摘要
Despite an effective p-type dopant for PbTe, the low solubility of Na limits the fully optimization of thermoelectric properties of Na-doped PbTe. In this work, Na-doped PbTe was synthesized under high pressure. The formation of the desired rocksalt phase with substantially increased Na content leads to a high carrier concentration of 3.2×10^20 cm^-3 for Na0.03Pb0.97Te. Moreover, dense in-grain dislocations are identified from the microstructure analysis. Benefited from the improved power factor and greatly suppressed lattice thermal conductivity, the maximal ZT of 1.7 is achieved in the optimal Na0.03Pb0.97Te. Current work thus designates the advantage of high pressure in synthesizing PbTe-based thermoelectric materials.
尽管钠可以对碲化铅进行有效的p型掺杂,但其较低的固溶度限制了对掺杂样品热电性能的全面优化.本工作采用高压合成方法合成钠掺杂的碲化铅样品.结构及成分分析表明样品具有典型的岩盐矿结构,且钠的含量显著提高.相应的,Na_(0.03)Pb_(0.97)Te样品的载流子浓度也提高至3.2×10^(20)cm^(-3).此外,显微结构分析确认在高压合成样品的晶粒中形成了高密度的位错.受益于增强的功率因数和大大抑制晶格热导率,Na_(0.03)Pb_(0.97)Te样品的热电优值达到1.7.该工作展示了压力在合成碲化铅基热电材料中的优势.
基金
supported by the National Natural Science Foundation of China (51525205, 51421091, and 51722209)
the Key Basic Research Project of Hebei (14961013D)
