ZT enhancement in solution-grown Sb(2-x)Bi(x)Te3 nanoplatelets

TL;DR

This study presents a solution-based synthesis of Sb(2-x)Bi(x)Te3 nanoplatelets, which after processing, exhibit significantly improved thermoelectric performance due to nanostructuring that reduces thermal conductivity and enhances the figure of merit.

Contribution

It introduces a novel ligand-supported synthesis method for Sb(2-x)Bi(x)Te3 nanoplatelets and demonstrates their enhanced thermoelectric properties after processing.

Findings

Thermal conductivity reduced by 60% in nanostructured bulk.

Thermoelectric figure of merit increased by up to 15%.

Maximum thermoelectric performance shifted to higher temperatures.

Abstract

We report a solution-processed, ligand supported synthesis of 15-20 nm thick Sb(2-x)Bi(x)Te3 nanoplatelets. After complete ligand removal by a facile NH3-based etching procedure, the platelets are spark plasma sintered to a p-type nanostructured bulk material with preserved crystal grain sizes. Due to this nanostructure, the total thermal conductivity is reduced by 60 % in combination with a reduction in electric conductivity of as low as 20 % as compared to the bulk material demonstrating the feasibility of the phonon-glass electron-crystal concept. An enhancement in the dimensionless thermoelectric figure of merit of up to 15 % over state-of-the-art bulk materials is achieved meanwhile shifting the maximum to significantly higher temperatures.