摘 要

碲化铋半导体材料是常温下最常见的热电材料之一，室温下具有良好的热电特性，能够实现热能和电能的相互转化，应用前景十分广阔。碲化铋热电材料的低转化效率是影响其应用的瓶颈之一，目前世界范围内的研究热点主要集中在如何提高热电材料的能量转换效率上。

碲化铋作为最常见、应用最广的热电材料，对其原料配比、制备工艺有极大的改进和研究空间。本实验将对某一特定原料配比进行制备和评价。碲化铋的制备一般采用区熔法、机械合金化、溶剂热合成法、热压法、放电等离子烧结等工艺。本实验通过SPS以及气氛炉工艺制备，以及设置不同烧结温度等工艺参数，对热电系数进一步改善。

本研究采用放电等离子烧结与气氛炉烧结法制备碲化铋的半导体晶粒，通过X射线衍射分析技术，表征碲化铋样品的晶体结构和物相组成。另外分别对材料的塞贝克系数、电导率以及热扩散系数等热电系数进行测量。综合实验数据，比较制得碲化铋材料不同烧结温度下的结构与性能的优劣，从而评价方案的优缺点，考量各种方案的商业价值。

关键词：碲化铋；热电材料；制备工艺；热电系数

Abstract

Bismuth telluride semiconductor material is one of the most common thermoelectric materials at room temperature, and has good thermoelectric properties at room temperature, which can realize the conversion between thermal energy and electric energy, and has broad application prospects. The low conversion efficiency of bismuth telluride thermoelectric materials is one of the bottlenecks that affect its application. At present, the research focuses on how to improve the energy conversion efficiency of thermoelectric materials.

Bismuth telluride as the most common and widely used thermoelectric materials, its raw materials ratio, the preparation process has a great improvement and research space.This experiment will make the preparation and evaluation of a certain proportion of raw materials. Bismuth telluride was prepared by zone melting method, mechanical alloy, solvothermal, hot pressing, spark plasma sintering(SPS) process. In this experiment, the thermoelectric coefficient is improved by SPS and the process of atmosphere furnace, as well as the setting of different sintering temperature and other parameters.

In this study, the crystal structure and phase composition were characterized by X - ray diffraction analysis, which was used for the preparation of bismuth telluride semiconductor crystal grains by spark plasma sintering and atmosphere furnace. In addition to the material were measured respectively the Seebeck coefficient and electrical conductivity and thermal diffusion coefficient of thermoelectric coefficient. Based on comprehensive experimental data, the advantages and disadvantages of the structure and properties of bismuth telluride material at different sintering temperatures were compared, and the advantages and disadvantages of the scheme were compared, and the commercial value of various schemes was considered.

Keywords: Bismuth telluride；Thermoelectric materials；Processing technique；Thermoelectric coefficient

目录

摘 要 I

Abstract II

第1章 绪论 - 1 -

1.1 热电材料原理与应用 - 1 -

1.1.1 热电效应及热电材料 - 1 -

1.1.2 热电优值系数定义与指标 - 2 -

1.1.3 热电材料的应用现状 - 3 -

1.2 碲化铋材料性质与应用 - 7 -

1.2.1 碲化铋材料 - 7 -

1.2.2 碲化铋材料的应用 - 7 -

1.2.3 热电优值的选择和提高途径 - 8 -

1.3 研究的目的及意义 - 9 -

第 2 章 碲化铋晶体的制备 - 10 -

2.1 实验质料与制备 - 10 -

2.2 实验流程图 - 14 -

2.3 工艺参数确定 - 16 -

第3章 碲化铋表征 - 18 -

3.1 XRD分析 - 18 -

3.1.1 XRD分析原理 - 18 -

3.1.2 X射线衍射分析仪 - 18 -

3.1.3 X射线衍射谱分析 - 19 -

3.2热电性能测试 - 22 -

3.2.1 热电性能测试原理 - 22 -

3.2.2 热电性能测试仪器 - 24 -

3.2.3 热电性能测试结果 - 26 -

3.2.4 结果分析 - 27 -

第 4 章 结论 - 30 -

参考文献 - 31 -

致谢 - 33 -

第1章 绪论

自1823年Thomas Seebeck发现了塞贝克效应(即热电效应)，人们开始了解热电材料，经过一百多年的努力，人们对热电材料的制备和应用已经取得了长足的进展。至20世纪60年代，由于人们在热能电能相互转化特别是制冷方面的迫切需求，人们研究了许多有生产价值的热电材料，其中有许多热电材料取得了广泛的应用。因此，在能源危机和环境污染日益严重的今天，新型热电材料的研究具有很重要的现实意义。

半导体材料是室温下最常见的热电材料之一。因其良好的热电特性,能够实现电能和热能的相互转化，应用前景十分广泛。热电材料的转换效率不够高是影响其应用效益的瓶颈之一，目前世界范围内的研究热点主要集中在如何提高热电材料的能量转换效率和热电优值系数上。

1.1 热电材料原理与应用