Enhanced thermoelectric performance in polymorphic heavily Co-doped Cu₂SnS₃ through carrier compensation by Sb substitution

Abstract

2021): Enhanced thermoelectric performance in polymorphic heavily Co-doped Cu 2 SnS 3 through carrier compensation by Sb substitution, Science and Technology of Advanced Materials,

Effects of Preparation Procedures and Porosity on Thermoelectric Bulk Samples of Cu2SnS3 (CTS)

“…For samples TS2 (S ~250-400 µV/K, ρ ~1.5-1.1 mΩ-m) and TS3 (S ~325-425 µV/K, ρ ~3.5-1.5 mΩ-m), the TE measurements were repeatable during the measurement cycles, and the values of S and ρ were in agreement with the literature [7,15]. Although we observed an increased amount of SnO 2 and the formation of a new SnO phase, segregation of SnS was not observed.…”

“…In this temperature range, sulphides of copper and tin or copper and iron can be viable alternatives. Gu et al [14] discussed 3D modulation doping of CuCo 2 S 4 in CTS and reported a zT ~0.82 at 773 K. Zhao et al [15] reported simultaneous Co and Sb substitution in the CTS system resulting in a zT of ~0.88 at 773 K. Furthermore, Deng et al [16] reported a zT of ~1 in a similar Cu 7 Sn 3 S 10 system through Br-doping. A zT of ~0.4-0.8 above 700 K is regularly reported for CTS by In [17], Zn [7], Mn [18], Ni [19], Fe [20], Co [21], and Cu [22] substitution at the Sn site, aiming to enhance the carrier concentration and reduce the thermal conductivity.…”

Local-Disorder-Induced Low Thermal Conductivity in Degenerate Semiconductor Cu22Sn10S32

“…With the aim of decreasing the hole concentration while retaining the semiordering character of this phase beneficial for suppressing heat transport, we have investigated the aliovalent substitution of Sb 5+ for Sn 4+ , as reported recently in Cu 2 SnS 3 and Cu 3 SnS 4 . 8,57,58 We have fixed the pristine composition to that determined from synchrotron XRD data, i.e., Cu 22 Sn 10 S 32 corresponding to x = 0.063 in the Cu 2+x Sn 1−x S 3 series. For comparison purposes, we also include the thermoelectric properties of the x = 0.075 sample.…”

“…With the aim to decrease the hole concentration while retaining the semi-ordering character of this phase beneficial for suppressing the heat transport, we have investigated the aliovalent substitution of Sb 5+ for Sn 4+ , as reported recently in Cu2SnS3 and Cu3SnS4. 8,57,58 We have fixed the pristine composition to the one determined from synchrotron X-ray diffraction data, i. Cu26V2Ge6-xSbxS32. 56 As anticipated, the substitution of Sb for Sn in Cu22Sn10S32 results in a significant decrease in the hole concentration, reflected by the simultaneous increase in r and S.…”

Carrier-filtering and phonon-blocking AgSnSe2-decorated grain boundaries to boost the thermoelectric performance of Cu2Sn0.9Co0.1S3

“…CTS is a direct-gap semiconductor containing 3 bands derived from strongly hybridized Cu-3d and S-3p orbitals in the valence band edge and one single band from Sn-4s in the conduction band edge, which ensures a superior P-type TE performance as compared to N-types with a 3-dimensional Cu–S and S–S network as the transport channel for holes. 11,12 It has a very low κ l at high temperatures, particularly in the highly cation-disordered cubic and tetragonal phases, that is similar to its theoretical minimum of 0.3 W m −1 K −1 at 773 K. 7,13 By doping at the Sn site with transition metal atoms (Zn, 14 Ni, 15 Co, 7 Fe 16 ), CTS can be tuned to reach a wide carrier concentration, p , ranging from 10 19 to 10 21 cm −3 , with a large σ up to approximately 2000 S cm −1 (300 K), and a high PF up to 8–11 μW cm −1 K −2 at 723–773 K, despite the modest S . 7…”