Synthesis, Bottom up Assembly and Thermoelectric Properties of Sb-Doped PbS Nanocrystal Building Blocks.

Doris Cadavid,Yu Liu,Aziz Genç,Alexey Shavel,Maria Ibáñez,Mengyao Li,Taisiia Berestok,Yu Zhang,George S Nolas,Andreu Cabot,Kaya Wei

doi:10.3390/ma14040853

Abstract

The precise engineering of thermoelectric materials using nanocrystals as their building blocks has proven to be an excellent strategy to increase energy conversion efficiency. Here we present a synthetic route to produce Sb-doped PbS colloidal nanoparticles. These nanoparticles are then consolidated into nanocrystalline PbS:Sb using spark plasma sintering. We demonstrate that the introduction of Sb significantly influences the size, geometry, crystal lattice and especially the carrier concentration of PbS. The increase of charge carrier concentration achieved with the introduction of Sb translates into an increase of the electrical and thermal conductivities and a decrease of the Seebeck coefficient. Overall, PbS:Sb nanomaterial were characterized by two-fold higher thermoelectric figures of merit than undoped PbS.

Highlights

To exploit the full potential of bottom-up strategies to produce functional nanomaterials, it is necessary to develop strategies to control the charge carrier concentration [1,2].introducing controlled amounts of electronic dopants into colloidal nanocrystals (NCs) has been often a main challenge
We demonstrate that Sb-doping in colloidal PbS NCs can be employed to tune the carrier concentration of bottom-up processed nanocrystalline materials
PbS NCs were highly monodisperse and displayed a cubic morphology. Their size could be controlled in the range from 8 nm to 12 nm by changing the reaction temperature from 130 ◦ C to 210 ◦ C

Summary

Introduction

To exploit the full potential of bottom-up strategies to produce functional nanomaterials, it is necessary to develop strategies to control the charge carrier concentration [1,2].introducing controlled amounts of electronic dopants into colloidal nanocrystals (NCs) has been often a main challenge. To exploit the full potential of bottom-up strategies to produce functional nanomaterials, it is necessary to develop strategies to control the charge carrier concentration [1,2]. A particular application, where such electronic doping is key and where the use of nanomaterials presents a clear advantage, is thermoelectricity [3,4,5,6]. Electrical conductivity (σ), Seebeck coefficient (S) and thermal conductivity (κ), strongly depend on charge carrier concentration. While σ increases with charge carrier concentration, improving the thermoelectric figure of merit ZT = σS2 /κ, S decreases and the electronic contribution to κ increases, both having a detrimental effect on ZT [7,8]. A precise adjustment of the carrier concentration is necessary to optimize the material’s thermoelectric properties

Methods

Results

Conclusion