Enhanced thermoelectric properties of bismuth sulfide polycrystals prepared by mechanical alloying and spark plasma sintering
Enhanced thermoelectric properties of bismuth sulfide polycrystals prepared by mechanical alloying and spark plasma sintering
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DOI：
10.1016/j.jssc.2008.08.022
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发表时间：
2008-12
影响因子：
3.3
通讯作者：
Li-dong Zhao;Boping Zhang;Weishu Liu;Hailong Zhang;Jingfeng Li
中科院分区：
文献类型：
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作者：
Li-dong Zhao;Boping Zhang;Weishu Liu;Hailong Zhang;Jingfeng Li
采用机械合金化法合成了硫化铋粉末，并采用放电等离子烧结（SPS）技术对其进行了烧结。为了改善铋硫化物的电输运性能，通过改变硫的化学组成，产生硫空位，优化载流子浓度，并采用两步SPS热锻工艺，通过增加晶粒取向度，提高载流子迁移率。通过优化硫含量，硫化铋的电阻率从10−2Ωm降低到10− 4 Ωm，并通过热锻进一步降低，从而使功率因数从91 μ W/mK2显著提高到254μW/mK2。热锻Bi_2S_（2.90）样品在523 K时具有最高的ZT=0.11，高于文献报道值。本工作揭示了硫化铋化合物作为一种有希望的热电材料的候选者可以通过一个简单的过程合成。
Bismuth sulfide powders were synthesized by mechanical alloying (MA) and then consolidated by spark plasma sintering (SPS) technique. In order to improve the electrical transport properties of bismuth sulfides, the carrier concentration was optimized by modifying chemical composition of sulfur through producing sulfur vacancies, and the carrier mobility was enhanced by a two-step SPS as a hot-forging process through increasing grain orientation. The electrical resistivity of bismuth sulfides was reduced to 10−4from 10−2Ωm by optimizing sulfur content, and further lowered by hot-forging, whereby the power factor was significantly increased from 91 to 254μW/mK2. The hot-forged Bi2S2.90sample showed the highest ZT=0.11 (at 523K), which is higher than the reported value. The present work revealed that bismuth sulfide compounds as a promising candidate of thermoelectric materials can be synthesized by a simple process.