AgBiSe_(2)合金化稳定SnSe立方相结构及其热电性能的研究

Study on the Structure and Thermoelectric Performance of SnSe Cubic Phase Stabilized by AgBiSe_(2) Alloying

SnSe是一种具有简单结构的二元化合物。在约793 K时,SnSe发生相变,随温度的升高,SnSe会从低对称低温相(Pnma)转变为高对称高温相(Cmcm)。除去这两种层状结构,另一种立方相(Fm3m)结构的SnSe也被热力学证明可以稳定存在。近年来,正交相SnSe得到了广泛的发展,亚稳态立方相SnSe作为有潜力热电材料的候选材料之一也受到了广泛的关注。通过真空熔融-退火-球磨-急速热压工艺合金化AgBiSe_(2)来稳定SnSe的立方相结构。通过AgBiSe_(2)的合金化可得到较高的载流子浓度和较强的声子缺陷散射。随着功率因子的增加,热导率的减小,样品的热电性能得到了显著提高。

SnSe is a binary compound with simple structure.At about 793 K,SnSe can undergo a phase transition.With the increase of temperature,SnSe can transform from low symmetric phase(Pnma)at low temperature to high symmetric phase(Cmcm)at high temperature.Apart from these two layered structures,another cubic phase(Fm3m)SnSe has also been thermodynamically proved to exist stably.Recently,orthorhombic SnSe had an extensive development.The metastable cubic phase SnSe has received great attention as one of candidates of promising thermoelectric materials.Herein,the cubic phase of SnSe was stabilized by AgBiSe_(2) alloying with a vacuum melting-annealing-ball milling-rapidly hot-pressing sintering process.The alloying of AgBiSe_(2) resulted in the higher carrier concentration and stronger phonon defect scattering.With the increase of the power factor and the decrease of thermal conductivity,the thermoelectric performance of samples are significantly improved.