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We investigated high-pressure induced phase transitions in Y 2 O 3 and Eu-doped Y 2 O 3 ͑Y 2 O:Eu 3+ ͒ using angular dispersive synchrotron x-ray diffraction, Raman spectroscopy, and photoluminescence ͑PL͒. With increasing pressure, we observed a series of phase transformations in Y 2 O 3 :Eu 3+ , which followed a structure sequence of cubic→ monoclinic→ hexagonal, while Y 2 O 3 followed a sequence of cubic→ hexagonal. During decompression, both hexagonal structured Y 2 O 3 and Y 2 O 3 :Eu 3+ transformed into monoclinic phases which were quenchable back to ambient pressure. Raman and PL measurements shed additional light on the different phase transition behavior in these two samples.

Red phosphors BaTiF6:Mn(4+) with microrod and polyhedron morphologies have been prepared respectively by etching TiO2 and Ti(OC4H9)4 in a HF solution with an optimized concentration of KMnO4 at 1.5 mmol L(-1) in hydrothermal conditions. The red phosphor BaTiF6:Mn(4+) exhibits a broad excitation band in the blue region and sharp emission peaks in the red region. A white LED (WLED) fabricated with the red phosphor BaTiF6:Mn(4+) shows "warm" white light that possesses a color rendering index of 93.13 at a color temperature of 4073.1 K.