As-based ternary Janus monolayers for efficient thermoelectric and photocatalytic applications

Highly efficient and sustainable energy resources are in great demand today to combat environmental pollution and the energy crisis. In this study, we examined the novel 2D Janus AsTeX (X = Cl, Br and I) monolayers using first-principles calculations and explored their potential energy conversion applications. We demonstrated the thermal, energetic, dynamic and mechanical stability of AsTeX (X = Cl, Br, and I) monolayers. Janus AsTeX (X = Cl, Br and I) monolayers are indirect bandgap semiconductors with high carrier mobilities and excellent visible light optical absorption. Our findings demonstrate that Janus AsTeCl and AsTeBr monolayers exhibit low lattice thermal conductivity and excellent electronic transport properties obtained using semi-classical Boltzmann transport theory, including various scattering mechanisms. Additionally, the redox potential of water is adequately engulfed by the band alignments of the AsTeCl and AsTeBr monolayers. The water splitting process under illumination can proceed spontaneously on the Janus AsTeBr monolayer, while minimal low external potential (ranging from 0.26-0.29 eV) is required to trigger the water splitting process on the Janus AsTeCl monolayer. More than 10% STH efficiency of these monolayers indicates their potential practical applications in the commercial production of hydrogen. Thus, our study demonstrates that these monolayers can show potential applications in energy conversion fields.