Computational modeling and measurement of thermal conductivity in bismuth telluride nanostructures and composites for thermoelectric applications

Thermoelectric materials are used in applications ranging from converting waste heat into usable electrical energy in industrial processes to generating electricity from radioactive heat sources in space. Their efficiency is quantified by the dimensionless figure of merit zT. Two pathways to improve zT are the engineering of structural features at the nanoscale and incorporating thermoelectrics into composites, both of which can reduce a material’s ability to transfer heat relative to the bulk, thereby decreasing thermal conductivity and enhancing zT. Bismuth telluride (Bi₂Te₃) is a room-temperature thermoelectric and experiments have shown that its nanostructured forms can exhibit reduced thermal conductivity. In this work, we employ molecular dynamics simulations to investigate zT in Bi₂Te₃ nanoparticles and Bi₂Te₃–Si₃N₄ composites to characterize phonon transport, surface effects, and interfacial resistance, quantifying how nanostructure and composite morphology influence thermal conductivity and assessing their potential impact on zT.