Novel ternary sulfide thermoelectric materials from high throughput transport and defect calculations

Abstract

Predicting a novel thermoelectric material requires the simultaneous optimization of several different factors. In this work we use two material design strategies to identify a new n-doped ternary sulfide thermoelectric using a high throughput framework. We have investigated a total of 234 ternary sulfides.Out of these, we identify five candidates that are thermodynamically stable and have bandstructures leading to favourable transport properties. We then predict the likelihood of n-doping, based on a high throughput defect analysis that characterizes the stability of the most favorable compensating intrinsic defects. This proved to be a crucial step which filters only one candidate without any stable electron killer defects. We also explore the possibility of improving the thermoelectric properties with thermal expansion, resulting in carrier pocket alignment. We demonstrate that in CoSbS several positive factors are simultaneously effective, i.e. good thermoelectric properties, correct bandgap, no intrinsic doping limit and an alignment of carrier pockets with volume increase.

Strong Reduction of Thermal Conductivity and Enhanced Thermoelectric Properties in CoSbS1-xSex Paracostibite

“…These were followed by band structure calculations on a fine k-mesh of 64 × 10 6 /V_unitcell. DFT band structures were evaluated using Engel-Vosko(EV) functional 29 , which were demonstrated to estimate the bandgaps quite accurately(compared to standard LDA/GGA) for thermoelectric materials with very low computational costs 30 .…”

Low-Temperature Thermopower in CoSbS

“…Co 1−x Ni x SbS and CoSbS 1−x X x (X=Se,Te) showed figure of merit ZT = (0.5 − 0.62) in (730-900) K range and high power factor [18][19][20]. Moreover, even higher values of ZT > 1 at 600 K have been predicted by density functional theory in optimized CoSbS-based materials [21].…”

Enhancing the thermoelectric performance of Cu3SnS4-based solid solutions through coordination of the Seebeck coefficient and carrier concentration

“…43 In order to better understand the band structure alterations, we present the Pisarenko plots 21 in Fig.8a, assuming m* unpinning (Fig.5b) (2) and (3). But it is obvious that such estimations could not change the tendency described in Fig.8(b).…”