Role of interlayer coupling for the power factor ofCuSbS2andCuSbSe2

Abstract

The electronic and transport properties of bulk and monolayer CuSbS 2 and CuSbSe 2 are determined by using density functional theory and semiclassical Boltzmann transport theory, in order to investigate the role of interlayer coupling for the thermoelectric properties. The calculated band gaps of the bulk compounds are in agreement with experiments and significantly higher than those of the monolayers, which thus show lower Seebeck coefficients. Since also the electrical conductivity is lower, the monolayers are characterized by lower power factors. Therefore, interlayer coupling is found to be essential for the excellent thermoelectric response of CuSbS 2 and CuSbSe 2 , even though it is weak.

Copper—antimony and copper—bismuth chalcogenides—Research opportunities and review for solar photovoltaics

“…(i) CuSbS 2 : Gudelli's theoretical evaluation 205 suggests that p-type will perform better than n-type, which is just as well since it is naturally p-type. Further theory from Alsaleh 283 highlights the role of interlayer coupling in thermal conductivity and also for CuSbSe 2 .…”

Exceptional Thermoelectric Properties of Layered GeAs2

“…The latter exhibits strong layer-dependent electronic , and vibrational properties. , For example, platinum disulfide (PtS 2 ) has been reported to possess a nearly isotropic in-plane and out-of-plane mechanical interlayer coupling due to quasicovalent bonding formed by strong orbital hybridization of interlayer sulfur atoms . Similarly, the well-known direct to indirect band gap transition in MoS 2 arises from the Coulomb repulsion between the sulfur atoms in adjacent layers. , These results imply that strong quasicovalent bonding, rather than pure vdW force, is primarily responsible for some of the distinctive electronic − and mechanical properties , of these materials.…”

Excellent Thermoelectric Performance of 2D CuMN2 (M = Sb, Bi; N = S, Se) at Room Temperature

“…As shown in Figure S3 , SOC has a non-ignorable impact on band structure, especially for CuBiS 2 and CuBiSe 2 , so SOC was all considered in following calculations. As shown in Figure 3 , all the monolayers are narrow band-gap semiconductors with band gaps of 0.57~1.10 eV, which are slightly smaller than or comparable to their bulk structures [ 21 , 23 , 45 , 46 ]. Since the valence band maximum (VBM) and conduction band minimum (CBM) are both located at Γ point, both CuSbS 2 , CuSbSe 2 , and CuBiS 2 belong to direct bandgap semiconductors.…”

“…[ 21 ] Among them, CuSbS 2 exhibited the low lattice thermal conductivity of about 1.5~2 W/mK [ 22 ]. Additionally, both bulk and monolayer CuSbS 2 and CuSbSe 2 were revealed to have an excellent thermoelectric power factor at 300 K, reaching about 0.2~1.0 mW/mK 2 at constant relaxation time approximation (CRTA) of 11 fs [ 23 ]. Therefore, it is of high interest to see whether or not the monolayer CuSbS 2 , CuSbSe 2 , CuBiS 2 , and CuBiSe 2 , can also deliver good thermoelectric performance.…”