晶界热电材料:热电参数调控策略及研究进展  

Thermoelectric materials with grain boundary:Strategies to parameters

作　　者：李雨欣 何文科 Yuxin Li;Wenke He(Institute of Fundamental and Frontier Sciences,University of Electronic Science and Technology of China,Chengdu 610500,China)

机构地区：[1]电子科技大学基础与前沿研究院,成都610500

出　　处：《科学通报》2025年第6期624-635,共12页Chinese Science Bulletin

基　　金：国家自然科学基金(22205032);中国科协“青年托举人才工程”(2022QNRC001);电子科技大学“百人计划”资助。

摘　　要：多晶热电材料中,晶界作为各类缺陷形成以及调控的重要场所,在热电输运中扮演着重要角色.本文系统阐述了晶界处不同缺陷对电子和声子的影响及其作用机制,并系统地总结了基于晶界调控实现热电参数提升及协同优化的有效策略.首先,通过分析晶界对载流子输运的积极作用,分别阐释了晶界处动态掺杂调控载流子浓度,晶界相结构(导电通道、高介电常数相、晶界角度、能带对齐)优化载流子迁移率,以及界面能量过滤效应增强Seebeck系数的有效机制.然后,通过分析晶界对声子输运的阻碍作用,分别归纳了晶界处本征相(晶粒细化)和非本征相(纳米第二相)结构对声子散射的增强机制.此外,通过分析晶界处载流子和声子的解耦机制,提出实现热电输运性能协同优化的有效方法(如优化晶粒尺寸、引入共格或半共格第二相等).最后,指出通过深入理解晶界微观机制、高效设计晶界结构、解耦调控电声输运,建立微观结构-晶界调控-热电性能之间的构效关系,为未来高效晶界热电材料的研发提供理论和实验基础.Thermoelectric conversion technology is a novel clean energy technology that directly converts heat into electricity utilizing the thermoelectric effect of materials.The optimization of thermoelectric performance in materials has garnered widespread attention and research,where the carrier and phonon transports directly determine the final figure of merit(ZT).Grain boundaries,the most common microstructures or defects in polycrystalline materials,significantly impact the transport behaviors of carriers(electrons or holes)and phonons.On the one hand,grain boundaries are the locus of various defects,which adversely affect carrier transport and thereby inhibit electrical performance.The most intuitive effect is carrier scattering at grain boundaries,which encompasses grain boundary scattering and barrier scattering.Furthermore,the trap effect and depletion region effect at grain boundaries also impede carrier transport.On the other hand,grain boundaries can also act as intense scattering centers for phonons,hindering heat transport.Phonons can be scattered at grain boundaries,altering their direction and energy of propagation,leading to changes in phonon transport paths.Consequently,these altered phonon transport behaviors enhance the thermal resistance and diminish the thermal conductivity of the material.Additionally,the irregular arrangement of atoms at grain boundaries may give rise to localized phonon states,creating an additional barrier to phonon transport.Therefore,understanding and controlling electron-phonon transport behaviors at grain boundaries is crucial for enhancing the thermoelectric performance of polycrystalline materials.This review paper focuses on the impact of microstructures on the behaviors of carriers and phonons at grain boundaries,and systematically summarizes effective strategies for regulating thermoelectric transport parameters based on grain boundary engineering.Firstly,we delve into effective mechanisms and propose strategies to optimize electrical transport by analyzing carrier beha

关 键 词：热电材料 晶界工程 载流子 声子 迁移率 

分 类 号：TB34[一般工业技术—材料科学与工程]