Investigations on the thermoelectric and thermodynamic properties of Y2CT2 (T = O, F, OH).

ABSTRACT

Using the first-principle calculations combined with the Boltzmann transport theory, we studied the thermoelectric properties of Y2CT2 (T = O, F, OH) MXenes. Specifically, the Seebeck coefficient, thermal and electrical conductivities under constant relaxation time approximation were calculated. Results show that for p-type carriers, Y2CO2 has the largest power factor of up to 0.0017 W m-1 K-2 when the carrier concentration is 4.067 × 1013 cm-2 at 900 K, at the same temperature, for n-type carriers, the concentration is 9.376 × 1013 cm-2, the power factor in Y2C(OH)2 is 0.0026 W m-1 K-2. In particular, the figure of merit in Y2CF2 is 1.38 at 900 K because of its low thermal conductivity, indicating that it can be considered a potential medium-temperature thermoelectric material. In addition, the thermodynamics properties within 32 GPa and 900 K, such as bulk modulus, heat capacity and thermal expansion, are also estimated using the quasi-harmonic Debye model. Our results may offer some valuable hints for the potential application of Y2CT2 (T = O, F, OH) in the thermoelectric field.