Janus TaOClBr monolayer: A promising multifunctional material with high solar-to-hydrogen efficiency and strong anisotropic thermoelectric performance

Abstract

Based on first-principles calculations and Boltzmann transport theory, we have systematically investigated the photocatalytic and thermoelectric properties of the two-dimensional Janus TaOClBr monolayer. The Janus TaOClBr is found to be thermally, dynamically, and mechanically stable. The electronic structure indicates that the Janus TaOClBr unfolds semiconductor character with an indirect bandgap of 1.91 eV. It is found that the Janus TaOClBr can serve as a potential photocatalyst for water splitting in an acidic environment. Moreover, the Janus TaOClBr possesses a high corrected solar-to-hydrogen efficiency η'STH of 15.93% at pH = 0. The lattice thermal conductivity Kl of the Janus TaOClBr at 300 K along the x- and y-directions is 4.05 and 5.26 W/(m K), respectively, exhibiting anisotropic thermal transport. The Janus TaOClBr exhibits a strongly anisotropic charge mobility and has a high electron mobility of 939.53 cm2 V−1 s−1 in the y-direction. The maximum ZT value of the n-type doping for the Janus TaOClBr can reach 0.86 and 1.63 at 600 and 900 K, respectively. The results show that the Janus TaOClBr is not only a promising photocatalyst for water splitting, but also a good n-type thermoelectric material at high temperatures. Our study reveals that the Janus TaOClBr can be used as a promising multifunctional energy conversion material.