提高p型PbS的热电性能,使用CdS和ZnS的内毒性纳米结构和价值带偏移工程来提高PbS的热电性能
Li-Dong Zhao1, Jiaqing He, Shiqiang Hao
1Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA.
Journal of the American Chemical Society
|September 21, 2012
概括
我们使用硫化 (CdS) 纳米结构增强了硫化 (PbS) 的热电特性. 这种方法在保持电导率的同时降低了导热率,达到约1.3.3的功率 (ZT) 值.
科学领域:
- 材料科学 材料科学 材料科学
- 固态物理 固态物理
- 纳米技术 纳米技术
背景情况:
- 热电材料将热转化为电力,这对于废热回收至关重要.
- 硫化 (PbS) 是一个有前途的热电材料,但其效率受到导热率的限制.
- 纳米结构和组合二级相可以优化热电性能.
研究的目的:
- 研究硫化物 (CdS) 和硫化物 (ZnS) 作为二级相对p型硫化物 (PbS) 的热电特性的影响.
- 了解增强热电性能背后的机制,重点关注声子散射和电荷传输.
- 探索PbS和嵌入金属硫化物之间的带对齐的作用.
主要方法:
- 纳化p型PbS与内毒性纳米结构CdS的合成.
- 测量热电性质,包括功率图 (ZT),导热率和功率因子.
- 传输电子显微镜 (TEM) 用于描述纳米结构.
- 密度函数理论 (DFT) 计算以确定价值和导电带能量水平和带偏移.
主要成果:
- 在Na-doped PbS中,在923K时达到约1.3的热电功率 (ZT),其中3.0%的CdS纳米结构为3.0.
- 证明CdS通过广泛的语子散射有效地降低了晶格导热率.
- 通过连贯接口确定了有利的电荷传输,并将PbS和CdS之间的价值带偏移 (~0.13 eV) 降到最低,从而保持载体移动性和功率因子.
结论:
- 在p型PbS中嵌入内毒性纳米结构的CdS显著提高了热电性能.
- 结合声子阻断 (降低热导率) 和电子传导 (保持电导率) 的策略是有效的.
- 这种方法通过仔细选择和整合二级纳米相沉物来改善热电材料的途径.
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