In order to explore a new family of phosphate phosphors, the synthesis and crystal structure of a novel phosphate family, Ca 19 M 2 (PO 4 ) 14 (M ¼ Mg, Zn, Mn), were investigated. Eu 3+ doped Ca 19 Mg 2 (PO 4 ) 14 red phosphor was also successfully synthesized with the objective of application in ultraviolet-based lightemitting diodes (LEDs) and field emission displays (FEDs). The characteristic photoluminescence properties were studied in detail by photoluminescence excitation (PLE), emission (PL) spectra and decay times. The Ca 19 Mg 2 (PO 4 ) 14 :0.06Eu 3+ phosphor offers higher brightness and thermal stability than the commercial Y 2 O 3 :Eu 3+ . The unexpected temperature-dependent luminescence from higher 5 D 1 states was observed and was explained via the configuration coordinate diagram. The cathodoluminescence (CL) spectra as a function of accelerating voltage and probe current were also measured. Excellent degradation properties with good color stability were obtained by continuous low-voltage electronbeam excitation of the phosphor. The results indicate that the phosphor Ca 19 Mg 2 (PO 4 ) 14 :0.06Eu 3+ can be a suitable red-emitting phosphor candidate for LEDs and FEDs.

Graphene sheets were obtained through solvothermal reduction of colloidal dispersion of graphene oxide in benzyl alcohol. The graphene/rod-shaped TiO(2) nanocomposite was synthesized by this novel and facile solvothermal method. During the solvothermal reaction, both the reduction of graphene oxide and the growth of rod-shaped TiO(2) nanocrystals as well as its deposition on graphene occur simultaneously. The photocatalytic activity of graphene/rod-shaped TiO(2) and graphene/spherical TiO(2) nanocomposites was compared. In the photocatalytic degradation of methyl orange (MO), the graphene/rod-shaped TiO(2) nanocomposite with the optimized graphene content of 0.48 wt% shows good stability and exhibits a significant enhancement of photocatalytic activity compared to the bare commercial TiO(2) (P25) and graphene/spherical TiO(2) nanocomposite with the same graphene content. Photocurrent experiments were performed, which demonstrate that the photocurrent of the graphene/rod-shaped TiO(2) nanocomposite electrode is about 1.2 times as high as that of the graphene/spherical TiO(2) nanocomposite electrode. The photocatalytic mechanism of graphene/rod-shaped TiO(2) nanocomposite was also discussed on the basis of the experimental results. This work is anticipated to open a possibility in the integration of graphene and TiO(2) with various morphologies for obtaining high-performance photocatalysts in addressing environmental protection issues.

A series of composites of nanocrystalline TiO 2 with exposed {001} facets and high quality graphene sheets (GS) were synthesized via a one-step hydrothermal reaction in an ethanol-water solvent. The obtained {001} facets-exposed TiO 2 /GS photocatalysts were characterized by Raman spectroscopy (RS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction pattern (XRD), field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet visible (UV-vis) diffuse reflectance spectroscopy (DRS) and Electrical Impedance Spectroscopy (EIS). They showed a better photocatalyst properties than P25 and other normal TiO 2 /GS composites, which could be explained on the basis of the formation of chemical Ti-O-C bond and the formation of nano-sized Schottky interfaces at the contacts between TiO 2 and GS. The influence of the exposed {001} facets on the photocatalytic activity was investigated. The result showed that positively charged dye molecules are preferentially adsorbed onto the TiO 2 /GS composites due to the photogenerated charge gathered on GS. Overall, this work could provide new insights into the fabrication of TiO 2 -carbon composites as high performance photocatalysts and facilitate their application in addressing environmental protection issues.

A novel red-emitting oxonitridosilicate phosphors, Sr 2 SiN z O 4À1.5z :Eu 2+ (0.7 < z < 1.2), was prepared by solid state reaction in NH 3 -N 2 atmosphere. The crystal structure was determined by Rietveld analysis on powder X-ray data. Sr 2 SiN z O 4À1.5z (0.7 < z < 1.2) crystallizes in an orthorhombic structure with the space group of Pmnb: baÀc (no. 62), and cell parameter a ¼ 5.67366(5) Å, b ¼ 7.09777(4) Å, c ¼ 9.75112(1) Å.Sr 2 SiN z O 4À1.5z :Eu 2+ (0.7 < z < 1.2) exhibited broad-band red emission centred at $620 nm (FWHM z 95 nm) under blue light irradiation with a high QE value of 78.0% and good thermal stability, its emission intensity remains 87% at 150 C of that measured at room temperature. The outstanding luminescent properties allow it to be an attractive red luminescent material for white LEDs.

Y₃Al₅O₁₂:0.06Ce³⁺, xMn²⁺ (YAG:0.06Ce,xMn) phosphors have been synthesized and the effect of different charge compensators on the color adjustment has been investigated for the first time. The luminescence properties of Mn2+ singly doped and co-doped with Ce3+ into YAG host have been discussed. It is observed that in singly doped sample, Mn2+ ions not only occupy two kinds of Al3+ sites to generate a yellow and a deep red emission bands, but also occupy Y3+ sites to obtain a green emission band in YAG host. Considering Mn2+ substitution for Al3+, quadrivalence ions including Zr4+, Ge4+ and Si4+ ions are introduced to balance the charge difference. The results show that Si4+ as charge compensator exhibits the best tunable effect on controlling the Mn2+ emissions in YAG:0.06Ce, xMn. In Si4+-Mn2+ co-doped samples, the emission color can be tuned from greenish-yellow to red with increasing the content of Mn2+. The Commission International de L’Eclairage (CIE) chromaticity coordinates are also investigated.