Insights into Interfacial Thermal Resistance in Bi₂Te₃/Graphene Composites for Thermoelectric Applications

Abstract

Bismuth telluride (Bi2Te3), a thermoelectric material, has gained tremendous attention for its high thermoelectric figure of merit (ZT) at room temperature. Recent experimental studies have demonstrated that incorporating graphene into Bi2Te3 can further enhance the ZT by reducing the thermal conductivity and increasing the power factor of the Bi2Te3/graphene composites. The interfacial thermal resistance (ITR) between Bi2Te3 and graphene plays a crucial role in determining the thermal conductivities of these composites. In the present study, we investigate the ITR between Bi2Te3 and graphene using nonequilibrium molecular dynamics simulations. We systematically explore the effects of graphene layer number, defects in graphene, and mechanical strain on the ITR. Our results reveal that the ITR increases with an increase in the number of graphene layers, reaching a stabilized value at five layers. Furthermore, the presence of vacancy defects in graphene reduces the ITR, with a higher defect density leading to greater reduction in the ITR. Remarkably, the mechanical strain has a profound impact on the ITR. At a tensile strain of 2.5%, the ITR more than quadruples, while a compressive strain of 4% reduces the ITR by about 60% compared to the strain-free condition. These findings offer valuable insights for manipulating the ITR in Bi2Te3/graphene composites with enhanced thermoelectric performance.