Potential for high thermoelectric performance in n-type Zintl compounds: a case study of Ba doped KAlSb4. Issue 8 (1st February 2017)

• Record Type: Journal Article
• Authors: Ortiz, Brenden R.; Gorai, Prashun; Krishna, Lakshmi; Mow, Rachel; Lopez, Armando; McKinney, Robert; Stevanović, Vladan; Toberer, Eric S.
• Is Part Of: Journal of materials chemistry. Volume 5:Issue 8(2017)
• Page Start: 4036
• Page End: 4046
• Publication Date: 2017-02-01
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c6ta09532a
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : High-throughput computational assessment of Zintl compounds reveals that n-type materials potentially outnumber and outperform p-type counterparts; n-type KAlSb4 reinforces the calculated results. Abstract : High-throughput calculations (first-principles density functional theory and semi-empirical transport models) have the potential to guide the discovery of new thermoelectric materials. Herein we have computationally assessed the potential for thermoelectric performance of 145 complex Zintl pnictides. Of the 145 Zintl compounds assessed, 17% show promising n-type transport properties, compared with only 6% showing promising p-type transport. We predict that n-type Zintl compounds should exhibit high mobility μ n while maintaining the low thermal conductivity κ L typical of Zintl phases. Thus, not only do candidate n-type Zintls outnumber their p-type counterparts, but they may also exhibit improved thermoelectric performance. From the computational search, we have selected n-type KAlSb4 as a promising thermoelectric material. Synthesis and characterization of polycrystalline KAlSb4 reveals non-degenerate n-type transport. With Ba substitution, the carrier concentration is tuned between 10 18 and 10 19 e − cm −3 with a maximum Ba solubility of 0.7% on the K site. High temperature transport measurements confirm a high μ n (50 cm 2 V −1 s −1 ) coupled with a near minimum κ L (0.5 W m −1 K −1 ) at 370 °C. Together, these properties yield a zT of 0.7 at 370 °C for the composition K0.99 Ba0.01 AlSb4 . Based on the theoretical predictions and subsequent experimental validation, we find significant motivation for the exploration of n-type thermoelectric performance in other Zintl pnictides.