纳米复合热电材料研究进展

Recent Progress of Thermoelectric Nano-composites

低维化和纳米化实现电、声输运特性的协同调控从而优化热电性能是当前热电材料领域的一个重要研究方向.通过外混、原位复合等方式引入的纳米颗粒能散射具有中长波波长的声子从而降低材料的晶格热导率,同时纳米化有助于载流子在费米能级附近态密度的提高,纳米颗粒构成的界面所产生的界面势垒能有效过滤低能量载流子,从而增大赛贝克系数.纳米颗粒的含量、分散状态以及颗粒本征性质是设计高性能纳米复合热电材料的关键.对于不同材料体系,外部混合、原位氧化、分相析出等制备方法为实现微结构控制提供了可能.本文以几个典型材料体系为例介绍微结构调控提高材料热电性能的研究进展,并讨论微结构调控对电、声输运的影响机制.

Microstructure engineering is an effective avenue for tuning the thermal and electrical transports to optimize thermoelectric（TE） properties.Thermoelectric composites with nano-particle dispersion have been successfully developed by using extrinsic or in-situ formation methods.The lattice thermal conductivity can be depressed by the scattering effects of nano particles to the medium-long-wavelength phonons.The enhanced electron density of states at the Fermi level and the carrier filtering effects caused by the nano-sized grain boundary are also positive for enhancing Seebeck coefficients.The mixing,in-situ oxidation and phase-separation precipitation process supply possibility to realize the nano-particle dispersed structure for different material systems.This paper reviews the recent progress of the research on nano-structured and nano-composite thermoelectric materials.The effects of the nano-dispersion on the electrical and thermal transports will be also discussed.