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热电材料是一类能够实现热与电相互转换的功能材料,在制冷和发电领域极具应用潜力.本文采用金属Sb元素非等电子替换Cu3Ga5Te9化学式中的Cu和Te,观察到材料Seebeck系数和电导率提升的现象.这些电学性能的改善与载流子浓度和有效质量的增大及迁移率基本维持不变有关.载流子浓度的提高是由于Sb原子占位在Te晶格位置后费米能级进入到价带所产生的空穴掺杂效应所致,同时也与Cu含量减少后铜空位(V-1Cu)浓度增大相关联.另外,非等电子替换后,阴离子(Te2-)移位导致了晶格结构缺陷参数u和η的改变,其改变量fiu和fiη与材料晶格热导率(κL)的变化密切相关.在766 K时,适量的Sb替换量使材料的最大热电优值(ZT)达到0.6,比Cu3Ga5Te9提高了近25%.因此,通过选择替换元素、被替换元素及替换量有效地调控了材料的电学及热学性能,在黄铜矿结构半导体中实现了非等电子元素替换改善热电性能的思想.
Thermoelectric materials are a kind of functional materials that can convert heat and electricity into each other and have great potential applications in refrigeration and power generation.In this paper, Cu and Te in Cu3Ga5Te9 chemical formula are replaced by non-equivalent electrons of metal Sb, the Seebeck coefficient and conductance Rate of improvement of these electrical performance improvement and carrier concentration and effective mass increase and mobility remained unchanged.Characteristic of the carrier concentration is due to the atomic Sb occupied in the Te lattice position after the Fermi (V-1Cu) concentration increases with the decrease of Cu content.In addition, after the non-equivalent electron exchange, the anion (Te2-) The displacement leads to the change of the lattice structure defect parameters u and η, and the change amounts fiu and fiη are closely related to the change of lattice thermal conductivity (κL). At 766 K, the amount of Sb substitution makes the material maximum The thermoelectric figure of merit (ZT) reaches 0.6, which is nearly 25% higher than that of Cu3Ga5Te9. Therefore, the electrical and thermal properties of the material are effectively controlled by the choice of replacement elements, replaced elements and substitutions, Non-equivalent electronic element replacement Good idea thermoelectric properties.