Journal
ACS APPLIED MATERIALS & INTERFACES
Volume 12, Issue 28, Pages 31619-31627Publisher
AMER CHEMICAL SOC
DOI: 10.1021/acsami.0c07566
Keywords
thermoelectric; Bi2Te3; point defect; band degeneracy; alloying scattering
Funding
- National Natural Science Foundation of China [51701126]
- Shenzhen Science and Technology [JCYJ20180305124020928]
- Guangdong Basic and Applied Basic Research Foundation [2019A1515010832]
- Natural Science Foundation of SZU [860-000002110289]
- Foundation for Distinguished Young Talents in Higher Education of Guangdong, China [2017KQNCX178]
- National Postdoctoral Program for Innovative Talents [BX201600110]
- Shenzhen Clean Energy Research Institute
Ask authors/readers for more resources
For decades, the V2VI3 compounds, specifically p-type Bi2-xSbxTe3 and n-type Bi2Te3-xTe3, have remained the cornerstone of commercial thermoelectric solid-state cooling and power generation near room temperature. However, a long-standing problem in V2VI3 thermoelectrics is that n-type Bi2Te3-xSex is inferior in performance to p-type Bi2-xSbxTe3 near room temperature, restricting the device efficiency. In this work, we developed high-performance n-type Bi2-xSbxTex, a composition long thought to only make good p-type thermoelectrics, to replace the mainstream n-type Bi2Te3-xSex. The success arises from the synergy of the following mechanisms: (i) the donorlike effect, which produces excessive conduction electrons in Bi2Te3, is compensated by the antisite defects regulated by Sb alloying; (ii) the conduction band degeneracy increases from 2 for Bi2Te3 and Bi2Te3-xSx to 6 for Bi2-xSbxTe3, favoring high Seebeck coefficients; and (iii) the larger mass fluctuation yet smaller electronegativity difference and smaller atomic radius difference between Bi and Sb effectively suppresses the lattice thermal conductivity and retains decent carrier mobility. A state-of-the-art zT of 1.0 near room temperature was attained in hot deformed Bi1.5Sb0.5Te3, which is higher than those for most known n-type thermoelectric materials, including commercial Bi2Te3-xSex ingots and the popular Mg3Sb2. Technically, building both the n-leg and p-leg of a thermoelectric module using similar chemical compositions has key advantages in the mechanical strength and the durability of devices. These results attested to the promise of n-type Bi2-xSbxTe3 as a replacement of the mainstream n-type Bi2Te3-xSex near room temperature.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available