AUTHOR=Li Lei , Huang Zhuqin , Xu Jinqi , Huang Haihua 

TITLE=Theoretical analysis of the thermoelectric properties of penta-PdX2 (X = Se, Te) monolayer

JOURNAL=Frontiers in Chemistry

VOLUME=10

YEAR=2022

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2022.1061703

DOI=10.3389/fchem.2022.1061703

ISSN=2296-2646

ABSTRACT=<p>Based on the successful fabrication of PdSe<sub>2</sub> monolayers, the electronic and thermoelectric properties of pentagonal PdX<sub>2</sub> (X = Se, Te) monolayers were investigated <italic>via</italic> first-principles calculations and the Boltzmann transport theory. The results showed that the PdX<sub>2</sub> monolayer exhibits an indirect bandgap at the Perdew–Burke–Ernzerhof level, as well as electronic and thermoelectric anisotropy in the transmission directions. In the PdTe<sub>2</sub> monolayer, P-doping owing to weak electron–phonon coupling is the main reason for the excellent electronic properties of the material. The low phonon velocity and short phonon lifetime decreased the thermal conductivity (<italic>κ</italic><sub>l</sub>) of penta-PdTe<sub>2</sub>. In particular, the thermal conductivity of PdTe<sub>2</sub> along the x and y transmission directions was 0.41 and 0.83 Wm<sup>−1</sup>K<sup>−1</sup>, respectively. Owing to the anisotropy of <italic>κ</italic><sub>l</sub> and electronic structures along the transmission direction of PdX<sub>2</sub>, an anisotropic thermoelectric quality factor <italic>ZT</italic> appeared in PdX<sub>2</sub>. The excellent electronic properties and low lattice thermal conductivity (<italic>κ</italic><sub>l</sub>) achieved a high <italic>ZT</italic> of the penta-PdTe<sub>2</sub> monolayer, whereas the maximum <italic>ZT</italic> of the p- and n-type PdTe<sub>2</sub> reached 6.6 and 4.4, respectively. Thus, the results indicate PdTe<sub>2</sub> as a promising thermoelectric candidate.</p>