Flux Crystal Growth, Crystal Structure, and Optical Properties of New Germanate Garnet Ce2CaMg2Ge3O12

摘要: A new germanate garnet compound, Ce2CaMg2Ge3O12, was synthesized via flux crystal growth. Truncated spherical, reddish-orange single crystals with a typical size of 0.1–0.3 mm were grown out BaCl2–CaCl2 melt. The characterized by single-crystal X-ray diffraction analysis, which revealed that it adopted cubic garnet-type structure = 12.5487(3) in the space group Ia–3d. Its composition is best described as A3B2C3O12, where Ce/Ca, Mg, and Ge occupied A, B, C sites, respectively. UV–vis–NIR absorption spectroscopy measurement on clear edge corresponding to band gap 2.21 eV ( 561 nm). First-principle calculations indicated valence maximum composed Ce 4f bands, whereas conduction minimum mainly consisted 5d bands. These findings explain observed through → absorption. Photoluminescence emission spectra exhibited very broad peak centered at 600 nm, transition from lowest energy d level levels.