Shashlik-like Te–Bi2Te3 hetero-nanostructures: one-pot synthesis, growth mechanism and their thermoelectric properties

Abstract

Shashlik-like Te–Bi₂Te₃ nanocomposites (consisting of Te nanorods and Bi₂Te₃ nanoplates) were successfully synthesized via a solvothermal method. Te nanorods first appear in the solvent followed by the formation of Bi₂Te₃ nanoplates on the surface of the Te nanorods. The lattice parameters of the Te phase and Bi₂Te₃ phase are almost identical (a_Bi2Te3 ≈ a_Te3, c_Bi2Te3 ≈ 5c_Te), resulting in the epitaxial growth of the nanoplates and ultimately forming the shashlik-like structure. With increasing reaction time, the Te nanorods were gradually dissolved, and only the pure Bi₂Te₃ nanoplates remained. The effect of different reaction times on crystal growth and the morphology evolution of products are extensively discussed. The Te–Bi₂Te₃ hetero-nanostructure powders were then densified into a bulk material by a spark plasma sintering technique, showing a promising figure of merit (ZT) value (0.54, 398 K). This study explores and provides a reliable one-pot method to synthesize novel shashlik-like Te–Bi₂Te₃ for application of high-performance thermoelectric materials.