Combination of Carrier Concentration Regulation and High Band Degeneracy for Enhanced Thermoelectric Performance of Cu₃SbSe₄

Abstract

The effect of Al-, Ga-, and In-doping on the thermoelectric (TE) properties of CuSbSe has been comparatively studied on the basis of theoretical prediction and experimental validation. It is found that tiny Al/Ga/In substitution leads to a great enhancement of electrical conductivity with high carrier concentration and also large Seebeck coefficient due to the preserved high band degeneracy and thereby a remarkably high power factor. Ultimately, coupled with the depressed lattice thermal conductivity, all three elements (Al/Ga/In) substituted samples have obtained a highly improved thermoelectric performance with respect to undoped CuSbSe. Compared to the samples at the same Al/In doping level, the slightly Ga-doped sample presents better TE performance over the wide temperature range, and the CuSbGaSe sample presents a record high ZT value of 0.9 among single-doped CuSbSe at 623 K, which is about 80% higher than that of pristine CuSbSe. This work offers an alternative approach to boost the TE properties of CuSbSe by selecting efficient dopant to weaken the coupling between electrical conductivity and Seebeck coefficient.

Thermoelectric Properties of Doped-Cu3SbSe4 Compounds: A First-Principles Insight

“…TE properties of Cu 3 SbSe 4 compound have been extensively studied. [15][16][17][19][20][21][22][25][26][27][28][29]56,57 As discussed below, our results are in agreement with experimental data. TE parameters are evaluated for T = 300−900 K and hole carrier concentrations (p) between 1 × 10 18 and 1 × 10 21 cm −3 (see Figure 5), which are considered as the optimum working ranges for TE materials.…”

Polymeric Thermoelectric Composites by Polypyrrole and Cheap Reduced Graphene Oxide in Towel-Gourd Sponge Fibers

“…The S of PDMS/TS-rGO composites decreases monotonically from 26.4 to 16.9 μV/K with filler loading. This tendency is in accordance with bulk semiconducting materials whose S often declines while their σ rises . For PDMS/TS-rGO-PPy composite samples, S increases monotonically from 39.0 to 84.2 μV/K with filler loading.…”

Band Engineering for Realizing Large Effective Mass in Cu3SbSe4 by Sn/La Codoping

“…DFT was employed by using the projector augmented wave (PAW) method , and the Perdew–Burke–Ernzerhof (PBE) generalized gradient approximation (GGA) on the Vienna ab initio simulation package (VASP), and the relatively large Hubbard-like term (+U, ∼15 eV) of d -electrons on Cu atoms is needed to obtain the accurate band gap for the 2 × 2 × 1 supercells of Cu 3 SbSe 4 here. ,, One Sb atom was replaced by a Sn or La atom in the calculation for the doping samples (Cu 3 Sb 1– x Sn x Se 4 and Cu 3 Sb 1– y La y Se 4 ). A cutoff energy of 400 eV, a Monkhorst–Pack k -mesh of 6 × 6 × 6, and an energy conversion threshold of 10 –5 eV were also used.…”

“…5,9,14 However, intrinsic Cu 3 SbSe 4 cannot be used for commercial applications owing to its low hole carrier concentration (n H ). Therefore, both of the theoretical 34,35 and experimental [22][23][24][25][26][27][28][29][30][31][32][33]36 research studies successfully optimized the n H of Cu 3 SbSe 4 by doping group IIIA 23−25 or IVA 27−29 elements at Sb sites. Especially by doping with the Sn element, as a perfect p-type doping in the Cu 3 SbSe 4 system, Sn has nearly 100% doping efficiency 29 due to its similar atomic structure and the absent of one outer electron compares with Sb.…”

“…Cu 3 SbSe 4 , belonging to a member of the typical copper-based chalcogenides, has a complex crystal structure (which results in a very low intrinsic κ tot ) and high S , both of which make it a competitive p -type thermoelectric material in a medium-temperature range. − In addition, its abundance in the earth and environmentally friendly properties make it an effective alternative for the most common medium-temperature thermoelectric material PbTe. ,, However, intrinsic Cu 3 SbSe 4 cannot be used for commercial applications owing to its low hole carrier concentration ( n H ). Therefore, both of the theoretical , and experimental − , research studies successfully optimized the n H of Cu 3 SbSe 4 by doping group IIIA − or IVA − elements at Sb sites. Especially by doping with the Sn element, as a perfect p -type doping in the Cu 3 SbSe 4 system, Sn has nearly 100% doping efficiency due to its similar atomic structure and the absent of one outer electron compares with Sb.…”