Enhanced Thermoelectric Performance of Tin(II) Sulfide Thin Films Prepared by Aerosol Assisted Chemical Vapor Deposition

Abstract

Orthorhombic SnS exhibits excellent thermoelectric performance as a consequence its relatively high Seebeck coefficient and low thermal conductivity. In the present work, polycrystalline orthorhombic SnS thin films were prepared by aerosol-assisted chemical vapor deposition (AACVD) using the single source precursor dibutyl-bis(diethyldithiocarbamato)­tin­(IV) [Sn­(C4H9)2(S2CN­(C2H5)2)2]. We examined the effects of the processing parameters on the composition, microstructure, and electrical transport properties of the SnS films. Deposition temperature dominates charge transport; the room temperature electrical conductivity increased from 0.003 to 0.19 S·cm–1 as deposition temperature increased from 375 to 445 °C. Similarly, the maximum power factor (PF) increased with deposition temperature, reaching ∼0.22 μW·cm–1·K–2 at 570 K. The power factors for SnS films deposited by AACVD are higher than values from earlier work on SnS bulks and SnS/SnSe films at temperatures up to 520 K. The electronic structure and electrical transport properties of SnS were investigated using density-functional theory to provide an improved understanding of the materials performance. To the best of our knowledge, the thermal conductivity (κ) of SnS film was measured for the first time allowing the figure of merit (zT) for SnS film to be evaluated. A relatively low thermal conductivity of ∼0.41 W·m–1·K–1 was obtained at 550 K for SnS films deposited at 445 °C; the corresponding zT value was ∼0.026. The SnS films are good candidates for thermoelectric applications and AACVD is a promising technique for the preparation of high-performance thermoelectric films.

Exceptional Thermoelectric Performance of Cu2(Zn,Fe,Cd)SnS4 Thin Films

“…Samples with a Cu/(Zn + Sn) ratio of 1.01 had the highest PF of 46.52 μW K −2 m −1 at 400 K. 18 As a processing technique, aerosol-assisted chemical vapor deposition (AACVD) has the advantages of being low cost and simple to operate, together with easily adjustable atomic ratios compared to many established CVD-type processes. 19 In this work we employ AACVD to deposit CZTS thin films using metal diethyldithocarbamate complexes as precursors. 20 In an earlier investigation, Kevin et al prepared Cu 2 (Zn y Fe 1−y )SnS 4 (CZFTS) and Cu 2 (Zn y Fe 1−y )SnSe 4 (CZFTSe) thin films using AACVD, and their Fe-rich CZFTS thin films, deposited with 1:1 molar ratio of Fe and Zn diethyldithocarbamate precursors, showed significantly enhanced electrical conductivity.…”

Thermoelectric properties of Pnma and R3m GeS and GeSe

“…31–36 SnSe has been identified as an extremely promising TE material with an ultra-high bulk ZT max ≈ 2.6 at 923 K, 37 a good ZT over a wide temperature range of 300–773 K, 38 and an even higher polycrystalline ZT max ≈ 3.1 at 773 K. 39 SnS shows very similar structural chemistry to SnSe, and is advantageous due to the higher abundance and lower toxicity of S, but has yet to demonstrate comparable TE performance. 40–42…”

“…[31][32][33][34][35][36] SnSe has been identified as an extremely promising TE material with an ultra-high bulk ZT max E 2.6 at 923 K, 37 a good ZT over a wide temperature range of 300-773 K, 38 and an even higher polycrystalline ZT max E 3.1 at 773 K. 39 SnS shows very similar structural chemistry to SnSe, and is advantageous due to the higher abundance and lower toxicity of S, but has yet to demonstrate comparable TE performance. [40][41][42] The Ge chalcogenides exhibit similar structures and optoelectronic properties to the Sn analogues, but their TE performance is less well characterised. However, Ge is 1000Â more abundant than Te and less toxic than Pb, 43 making GeS and GeSe attractive as prospective TEs.…”

Thermoelectric Performance of Tetrahedrite (Cu12Sb4S13) Thin Films: The Influence of the Substrate and Interlayer

“…Thin-film thermoelectric materials offer numerous advantages, including low costs, low weights, and niche deployment opportunities. These qualities mean that thin-film materials are particularly well-suited for the development of compact devices, such as wearable electronics and microscale cooling systems, in contrast to the challenges bulk materials face in small-scale applications . In view of the excellent thermoelectric performance of Cu 12 Sb 4 S 13 bulk materials, there should be opportunities for Cu 12 Sb 4 S 13 thin films to be used in portable and wearable thermoelectric devices.…”