Heavy Doping and Band Engineering by Potassium to Improve the Thermoelectric Figure of Merit in p-Type PbTe, PbSe, and PbTe1-ySey
Heavy Doping and Band Engineering by Potassium to Improve the Thermoelectric Figure of Merit in p-Type PbTe, PbSe, and PbTe1-ySey
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DOI：
10.1021/ja301245b
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发表时间：
2012-06-20
影响因子：
15
通讯作者：
Ren, Zhifeng
中科院分区：
文献类型：
--
作者：
Zhang, Qian;Cao, Feng;Ren, Zhifeng
我们在PbTe1-ySey中详细研究了钾掺杂（y = 0, 0.15, 0.25, 0.75, 0.85, 0.95和1）。结果表明，硒增加了PbTe中K的掺杂浓度，这是由于电负性的平衡，同时由于点缺陷数量的增加，硒降低了PbTe中K的晶格热导率。通过调整组成和载流子浓度来增加费米能级附近的态密度，可以提高PbTe1-ySey两个价带的塞贝克系数。富te的K0.02Pb0.98Te0.75Se0.25 us在773 K和富se的K0.02Pb0.98Te0.15Se0.85在873 K的峰值热电性能值（ZT）分别接近1.6和1.7。富te组分的平均ZT高于富se组分，其中K0.02Pb0.98Te0.75Se0.25的ZT最好。这样的结果是由于在Se的帮助下重K掺杂改善了电子传递。
We present detailed studies of potassium doping in PbTe1-ySey (y = 0, 0.15, 0.25, 0.75, 0.85, 0.95, and 1). It was found that Se increases the doping concentration of K in PbTe as a result of the balance of electronegativity and also lowers the lattice thermal conductivity because of the increased number of point defects. Tuning the composition and carrier concentration to increase the density of states around the Fermi level results in higher Seebeck coefficients for the two valence bands of PbTe1-ySey. Peak thermoelectric figure of merit (ZT) values of similar to 1.6 and similar to 1.7 were obtained for Te-rich K0.02Pb0.98Te0.75Se0.25 us at 773 K and Se-rich K0.02Pb0.98Te0.15Se0.85 at 873 K, respectively. However, the average ZT was higher in Te-rich compositions than in Se-rich compositions, with the best found in K0.02Pb0.98Te0.75Se0.25. Such a result is due to the improved electron transport afforded by heavy K doping with the assistance of Se.