于获得最高性能的热电材料至关重要。这些基于纳米陶瓷的工艺和材料可以开辟新的应用领域，影响美国制造业，并开辟热电以外的新应用领域。综合研究和教育计划为广泛的受众提供教育机会，包括开发热电开发和机构和推广计划的教育工具包，以提高K-12学生，教师和代表性不足的群体成员对STEM职业的兴趣，通过参与NSF REU/RET，LSAMP，电子女孩和电子营地，支持制造业和先进材料领域的劳动力发展，以满足可持续能源和电子技术日益增长的需求。这项研究旨在实现块状电荷载流子迁移率，并将热电优值ZT提高两倍以上-最先进的柔性薄膜。该研究将解决在可扩展和低成本制造过程中将纳米晶体转化为有用形式的迫切需求。该项目将完成四个目标，以建立从纳米尺度到宏观尺度处理胶体纳米晶体的新范式：（1）纳米晶体的合成，并控制其尺寸，表面化学和掺杂，（2）打印和烧结柔性薄膜，控制界面化学，（3）建立加工-结构-性能关系，（4）设计和打印概念验证设备。研究成果不仅将大大推进柔性热电和电子材料的制造工艺，还将在增材打印平台内形成和使用功能性纳米晶材料方面产生新的知识。

This Faculty Early Career Development (CAREER) award looks to develop new approaches to the use of nanocrystals in the formation of thermoelectric materials and devices. Flexible thermoelectric and electronic films have the potential to impact a broad range of applications in energy harvesting, cooling and flexible electronics. The conventional thermoelectric and electronic devices are rigid, and fabricated using complex and relative costly processes. Additive manufacturing or printing-based approaches offer low-cost and highly scalable means to assemble colloidal nanocrystals of unique properties into flexible thermoelectric and electronic devices. Nanocrystals of thermoelectric materials, because of their small size, can be formed into inks which can be printed onto flexible substrates and in useful near-final-form structures. The thermal and electrical properties of the nanocrystals and their mutual interfaces need to be understood and controlled in working devices. The interfacial chemistry and the response of the nanocrystal-based film's thermoelectric behavior under processing conditions is critical to achieving the highest performance thermoelectric materials. These nanocrystal-based processes and materials could open new application areas impacting US manufacturing and opening new application area beyond thermoelectrics. The integrated research and education program provides educational opportunities to broad range of audiences, including the development of educational kits in thermoelectrics development and institutional and outreach programs to enhance interest from K-12 students, teachers and members of underrepresented groups in STEM careers through participation in NSF REU/RET, LSAMP, e-Girls, and e-Camp, to support workforce development in the manufacturing and advanced materials areas to address increasing needs in the sustainable energy and electronic technologies.This research aims to achieve bulk-like charge carrier mobility and an over two-fold increase in thermoelectric figure of merit ZT compared with current state-of-the-art flexible films. The research will address a pressing need to convert the nanocrystals into a useful form within a scalable and low-cost manufacturing process. The project will complete four objectives to establish a new paradigm for processing colloidal nanocrystals from nanoscale-to-macroscale: (1) synthesis of nanocrystals, and control their size, surface chemistry and doping, (2) print and sinter flexible films, with controlled interfacial chemistry, (3) establish the processing-structure-property relationship, and (4) design and print proof-of-concept devices. The research outcomes will not only significantly advance the manufacturing processes for flexible thermoelectric and electronic materials, but also generate new knowledge in the formation and use of functional nanocrystalline materials within an additive printing platform.