Flux-Assisted Boron Chalcogen Mixture (BCM) Method for Synthesizing Mixed Chalcogenide Semiconductors (AkRE2 Si2 SexS8–x and CaRE2 Si2 Se8) ( Ak = Ca and Sr; RE = La, Ce, Pr, Nd, and Sm): Investigation of Their Magnetic and Optical Properties
Document Type
Article
Abstract
We report a detailed structural analysis of a series of ten quaternary rare earth-containing seleno-thiosilicates AkRE2Si2SexS8–xand selenosilicates, CaRE2Si2Se8(Ak = Ca and Sr; RE = La, Ce, Pr, Nd, and Sm). Single crystals were obtained by using the flux-assisted boron chalcogen mixture (BCM) method, and single-crystal X-ray diffraction was used to determine their structures. All members of the AkRE2Si2SexS8–xand CaRE2Si2Se8series crystallize in the space group R3̅c (space group number 167) of the trigonal crystal system. The single-crystal X-ray diffraction analysis revealed a strong preference for Se/S atoms to occupy one vs the other of the two available sites. Polycrystalline samples were used for the magnetic susceptibility and UV–visible diffuse reflectance measurements. Magnetic measurements show that CaCe2Si2Se1.73S6.27and CaNd2Si2Se2.5S5.5are paramagnetic with negative Weiss constants (θ = −60.1 and −26.2). Diffuse reflectance analysis gives optical band gaps of 2.7(1) eV (CaLa2Si2Se2.38S5.62), 2.2(1) eV (CaCe2Si2Se1.73S6.27), 2.5(1) eV (CaNd2Si2Se2.5S5.5), and 2.0(1) eV (CaCe2Si2Se8), consistent with density functional theory calculations. By partially or fully replacing S sites with Se, it was possible to achieve band gap tuning. Photoluminescence behavior was also investigated for CaCe2Si2Se1.73S6.27via irradiation with 375 nm ultraviolet light.
Digital Object Identifier (DOI)
Publication Info
Published in Inorganic Chemistry, Volume 64, Issue 45, 2025, pages 22402-22411.
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© 2025 American Chemical Society
APA Citation
Kumar, & Morrison (2025). Flux-Assisted Boron Chalcogen Mixture (Bcm) Method for Synthesizing Mixed Chalcogenide Semiconductors (Akre2Si2Sexs8–Xand Care2Si2Se8) (Ak = Ca and Sr; Re = La, Ce, Pr, Nd, and Sm): Investigation of Their Magnetic and Optical Properties. Inorganic Chemistry, 64(45), 22402–22411. https://doi.org/10.1021/acs.inorgchem.5c03737