Mechanochemical Synthesis of Sustainable Ternary and Quaternary Nanostructured Cu2SnS3, Cu2ZnSnS4, and Cu2ZnSnSe4 Chalcogenides for Thermoelectric Applications

Abstract

Copper-based chalcogenides have emerged as promising thermoelectric materials due to their high thermoelectric performance, tunable transport properties, earth abundance and low toxicity. We have presented an overview of experimental results and first-principal calculations investigating the thermoelectric properties of various polymorphs of Cu2SnS3 (CTS), Cu2ZnSnS4 (CZTS), and Cu2ZnSnSe4 (CZTSe) synthesized by high-energy reactive mechanical alloying (ball milling). Of particular interest are the disordered polymorphs of these materials, which exhibit phonon-glass–electron-crystal behavior—a decoupling of electron and phonon transport properties. The interplay of cationic disorder and nanostructuring leads to ultra-low thermal conductivities while enhancing electronic transport. These beneficial transport properties are the consequence of a plethora of features, including trap states, anharmonicity, rattling, and conductive surface states, both topologically trivial and non-trivial. Based on experimental results and computational methods, this report aims to elucidate the details of the electronic and lattice transport properties, thereby confirming that the higher thermoelectric (TE) performance of disordered polymorphs is essentially due to their complex crystallographic structures. In addition, we have presented synchrotron X-ray diffraction (SR-XRD) measurements and ab initio molecular dynamics (AIMD) simulations of the root-mean-square displacement (RMSD) in these materials, confirming anharmonicity and bond inhomogeneity for disordered polymorphs.

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

“…Calculated lattice parameters a = b = c = 5.51 Å and the unit cell volume of 161.8 Å 3 from the refinement model also match closely to the standard (ICSD-43532) reported data for cubic CTS . Furthermore, we have calculated the crystallite size by considering the microstrain effect and Debye–Waller coefficient (applying pseudo-Voigt profile function), , using Sherrer’s equation, which is about 29 nm. The PXRD pattern of the pressed Bi film on emery paper is shown in Figure d, which matches with the standard JCPDS data (Card no.…”

Optimizing CuFeS2 Chalcopyrite Thin Film Synthesis: A Comprehensive Three-Step Approach Using Ball-Milling, Thermal Evaporation, and Sulfurization Applied for Thermoelectric Generation

“…In this study, we present a comprehensive analysis of the three-step synthesis of CFS, examining its physical and chemical properties. Moreover, we demonstrate its successful application as a thermoelectric generator, yielding a power output comparable to similar chalcogenide-based materials [20,[46][47][48][49][50]. Comparing our proposed three-step method with existing literature can offer valuable insights into the potential applications of CFS chalcopyrite beyond thermoelectricity.…”

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

“…The external cation doping at the Sn site transforms the monoclinic polymorph into cubic ( F 4̅3 m ). It is worth mentioning that partially (SG: I 4̅2 m ) or fully (SG: F 4̅3 m ) disordered CTS polymorphs can also be obtained by synthesis methods, e.g., colloidal method and high-energy reactive ball milling. , Recently, Koskela et al reported an orthorhombic ( Cmc 2 1 ) CTS polymorph. Polymorphism in these materials offers multiple possibilities of structural manipulation and band engineering to boost the TE performance.…”