High Thermoelectric Performance in Two-Dimensional Tellurium: An Ab Initio Study

Abstract

In 2016, bulk tellurium was experimentally observed as a remarkable thermoelectric material. Recently, two-dimensional (2D) tellurium, called tellurene, has been synthesized and has exhibited unexpected electronic properties compared with the 2D MoS 2 . They have also been fabricated into air-stable and high efficient field-effect transistors. There are two stable 2D tellurene phases. One (β-Te) has been confirmed with an ultralow lattice thermal conductivity (κ L ). However, the study of the transport properties of the other more stable phase, α-Te, is still lacking. Here, we report the thermoelectric performance and phonon properties of α-Te using Boltzmann transport theory and first principle calculations. A maximum ZT value of 0.83 is achieved under reasonable hole concentration, suggesting that the monolayer α-Te is a potential competitor in the thermoelectric field.

Thermoelectric Penta-Silicene with a High Room-Temperature Figure of Merit

“…It has been used to explain many prominent thermoelectric performances, such as Na x CoO 2 , 53 SnSe, 55 PbTe 1−x Se x , 12 and tellurium. 42 The ultrahigh PF of penta-silicene is derived from four hole pockets and relatively flat bands with the same spirit of "puddingmold" shown in Figure 2c…”

Abnormally low thermal conductivity of 2D selenene: An ab initio study

“…The group velocities are quite small, comparable to those of 2D SnSe, arsenene and stanene, [32][33][34][35][36]39 but larger than α-tellurene. 17 The Debye temperature θD is larger than 2D…”

“…The lattice thermal conductivity of α-selenene is investigated by using first-principles calculations theoretically, based on Boltzmann transport equation (BTE). It is found αselenene possesses a quite low κL of 3.04 W m -1 K -1 , lower than that of α-tellurene, 17 which has similar structure and lower Debye temperature. This abnormal phenomenon reasonably stems from the stronger anharmonicity of acoustic phonons compared with the α-tellurene, as shown by Grüneisen parameters.…”

“…Furthermore, thermoelectric property is a hot research focusing of 2D materials, since a great number of 2D materials show high thermoelectric performance. [17][18][19][20][21][22][23] It is well known that low thermal conductivity is very important for thermoelectric materials, since the figure of merit zT, which is used to measure the thermoelectric efficiency, is inversely proportional to thermal conductivity.…”

“…For instance, theoretical investigation shows α-tellurene processes high zT as the low κL. 17 Thus, the investigation of κL is an urgent need for the potential application of α-selenene 3 as a thermoelectric material.…”