A new single-phased white light-emitting phosphor, Y 2 WO 6 :Sm 3+ , was synthesized via conventional solidstate reaction calcining in air. The Y 2 WO 6 :Sm 3+ samples were characterized using powder X-ray diffraction and refined with Rietveld methods. The phosphors exhibit a green emission from the host as well as a red emission from the dopant under ultraviolet excitation (300-380 nm). The color coordinates can be gradually tuned from green (0.247, 0.380) through white-light (0.319, 0.382) toward orange (0.335, 0.390) in the visible spectral region by systematically changing the Sm 3+ dopant concentration. In addition, combining a 365 nm near-ultraviolet chip and Y 2 WO 6 :0.02Sm 3+ phosphor produced a white light-emitting diode, which exhibited an excellent color rendering index (Ra) of 92.3, a correlated color temperature of 5916 K and CIE coordinates of x = 0.3246, y = 0.3242.

A series of single-phase yttrium tungstate powders were synthesized through solid-state reaction under air or argon atmosphere. All powders showed broad band emission in the visible light region, and the argon-calcined samples presented strong near-infrared luminescence. Moreover, the long-wave excitation bands peaking at 340, 378, 380, 490, and 523 nm depended critically on the calcination atmosphere and temperature. The emergence of these new excitation bands was ascribed to different oxygen vacancy concentrations with the analysis of the first-principle calculation, Raman and X-ray absorption fine structure spectra. The oxygen vacancies caused the reduction of the average coordination number of tungsten, and the position of the localized energy band changed with the oxygen vacancy concentration. Finally, a schematic photoluminescence excitation model was proposed via anion and cation charge transfer. The obtained results promise to be very useful in interpreting self-activated tungstate luminescence mechanism. They can also serve as guide line for tuning the luminescence performance of yttrium tungstate and related materials.

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Copper phthalocyanines (CuPc) on a Ag(110) surface have been studied by ultraviolet photoemission spectroscopy (UPS). On depositing CuPc organic films, the features from the substrate 3d valence fade and four new features corresponding to the adsorbed molecules emerge at 1.68, 4.45, 6.36 and 9.20 eV below the Fermi level. These features shift in binding energy with increasing thickness of the organic films. In the case of a monolayer, angle-resolved UPS measurements suggest that the molecular plane is nearly parallel to the substrate. Further theoretical calculation indicates that the adsorption of CuPc on a hollow site is the most favourable configuration, and the separation between the adsorbate and the substrate is about 2.7 Å.