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Abstract: Bi2S3 microcrystallites with three-dimensional (3D) superstructures were synthesized by the reaction of bismuth nitrate (Bi(NO3)3) with sodium O-isopropyldithiocarbonate (isopropyl xanthate, C3H7OCS2Na) at 80°C in N,N-dimethylformamide (DMF) solution without any surfactants. It was observed that Bi2S3 crystalline nanorods aggregated to urchin-like globules in the microscale when C3H7OCS2Na was slowly added to Bi(NO3)3 in DMF solution at 80°C, while cockscomb-like microspheres aggregated by Bi2S3 nanobelts with a typical width of ∼20nm were obtained if two precursors were mixed at room temperature and then heated to 80°C. Possible mechanisms for the formation of 3D Bi2S3 microcrystals were proposed. The structures of Bi2S3 crystals were examined by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and laser Raman spectroscopy. [Copyright &y& Elsevier]

The rare-earth chalcogenide Er 2 Te 3 exhibits substantial promise as an innovative thermoelectric material. However, there have been limited studies exploring its thermoelectric properties in depth. Our study employed a first-principles approach in conjunction with the semi-classical Boltzmann transport theory to investigate the collaborative modulation of the thermoelectric transport properties of Er 2 Te 3 through the concurrent application of sulfur-group elements doping and strain engineering. The findings demonstrate that, in the presence of the synergistic interplay of doping and strain, the maximum power factor (PF) of p-type Er 2 Te 3 at 300 K increases to approximately 1.8 mW·m−1·K−2, while n-type Er 2 Te 3 is elevated to approximately 18 mW·m−1·K−2. Furthermore, the cooperative effects of doping and strain augmentation raise the optimal thermoelectric figure of merit (ZT) of p-type Er 2 Te 3 material to 0.3 at 300 K and n-type Er 2 Te 3 material to 1.35 when subjecting the n-type Er 2 Te 2.82 Po 0.18 system to a −2% strain. These results suggest that even minor doping can yield similar enhancements in the thermoelectric performance of Er 2 Te 3 , particularly under conditions of smaller strain. Consequently, our work underscores the significance of synergistic interactions between doping and strain engineering as potent means to augment the thermoelectric performance of Er 2 Te 3 materials. In light of the practical feasibility of the fabrication techniques employed, this novel rare-earth chalcogenide material warrants further scrutiny and subsequent exploration within experimental domains. [Display omitted] • The effectiveness of combining doping and strain to improve the thermoelectric performance of Er 2 Te 3. • This innovative rare-earth chalcogenide material Er 2 Te 3 is a promising thermoelectric material. • It as a promising contender for room-temperature thermoelectric applications. [ABSTRACT FROM AUTHOR]

Cu 2 ZnSn(S,Se) 4 nanocrystals up to 10 grams per batch were acquired by a large-scale hydrothermal synthetic method. The bandgap engineering of Cu 2 ZnSn(S,Se) 4 nanocrystals was achieved by controlling the ratios of sulfur and selenium atoms in the solid solution nanocrystals. The bandgaps of Cu 2 ZnSn(S,Se) 4 nanocrystals were tuned approximately linearly from 1.29, 1.34, 1.39, 1.44 to 1.52 eV with the increase of sulfur and selenium atomic ratios. Finally, the thermoelectric properties of Cu 2 ZnSn(S,Se) 4 nanocrystals with the various ratios of Se/(S+Se) (0, 0.25, 0.5, 0.75, 1) from 300 to 700 K are elaborated in detail, indicating that the thermal conductivity of Cu 2 ZnSn(S,Se) 4 nanocrystals is lower than that of their bulk counterparts and other binary materials. Besides, the Seebeck coefficients and figure of merit for Cu 2 ZnSn(S,Se) 4 nanocrystals (x = 0.25, 0.5, 0.75) is higher than those of Cu 2 ZnSnS 4 and Cu 2 ZnSnSe 4 nanocrystals. It is indicated that transferring from bulk materials to the solid solution nanomaterials is an effective way to further enhance the TE performance of CZTS NCs. [ABSTRACT FROM AUTHOR]