The focus of this paper is on the Bi2Te3 base material。 The synthesis method of aqueous solution was adopted to synthesize the Bi2Te3nanocrystalline powders。 Because the aqueous solution synthesis method is carried out under the open system, it can simplify the whole reaction process comparatively compared to hydrothermal synthesis of hydrothermal solvent。 The Xrd Fe-sem and other methods were used to analyze the structure of phase composition and microstructure, and the chemical reaction mechanism in the process of hydrothermal synthesis of Bi2Te3 was studied and discussed experimentally。 Finally, the cold pressure technology was used to Bi2Te3nanocrystalline powders and to test their thermoelectric properties。 The main findings of this paper are as follows:

1。 BiCl3and Te powder as the basis of the reaction raw materials, deionized water as a solvent, KBH4 as an alkaline regulator, the effect of different reaction temperature (55,65,75℃) on the preparation of Bi2Te3Nanocrystalline powders was studied by using the method of aqueous solution synthesis, and the chemical reaction mechanism and nucleation growth mechanism of Bi2Te3 hydrothermal synthesis process were KBH, The effects of different reaction temperatures on the phase compositions and microstructure of Bi2Te3 nanocrystals were analyzed and the thermoelectric properties of the samples were tested。 Experimental 

show that when the low synthesis temperature-55℃, the reaction can be completed quickly and the Bi2Te3 nanocrystals of the pure phase are synthesized; however, when the reaction temperature is 65℃, the electrical properties of the nanocrystals are best, and the power factor can reach 23 X 10 at room temperature。

2。 BiCl3and Te powder as the basis of the reaction raw materials, deionized water as a solvent, KBH4 as an alkaline regulator, KBH4 as a reducing agent, the reaction temperature of 65℃, the use of aqueous solution synthesis, the Bi2Te3nanocrystalline powders were prepared by sodium ZE-EDTA disodium EDTA as surfactant, and the effect of ethylenediamine-two amine disodium diacetate on the growth mechanism of Bi2Te3nanocrystalline nuclei was discussed, and the ethyl two amine disodium diacetate (EDTA) was analyzed。 The effects of Bi2Te3 nanocrystals on phase compositions and microstructure were tested and the thermoelectric properties of the samples were measured。 The experimental results show that after adding surfactant, the morphology of Bi2Te3nanocrystalline Flakes is more regular, and the effect of sodium EDTA in the process of synthesis is controlled by two amine。 And when the content of two amine disodium diacetate (EDTA) was increased to 2g, the characteristic peaks of Te disappeared, which showed that the Bi2Te3 nanocrystals of pure phase were synthesized, but their electrical properties decreased lower than that before EDTA。

Keywords: thermoelectric materials; aqueous solution synthesis; Bi2Te3; nanocrystalline

目录

摘要 i

Abstract ii

目录 iv

1热电学基本理论和研究进展 1

1。1热电材料基本理论 2

1。1。1热电材料研究历史 2

1。1。2热电效应及热电参数 3

1。1。3热电材料的应用 6

1。2Bi2Te3热电材料研究背景及现状 7

1。2。1 Bi2Te3的发展历史 7

1。2。2 Bi2Te3纳米化 8

2Bi2Te3纳米晶研究方法 11

2。1材料的制备方法 11

2。2物相和形貌分析