Improving Thermoelectric Performance of α‐MgAgSb by Theoretical Band Engineering Design. Issue 18 (23rd May 2017)

• Record Type: Journal Article
• Authors: Tan, Xiaojian; Wang, Ling; Shao, Hezhu; Yue, Song; Xu, Jingtao; Liu, Guoqiang; Jiang, Haochuan; Jiang, Jun
• Is Part Of: Advanced energy materials. Volume 7:Issue 18(2017)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-05-23
• Subjects: band engineering -- MgAgSb -- thermoelectric; Energy harvesting -- Materials -- Periodicals; Energy conversion -- Materials -- Periodicals; Energy storage -- Materials -- Periodicals; Photovoltaics -- Periodicals; Fuel cells -- Periodicals; Thermoelectric materials -- Periodicals; 621.31
• DOI: 10.1002/aenm.201700076
• Languages: English
• ISSNs: 1614-6832

Abstract

Abstract : α‐MgAgSb is recently discovered to be a new class of thermoelectric material near room temperature. A competitive ZT of 1.4 at 525 K is achieved in Ni‐doped α‐MgAgSb, and the measured efficiency of energy conversion reaches a record value of 8.5%, which is even higher than that of the commercially applied material bismuth telluride. On the other hand, the band structure of α‐MgAgSb is believed to be unprofitable to the power factor, owing to the less degenerate valence valleys. Here, this paper reports a systematic theoretical study on the thermoelectric properties by using the electron/phonon structure and transport calculations. Based on the careful analysis of Fermi surface, a principled scheme is presented to design band engineering in α‐MgAgSb. Following the given rules, several effective dopants are predicted. As two examples, Zn‐ and Pd‐doped α‐MgAgSb are numerically confirmed to exhibit an extraordinary ZT value of 2.0 at 575 K and a high conversion efficiency of 12.6%, owing to the effects of band convergence. This work develops an applicable scheme for the purposive design of band engineering, and the idea can be simply applied to more thermoelectric materials. Abstract : A principled scheme is proposed to design the band engineering based on careful analysis of Fermi level. Several effective dopants are predicted and numerically examined to enhance the thermoelectric performance of α‐MgAgSb by band convergence. This work develops an applicable scheme for the purposive band engineering design, and the idea can be simply applied to more thermoelectric materials.