Morphological investigations on the growth of defect-rich Bi2Te3 nanorods and their thermoelectric properties

Abstract

Bi₂Te₃ nanorods (NRs) have been successfully synthesized at different reaction temperatures via a surfactant-assisted hydrothermal method. The experimental observations revealed that the reaction temperature, SDBS surfactant (sodium dodecylbenzene sulphonate) and its concentration affect the morphology of Bi₂Te₃. It is identified that an imperfect oriented attachment mechanism is the dominant growth mechanism for the evolution of Bi₂Te₃ NRs. Moreover, a subsidiary growth mechanism namely the Oswald ripening process could also affect the Bi₂Te₃ NR growth process at higher reaction temperatures. Thermoelectric property measurements revealed that flake-decorated Bi₂Te₃ NRs achieved the maximum power factor value of ∼1.32 μW cm⁻¹ K⁻² at 410 K, which was higher than those of porous and smooth Bi₂Te₃ NRs. Such an enhancement in the power factor of flake-decorated Bi₂Te₃ NRs is primarily attributed to their outstanding electrical conductivity at 410 K.