The role of electronegativity in the thermoelectric performance of GeTe–I–V–VI2 solid solutions. Issue 4 (12th January 2021)

• Record Type: Journal Article
• Authors: Li, Nanhai; He, Wenlu; Li, Chengjun; Wang, Guiwen; Wang, Guoyu; Zhou, Xiaoyuan; Lu, Xu
• Is Part Of: Journal of materials chemistry. Volume 9:Issue 4(2021)
• Page Start: 2385
• Page End: 2393
• Publication Date: 2021-01-12
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d0ta10268g
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : The influence of the average electronegativity difference between the alloying atom and host atom on alloy scattering potential and thus carrier mobility is studied. Abstract : GeTe-based solid solutions, exemplified by GeTe–AgSbTe2 (TAGS), have revealed superior thermoelectric performance in the past few decades. Recently, alloying GeTe with other compounds in the I–V–VI2 family has been employed as an effective means to further enhance figures-of-merit. The following work has systematically investigated the alloying effect of I–V–VI2 compounds (I = Cu and Na; V = Sb and Bi; VI = Te) on the thermoelectric performance of GeTe. It has been found that all these alloying compounds can synergistically optimize the carrier concentration and reduce lattice thermal conductivity, which boosts the figure-of-merit for GeTe. More importantly, this work has demonstrated that the electronegativity difference between group I elements and Ge determines the alloy scattering potential and thus carrier mobility. As a result, compounds with nominal compositions of (GeTe)0.92 (NaSbTe2 )0.08 and (GeTe)0.92 (CuSbTe2 )0.08 have achieved zT s of ∼1.30 and 1.58 at 773 K, respectively. Our work highlights the importance of electronegativity in thermoelectric GeTe-based solid solutions and thus provides valuable guidance for designing novel thermoelectric materials.