Enhanced thermoelectric performance of van der Waals Tellurium via vacancy engineering

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 x 10(3) Sm-1 to 2.7 x 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. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

Elemental doping is essential for tuning thermoelectric properties. Effective doping has been achieved using a vacancy-engineering strategy for two-dimensional materials, such as van der Waals tellurium. This approach improves the thermoelectric properties significantly, demonstrating a promising pathway for tuning thermoelectric properties in low dimensional materials.