Enhanced Thermoelectric Properties of Cu3SbSe4 Compounds by Isovalent Bismuth Doping

• Published in: Journal of materials science. Materials in electronics 2021-07, Vol.32 (14), p.18849-18861
• Main Authors: Zhao, Lijun, Wang, Mingyuan, Yang, Jian, Hu, Jiabin, Zhu, Yuan, Liu, Guiwu, Hussain, Shahid, Shao, Haicheng, Lei, Shuangying, Wan, Neng, Shi, Zhongqi, Qiao, Guanjun
• Format: Article
• Language: English
• Subjects: Amorphous materials; Bismuth; Carrier density; Characterization and Evaluation of Materials; Chemistry and Materials Science; Copper selenides; Crystal defects; Doping; Grain boundaries; Heat conductivity; Heat transfer; Heavy elements; Hot pressing; Materials Science; Optical and Electronic Materials; Point defects; Power factor; Seebeck effect; Thermal conductivity; Thermoelectric materials; Thermoelectricity; X ray photoelectron spectroscopy
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-021-06403-6

Cu 3 SbSe 4 , featuring its earth-abundant, cheap, nontoxic and environmentally friendly constituent elements, can be considered as a promising intermediate temperature thermoelectric (TE) material. Herein, a series of p-type Bi-doped Cu 3 Sb 1− x Bi x Se 4 ( x  = 0–0.04) samples were fabricated through melting and hot pressing process, and the effects of isovalent Bi-doping on their TE properties were comparatively investigated by experimental and computational methods. TEM analysis indicates that Bi-doped samples consist of Cu 3 SbSe 4 and Cu 2− x Se impurity phases, which is in good agreement with the results of XRD, SEM and XPS. For Bi-doped samples, the reduced electrical resistivity ( ρ ) caused by the optimized carrier concentrations and enhanced Seebeck coefficient derived from the densities of states near the Fermi level give rise to a high power factor of ~ 1000 µWm −1  K −2 at 673 K for the Cu 3 Sb 0.985 Bi 0.015 Se 4 sample. Additionally, the multiscale defects of Cu 3 SbSe 4 -based materials involving point defects, nanoprecipitates, amorphous phases and grain boundaries can strongly scatter phonons to depress lattice thermal conductivity ( κ lat ), resulting in a low κ lat of ~ 0.53 Wm −1  K −1 and thermal conductivity ( κ tot ) of ~ 0.62 Wm −1  K −1 at 673 K for the Cu 3 Sb 0.98 Bi 0.02 Se 4 sample. As a consequence, a maximum ZT value ~ 0.95 at 673 K is obtained for the Cu 3 Sb 0.985 Bi 0.015 Se 4 sample, which is ~ 1.9 times higher than that of pristine Cu 3 SbSe 4 . This work shows that isovalent heavy element doping is an effective strategy to optimize thermoelectric properties of copper-based chalcogenides.