The effect of Mg3As2 alloying on the thermoelectric properties of n-type Mg3(Sb, Bi)2. Issue 27 (30th June 2021)

• Record Type: Journal Article
• Authors: Imasato, Kazuki; Anand, Shashwat; Gurunathan, Ramya; Snyder, G. Jeffrey
• Is Part Of: Dalton transactions. Volume 50:Issue 27(2021)
• Page Start: 9376
• Page End: 9382
• Publication Date: 2021-06-30
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/d1dt01600h
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : The effect of Mg3 As2 alloying on thermoelectric properties of Mg3 (Sb, Bi)2 has been investigated. While the crystal structure of pure Mg3 As2 is different from Mg3 (Sb, Bi)2, at least 15% arsenic solubility on anion site is confirmed. Abstract : Mg3 Sb2 –Mg3 Bi2 alloys have been heavily studied as a competitive alternative to the state-of-the-art n-type Bi2 (Te, Se)3 thermoelectric alloys. Using Mg3 As2 alloying, we examine another dimension of exploration in Mg3 Sb2 –Mg3 Bi2 alloys and the possibility of further improvement of thermoelectric performance was investigated. While the crystal structure of pure Mg3 As2 is different from Mg3 Sb2 and Mg3 Bi2, at least 15% arsenic solubility on the anion site (Mg3 ((Sb0.5 Bi0.5 )1− x As x )2 : x = 0.15) was confirmed. Density functional theory calculations showed the possibility of band convergence by alloying Mg3 Sb2 –Mg3 Bi2 with Mg3 As2 . Because of only a small detrimental effect on the charge carrier mobility compared to cation site substitution, the As 5% alloyed sample showed zT = 0.6–1.0 from 350 K to 600 K. This study shows that there is an even larger composition space to examine for the optimization of material properties by considering arsenic introduction into the Mg3 Sb2 –Mg3 Bi2 system.