Enhanced near-room-temperature thermoelectric performance in GeTe

• Published in: Rare metals Vol. 41; no. 9; pp. 3027 - 3034
• Main Authors: Tan, Xian Yi, Dong, Jin-Feng, Jia, Ning, Zhang, Hong-Xia, Ji, Rong, Suwardi, Ady, Li, Zhi-Liang, Zhu, Qiang, Xu, Jian-Wei, Yan, Qing-Yu
• Format: Journal Article
• Language: English
• Published: Beijing Nonferrous Metals Society of China 01.09.2022; Springer Nature B.V
• Subjects: Alloying; Biomaterials; Bismuth; Carrier density; Chemistry and Materials Science; Doping; Energy; Figure of merit; Materials Engineering; Materials Science; Metallic Materials; Nanoscale Science and Technology; Original Article; Physical Chemistry; Point defects; Power factor; Room temperature; Seebeck effect; Temperature; Thermal conductivity; Thermoelectric materials; Thermoelectricity; Transport properties; Thermal conductivity; Thermoelectric; Room-temperature; GeTe
• ISSN: 1001-0521; 1867-7185
• DOI: 10.1007/s12598-022-02036-8

GeTe is an excellent mid-temperature thermoelectric material with high dimensionless figure of merit ( ZT ) values at temperatures over 600 K. Its near-room-temperature performance is less studied due to the intrinsic high carrier concentration. Here, we successfully enhance the Seebeck coefficient of GeTe from ~ 30 to 220 μV·K −1 at 300 K, which is achieved by AgInSe 2 alloying and Bi doping. It is demonstrated that Bi doping helps to optimize the Seebeck coefficient without deteriorating the intrinsic electrical transport properties of the matrix. A high room-temperature power factor (PF) of ~ 11 μW·cm −1 ·K −2 is achieved for a wide range of Bi-doped samples. The simultaneously introduced abundant point defects cause mass and strain fluctuations, which decrease the lattice thermal conductivity ( κ L ) to a low value of 0.6 W·m −1 ·K −1 at 300 K. Due to the synergetic effects of Bi doping in AgInSe 2 -alloyed GeTe, a high room-temperature ZT value of 0.46 is obtained together with a high ZT value of 1.1 at 523 K. Graphical abstract