Due to the novel properties of both 2D materials and rare-earth elements, developing 2D rare-earth nanomaterials has a growing interest in research. To produce the most efficient rare-earth nanosheets, it is essential to find out the correlation between chemical composition, atomic structure and luminescent properties of individual sheets. In this study, 2D nanosheets exfoliated from Pr-doped KCaNbO particles with different Pr concentrations were investigated. Energy dispersive X-ray spectroscopy analysis indicates that the nanosheets contain Ca, Nb and O and a varying Pr content between 0.9 and 1.8 at%. K was completely removed after exfoliation. The crystal structure is monoclinic as in the bulk. The thinnest nanosheets are 3 nm corresponding to one triple perovskite-type layer with Nb on the B sites and Ca on the A sites, surrounded by charge compensating TBA molecules. Thicker nanosheets of 12 nm thickness (and above) were observed too by transmission electron microscopy with the same chemical composition. This indicates that several perovskite-type triple layers remain stacked similar to the bulk. Luminescent properties of individual 2D nanosheets were studied using a cathodoluminescence spectrometer revealing additional transitions in the visible region in comparison to the spectra of different bulk phases.
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http://dx.doi.org/10.1038/s41598-023-35142-3 | DOI Listing |
Symmetry-breaking spin-state transitions in two of three isostructural salts of MnIII spin-crossover cations, [MnIII(3-OMe-5-NO2-sal2323)]+, with heavy anions are reported. The ReO4- salt undergoes two-step spin crossover which is coupled with a re-entrant symmetry-breaking structural phase transition between a high temperature phase (S = 2, C2/c), an intermediate ordered phase (S = 1/S = 2, P21/c), and a low temperature phase (S = 1, C2/c). The AsF6- complex undergoes an abrupt transition between a high temperature phase (S = 2, C2/c) and a low temperature ordered phase (S = 1/S = 2, P-1).
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View Article and Find Full Text PDFEnviron Sci Technol
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State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
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Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
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View Article and Find Full Text PDFJ Am Chem Soc
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Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States.
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