Enhanced Thermoelectric Performance of Nanostructured Cu₂SnS₃ (CTS) via Ag Doping

Abstract

The present work aims to investigate the effect of Ag doping on the thermoelectric properties of Cu2SnS3 (CTS). Various Cu2Ag(x)Sn(1–x)S3 (0.05 ≤ x ≤ 0.25) samples were synthesized by mechanical alloying followed by spark plasma sintering, and their structural and transport properties were systematically investigated. The x = 0.15 sample presented a ∼10-fold higher power factor than the undoped CTS. Although, the x = 0.125 sample had a lower power factor than the x = 0.15 sample, owing to its lower thermal conductivity, both the samples showed the highest zT ∼ 0.8 at 723 K. This value is comparable to the best results available in the literature for earth-abundant and eco-friendly thermoelectric materials. Interestingly, the thermal conductivity of Cu2Ag(x)Sn(1–x)S3 samples increased with Ag substitution, which was further investigated using the first-principles and ab initio molecular dynamics calculations. It was observed that the incorporation of Ag into the system decreases the root mean square displacement of the other cations and anions, reducing the scattering of phonons and thereby increasing the lattice thermal conductivity. Moreover, the calculations on the formation energy have revealed the reason for the structural transformation of CTS and similar diamond-like structures toward high symmetry polymorphs by external doping. The increase in zT is directly related to the optimization of the band gap and the weighted mobility, which have been investigated experimentally and using the first principle method.

High Thermoelectric Performance in Cu2SnS3 by Control Over Phase‐Dependent Mobility Edge

“…[17] Cu 2 SnS 3 , as representative of TE sulfides, possesses ordered monoclinic, disordered cubic and tetragonal phases, providing an idea platform to study the influence of disorder on the electrical and thermal transport properties of TE composites. [18][19][20] Up to now, the electrical and thermal transport properties of Cu 2 SnS 3 have been intensively investigated. For example, Wei et al synthesized tetragonal Cu 2 SnS 3 by In doping using a colloidal synthesis method, and obtained a low thermal conductivity due to plenty of twin boundaries.…”

High-Performance Paper-Based Thermoelectric Generator from Cu2SnS3 Nanocubes and Bulk-Traced Bismuth

“…A high output power of ∼2.2 μW at Δ T = 80 K is obtained from such a 20-pair CTS-p and Bi-n PTEG assembled on a flexible Kapton sheet, and the experimental results are validated by multiphysics device modeling. While only a handful of literature reports are available on the synthesis and TE properties exploration in phase-pure bulk and nanocrystalline CTS, ,− there is currently no report where CTS is studied as an efficient TE material in a flexible TEG. Furthermore, the constructed PTEG using CTS as one of the TE leg materials when paired with traced bulk Bi-leg showed the ability to harvest waste heat energy from the exhaust of a motorbike demonstrating the proof-of-concept utility of the 20 p–n pair PTEG, resulting in a reasonable output power of 42 nW at Δ T = 20 K.…”

Controllability study of copper‐tin‐sulphide (Cu3SnS4) material based on the ratio adjustment of Cu to Sn elements

“…The copper tin sulphide (Cu 3 SnS 4 , Cu 2 SnS 3 etc. ), is one of the representatives of Cu‐Sn‐S ternary chalcogenides and a direct band gap P‐type semiconductor material [1–8]. Copper tin sulphide has broad application prospects in photoelectric [9–11], thermoelectric [12, 13], photocatalysis [14–17], non‐linear optics, electrode materials [18], hydrophobicity, gas‐sensitive materials [19], adsorption in the light and electromagnetic wave[20–22] and so on.…”

“…Physical methods include the vacuum evaporation method [37–39], mechanical alloy method [40, 41], magnetron sputtering method [42–45] etc. To investigate the effect of Ag doping on the thermoelectric properties of CTS, Lohani, Nautiyal [5] synthesize various Cu 2 Ag ( x ) Sn (1− x ) S 3 (0.05 ≤ x ≤ 0.25) samples by mechanical alloying followed by spark plasma sintering, and their structural and transport properties were systematically investigated. Chemical methods include: spray pyrolysis [2, 46–50], continuous ion layer adsorption and reaction [51, 52], sealed tube solid state reaction [53], solution method [54–56], hot injection method [57–59], template synthesis method [60, 61], the solvothermal method [30, 32, 35, 62–69], microwave method [70, 71], liquid phase reflux method [72, 73], chemical bath deposition method [74] etc.…”