Enhanced thermoelectric performance of van der Waals Tellurium via vacancy engineering. (May 2021)

• Record Type: Journal Article
• Authors: Wang, Yuxi; Liu, Shuai; Wu, Zhen; Liu, Guoliang; Yang, Xin; Wei, Tianqi; Wang, Qianjin; Ye, Yu; Li, Deyu; Zhu, Jia
• Is Part Of: Materials today physics. Volume 18(2021)
• Publication Date: 2021-05
• Subjects: Two dimensional materials -- Tellurium -- Vacancy engineering -- Thermoelectric properties; Materials science -- Periodicals; Physics -- Periodicals; Electronic journals; 530.41
• DOI: 10.1016/j.mtphys.2021.100379
• Languages: English
• ISSNs: 2542-5293

Abstract

Abstract: Elemental doping is essential for tuning thermoelectric properties. However, effective doping has been a challenging task particularly for low dimensional materials. Here we demonstrate a vacancy-engineering strategy for effective doping to enhance thermoelectric properties of two-dimensional (2D) materials, using van der Waals tellurium as an example. Both Density Functional Theory (DFT) calculations and temperature dependent thermoelectric measurements confirm that annealing-induced vacancies can effectively shift the Fermi level into the valance band of individual 2D tellurium nanosheets, and consequentially increase the electrical conductivity significantly from 7 × 10 3 Sm −1 to 2.7 × 10 4 Sm −1 . As a result, this vacancy-engineering induced self-doping effect yields a state of art thermoelectric figure-of-merit ( ZT ) of 0.4 at 400 K. Therefore, our work provides an alternative and promising pathway for tuning the thermoelectric properties desirable for low dimensional materials. Graphical abstract: Image 1 Highlights: Vacancies generated in two-dimensional Tellurium nanosheets through annealing enable effective p-type doping. Density Functional Theory calculation verifies the effect of vacancy engineering. The shift of Fermi level into valance band increases carrier concentrations and thereby the power factor. A figure of merit as high as 0.4 is achieved at 400K via Vacancy engineering.