Bi2Te3/导电聚合物/石墨烯量子阱结构复合热电材料组装及电声输运特性研究

Thermoelectric power generator based on thermoelectric materials is an important renewable energy. This project focuses on the design and fabrication of Bi2Te3/conductive polymer/graphene composite thermoelectric materials by electrochemical synthetical technology. The quatum well composed of nano-layer structure can decrease the thermal conductivity of the composite materials through phonon boundary scattering effectively, while the electrical conductivity of the materials remains high. The graphene modified by conductive polymer or doped Bi2Te3 compounds possesses an energy filtration effect and the change of its forbidden band structure can improve the ZT value. At the same time, the graphene in the composite materials can be connected together by the conductive polymer, which can restrain the decrease of the electric transmission at the connecting points. So the high Seebeck coefficient, electrical conductivity and low thermal conductivity are benefit to increase the ZT value of Bi2Te3/conductive polymer/ graphene composite thermoelectric materials. This project will research the micro-structure of the nano materials and the relationship between the micro-structure and the thermoelectric performance, and propose a theoretical model. Which is important to the design and fabrication of the materials with quatun well structure.

基于热电材料制备的温差电池可将大量低等级热量转变为电能，因此开发高性能热电材料具有重要意义。本研究采用电化学合成技术，设计并构制层状纳米结构Bi2Te3/导电聚合物/石墨烯复合热电材料。这种层状纳米结构形成的量子阱，通过电子局域效应保证材料良好电导率σ的同时，借助于声子边界散射大幅度降低材料的热导率κ。石墨烯经导电聚合物和Bi2Te3掺杂化合物修饰后不仅产生能量过滤效应，其禁带结构的变化使塞贝克系数α提高。同时，导电聚合物能将石墨烯有效连接起来，抑制接触点处电子输运能力降低，充分发挥量子阱结构石墨烯材料的电子输运优势。高α和σ以及低κ有利于量子阱结构Bi2Te3/导电聚合物/石墨烯复合热电材料获得高的ZT值。本项目从研究石墨烯薄膜微结构对电声输运的影响入手，将石墨烯纳米材料的微结构与宏观热电性能相关联，并建立相应的理论模型，指导量子阱结构材料的设计和制备技术优化，具有重要理论意义。

基于热电材料制备的温差电池可将大量低等级热量转变为电能，因此开发高性能热电材料具有重要意义。本研究制备了层状纳米结构导电聚合物/石墨烯和Bi2Te3/导电聚合物/石墨烯复合热电材料。研究结果表明，这种层状纳米结构复合材料具有高的电导率σ和塞贝克系数α，以及低的热导率κ。导电聚合物能将石墨烯有效连接起来，抑制接触点处电子输运能力降低，充分发挥量子阱结构石墨烯材料的电子输运优势,使导电聚合物/石墨烯和Bi2Te3/导电聚合物/石墨烯复合热电材料分别具有较高热电性能。本项目从研究石墨烯纳米材料的微观结构入手,以提高材料宏观热电性能，对热电材料的设计和制备技术优化具有指导意义。