A novel green-emitting phosphor Ca 2 Al 3 O 6 F:Eu 2+ was synthesized and its photoluminescence (PL) properties were investigated for application in white light-emitting diodes (w-LEDs). This phosphor shows good absorption ranging from the ultraviolet to the blue region and a broad green emission band centered at 502 nm. The concentration quenching mechanism and fluorescence lifetime of Eu 2+ emission in the Ca 2 Al 3 O 6 F:Eu 2+ phosphors have been investigated. The key parameters for the fabrication of w-LED lamps, such as the temperature-dependent photoluminescence, microstructure and morphology, CIE value and quantum efficiency of Ca 2 Al 3 O 6 F:Eu 2+ phosphors, have also been studied. The above results indicate that Ca 2 Al 3 O 6 F:Eu 2+ is a good candidate as a green component for near UV-excited w-LEDs.

Ammonia borane, NH(3)BH(3), has attracted significant interest as a promising candidate material for hydrogen storage. The effect of pressure on the bonding in NH(3)BH(3) was investigated using Raman spectroscopy to over 20 GPa in a diamond anvil cell, and two new transitions were observed at approximately 5 and 12 GPa. Vibrational frequencies for the modes of the NH(3) proton donor group exhibited negative pressure dependence, which is consistent with the behavior of conventional hydrogen bonds, while the vibrational frequencies of the BH(3) proton acceptor group showed positive pressure dependence. The observed behavior of these stretching modes supports the presence of dihydrogen bonding at high pressure. In addition, the BH(3) and NH(3) bending modes showed an increase in spectral complexity with increasing pressure together with a discontinuity in d nu/d P which suggests rotational disorder in this molecule. These results may provide guidance for understanding and developing improved hydrogen storage materials.

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Nanocrystalline LiFePO 4 and doped LiTi 0.01 Fe 0.99 PO 4 powders were synthesized via a sol-gel preparation route. High-resolution tunneling electron microscopy observation and energy dispersive spectroscopy, mapping show the homogeneous distribution of dopant Ti cations in the crystals. Fe and O K-edge X-ray absorption near-edge structure ͑XANES͒ measurements show that Ti 4+ doping induces an increased unoccupied d-state in LiFePO 4 , resulting in an enhanced p-type semiconductivity. In situ Fe K-edge XANES measurements of Ti-doped and undoped LiFePO 4 electrodes have been performed to determine the change of Fe valence during the lithium intercalation and de-intercalation processes. Both LiFePO 4 and doped LiTi 0.01 Fe 0.99 PO 4 cathodes demonstrate good electrochemical performance.