The regulation of thermoelectric transport in Janus1T-In2OSe monolayer with biaxial tensile strain

Abstract Tensile strain, 1T-In2OSe monolayerAbstractAs an effective regulation method, applying strain to materials has become a widelyrecognized reversible regulatory strategy. However, to date, using strain to regulate thethermal transport properties of two-dimensional Janus materials has rarely beenreported. In this study, combining the first-principles calculations with Boltzmann transport theory, we provide an insight into the physical mechanism of thermoelectric property regulation of 2D Janus 1T-In2OSe monolayer by biaxial tensile strain. The analysis of phonon spectrum proves that the 1T-In2OSe monolayer is dynamically stable. The biaxial tensile strain can change the size and type of bandgap, thereby altering the electrical transport properties. Under 8% biaxial tensile strain, the high Seebeck coefficient of 1334 μV/K with highest power factor 2.8×1011 W/K2·m·s, achieving high conductivity. After applying strain, phonons exhibit significant softening, resulting in a decrease in lattice thermal conductivity from 1.21 W/mK to 0.31 W/mK. The reason is that the increasing strain leads to enhanced phonon-phonon scattering. Notably, the figure of merit of 1T-In2OSe monolayer can reach 3.42 at 800 K and 8% biaxial tensile strain, which is superior to many reported 2D thermoelectric materials. The present work demonstrates that 1T-In2OSe monolayer is a promising high-temperature thermoelectric material.