Improving the zT value of thermoelectrics by nanostructuring: tuning the nanoparticle morphology of SbTe by using ionic liquids.

A systematic study on the microwave-assisted thermolysis of the single source precursor (EtSb)Te (1) in different asymmetric 1-alkyl-3-methylimidazolium- and symmetric 1,3-dialkylimidazolium-based ionic liquids (ILs) reveals the distinctive role of both the anion and the cation in tuning the morphology and microstructure of the resulting SbTe nanoparticles as evidenced by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and X-ray photoelectron spectroscopy (XPS). A comparison of the electrical and thermal conductivities as well as the Seebeck coefficient of the SbTe nanoparticles obtained from different ILs reveals the strong influence of the specific IL, from which CmimI was identified as the best solvent, on the thermoelectric properties of as-prepared nanosized SbTe. This work provides design guidelines for ILs, which allow the synthesis of nanostructured thermoelectrics with improved performances.