Investigation of the Thermoelectric Performance of PbTe-Ag2Se Derived Pseudo-solid Solutions, Nanostructures and Nano-composites

PbTe-Ag2Se 拟固溶体、纳米结构和纳米复合材料的热电性能研究

• 批准号: 0905322
• 负责人: Fivos Drymiotis
• 金额: $ 30.5万
• 依托单位: Clemson University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-01 至 2011-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0905322&HistoricalAwards=false
• 关键词: Investigation; Thermoelectric; Performance; PbTe; Ag2Se

TECHNICAL SUMMARY:This project investigates structure formation and electrical and thermal transport properties of PbTe-Ag2-äSe alloys. Solid-solutions of PbTe-Ag2-äSe display extremely interesting structural behavior, low electrical resistivity and very low thermal conductivity. Hence, this system has the potential to give rise to a new state-of ?the-art thermoelectric material for power generation applications. In addition to the favorable transport properties exhibited by the system, the resulting alloys are stable and mechanically robust thus allowing excessive manipulation for optimization of the thermoelectric performance. It has been observed that dense solid-solutions of PbTe-Ag2-äSe (1:1 molar ratio) result in a predominantly single phase alloy which crystallizes in the NaCl structure. Stabilization of a predominantly cubic single phase alloy in the presence of such a high level of structural disorder is remarkable. PbTe appears to dictate structure formation from the melt and not Ag2Se - which stabilizes in an orthorhombic structure at low temperatures and cubic at high temperatures. The PbTe-Ag2-äSe alloys are degenerate semiconductors whose electrical transport correlates with Ag concentration. Preliminary measurements on several samples with ä = 0.1 showed p-type behavior and a high-temperature (~ 400 oC) total thermal-conductivity value êT 0.6 W/m-K. This work will investigate the structure formation of these alloys using x-ray diffraction and microscopy, and study the effects of structure manipulation, i.e. further alloying, nano-structuring and nano-composites, on the thermoelectric properties. This research will provide excellent training for graduate and undergraduate students in material synthesis and characterization. NON-TECHNICAL SUMMARY:This proposal will utilize solid-solutions, nano-structuring and band-gap engineering in order to obtain a high efficiency thermoelectric alloy for power generation applications. Development of thermoelectric materials for power generation is an essential component in our scientific effort to achieve energy independence and security. Thermoelectric materials convert wasted heat to electricity, which implies that any heat source, either man-made (automotives) or natural (hot springs) can be utilized for production of electrical energy. The presence of a temperature gradient across the thermoelectric will give rise to a voltage. Thermoelectric materials also offer the mechanical advantage of absence of moving parts, which eliminates the need for lubrication and frequent maintenance. This work will research the structure formation and high temperature thermoelectric performance of PbTe-Ag2-äSe alloys. These alloys have been shown to have very low thermal conductivity and good electrical conductivity. Both are needed in order to obtain an efficient thermoelectric material. Additionally, the high temperature thermoelectric performance will be optimized through the chemical and mechanical processing of these alloys. This research will provide excellent training for graduate and undergraduate students in material synthesis and characterization. One graduate student and two undergraduate students will be working on this project and will be involved in all aspects of this investigation. The PI actively encourages the participation of women and minorities in his research.

技术概要：本项目研究PbTe-Ag 2-äSe合金的结构形成和电、热传输特性。 PbTe-Ag 2-äSe的固溶体显示出非常有趣的结构行为、低电阻率和非常低的热导率。 因此，这个系统有可能引起一个新的国家？用于发电应用的现有技术热电材料。 除了该系统所表现出的有利的传输特性之外，所得合金是稳定的并且机械上坚固的，因此允许过度操纵以优化热电性能。已经观察到，PbTe-Ag 2-Se（1：1摩尔比）的致密固溶体导致以NaCl结构结晶的主要单相合金。 在存在如此高水平的结构无序的情况下，主要是立方单相合金的稳定是显著的。 碲化铅似乎支配结构形成的熔体，而不是Ag 2Se-它稳定在正交结构在低温和立方在高温下。PbTe-Ag 2-äSe合金是简并半导体，其电输运与Ag浓度相关。 对几个ε = 0.1的样品进行的初步测量显示出p型行为和高温（~ 400 oC）总热导率值为<$T 0.6 W/m-K。 这项工作将使用X射线衍射和显微镜研究这些合金的结构形成，并研究结构操纵，即进一步合金化，纳米结构化和纳米复合材料对热电性能的影响。 这项研究将为研究生和本科生在材料合成和表征方面提供良好的培训。非技术摘要：该提案将利用固溶体、纳米结构和带隙工程，以获得用于发电应用的高效热电合金。开发用于发电的热电材料是我们实现能源独立和安全的科学努力的重要组成部分。 热电材料将废热转化为电能，这意味着任何热源，无论是人造（汽车）还是天然（温泉），都可以用于生产电能。热电偶两端温度梯度的存在将产生电压。热电材料还提供了没有运动部件的机械优势，这消除了润滑和频繁维护的需要。 本文将研究PbTe-Ag_2-Se合金的结构形成和高温热电性能。 这些合金已被证明具有非常低的导热性和良好的导电性。 两者都是需要的，以获得有效的热电材料。此外，高温热电性能将通过这些合金的化学和机械处理来优化。 这项研究将为研究生和本科生在材料合成和表征方面提供良好的培训。 一名研究生和两名本科生将参与这个项目，并将参与调查的各个方面。 PI积极鼓励妇女和少数民族参与其研究。