X2Pd3Se4 (X = K, Rb, Cs): Unexplored 2D semiconductors with high n-type transport performance

• Published in: FlatChem 2023-03, Vol.38, p.100482, Article 100482
• Main Authors: Sheng, Xiaofei, Zhang, Pengcheng, Bao, Lei, Dun, Yapeng, Gao, Shen, Rao, Xiaoxiao, Yao, Cenglin, Kang, Wenbin
• Format: Article
• Language: English
• Subjects: 2D materials; Carrier mobility; Thermal conductivity; Thermoelectric figure of merit; X2Pd3Se4
• ISSN: 2452-2627; 2452-2627
• DOI: 10.1016/j.flatc.2023.100482

[Display omitted] •Monolayer X2Pd3Se4 (X = K, Rb, Cs) are indirect bandgap semiconductors with band-gaps of 1.74 ∼ 1.95 eV.•The show “multi-valleys” convergence near conduction band minimums.•They possess high ZT values of 0.20 ∼ 1.04 at 300 K, and 0.67 ∼ 1.94 at 700 K. Two-dimensional (2D) materials have attracted much interest because of their special morphology and novel physical properties. In this work, we proposed three unexplored 2D materials, X2Pd3Se4 (X = K, Rb, Cs), and further investigated their stability, electronic and thermoelectric transport properties. We revealed that these materials are indirect semiconductors with band-gaps of 1.74 ∼ 1.95 eV, and show “multi-valleys” convergence near conduction band minimums. Besides, the monolayers also possess high electron mobility of 103 ∼ 104 cm2·V−1·s−1, leading to high conductivity (106 ∼ 107 Ω-1m−1), as well as high thermoelectric power factor (∼102 mW·K−2·m−1). Also, because of the high group velocity and low phonon scattering rate, they also show moderate lattice thermal conductivity of 19.21 ∼ 75.78 W/mK at 300 K. Nevertheless, they still deliver high thermoelectric figure of merit of 0.20 ∼ 1.04 at 300 K, and increase further to 0.67 ∼ 1.94 at 700 K, suggesting that they have potential applications in the field of low-medium temperature thermoelectric devices.