Synergistic effect of CuInSe 2 alloying on enhancing the thermoelectric performance of Cu 2 SnSe 3 compounds

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2020-10, Vol.8 (40), p.21181-21188
• Main Authors: Fan, Yijing, Wang, Guoyu, Zhang, Bin, Li, Zhe, Wang, Guiwen, Zhang, Xiao, Huang, Yuling, Chen, Kansong, Gu, Hao-shuang, Lu, Xu, Zhou, Xiaoyuan
• Format: Article
• Language: English
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/D0TA07211G

Cu 2 SnSe 3 based compounds with a diamond-like structure are promising thermoelectric materials. However, the relatively high lattice thermal conductivity limits further improvement in their thermoelectric performance. In this work, two compounds including In 2 Se 3 and CuInSe 2 are employed to alloy with Cu 2 SnSe 3 aiming to decrease lattice thermal conductivity and their corresponding effects are compared. It is found that alloying with CuInSe 2 is more beneficial to reduce lattice thermal conductivity and maintain the power factor, as evidenced by a higher quality factor B . Subsequently, both In and Ga doping is performed to regulate the carrier concentration of (Cu 2 SnSe 3 ) 0.80 (CuInSe 2 ) 0.2 . Finally, (Cu 2 Sn 0.97 Ga 0.03 Se 3 ) 0.80 (CuInSe 2 ) 0.20 displays a decent zT of ∼0.98 at 823 K, a nearly six-fold higher value compared to that of the pristine sample. Additionally, a zT ave of ∼0.35 over 300–823 K is obtained in (Cu 2 Sn 0.97 Ga 0.03 Se 3 ) 0.80 (CuInSe 2 ) 0.20 , which is among the best reported p-type Cu 2 SnSe 3 based compounds. The result proves that alloying with CuInSe 2 combined with carrier concentration optimization is a valid strategy to improve the thermoelectric performance of Cu 2 SnSe 3 based compounds.