Synthesis, thermal and spectroscopic characterization of Caq2 (calcium 8-hydroxyquinoline) organic phosphor.

Bluish-green photoluminescence from calcium 8-hydroxyquinolate (Caq(2)) powder, synthesized by a co-precipitation route, and a blended Caq(2):PMMA thin film is reported. The film was obtained by mixing the Caq(2) powder with PMMA (Polymethylmethacrylate) in a chloroform solution. X-ray diffraction analyses confirm the formation of the Caq(2) powder and thin film. Further structural elucidation was carried out using Fourier transform infrared spectroscopy (FTIR) in which the stretching frequencies of the Caq(2) bonds were determined. Bluish-green photoluminescence with a maximum at 480 nm was observed from the powder and the emission was red-shift by 10 nm in the case of the thin film. The UV-vis absorption bands were split and shifted due to different orientations of the Caq(2) molecules in both the powder and thin film. It was confirmed by thermogravimetric (TGA) and differential thermal analysis (DTA) that the Caq(2) powder was stable up to ≈ 380 °C. Atomic force microscopy images showed the continuous distribution of the Caq(2) atoms in the PMMA thin film. X-ray photoelectron spectroscopy data was used to estimate the binding energies of the chemical bonding in the Caq(2) powder complex. The optical properties of the Caq(2) powder and thin film were evaluated for possible applicable in organic light emitting devices.

Effect of temperature on intense green emitting Na2Ca(PO4)F:Mn²âº phosphor.

An intense green luminescent Na2Ca(PO4)F:Mn²âº phosphor has been prepared at high temperature by reduction treatment in a charcoal environment. The emission band of Mn²âº was obtained at around 522 nm (green) under 259 nm excitation. Enhancement in emission intensity arising from the thermal treatment is reported. The intense emission of the spectrum was assigned to electronic transitions 4T1 → 6A1 of Mn²âº ions. Intense PL emission suggested that temperature employed plays an important role in the present matrix. X-ray diffraction pattern, photoluminescence and morphology by SEM of the host lattice of phosphors at different temperatures have been reported in this paper. The results obtained show that the present phosphor has potential for application in green emitting phosphors for the lamp industry.

Combustion synthesis of Na2Sr(PO4)F:Dy3+ white light emitting phosphor.

The synthesis, X-ray diffraction, photoluminescence, TGA/DTA and FTIR techniques in Dy(3+) activated Na(2)Sr(PO(4))F phosphor are reported in this paper. The prepared phosphor gave blue, yellow and red emission in the visible region of the spectrum at 348 nm excitation. CIE color co-ordinates of Na(2)Sr(PO(4))F:Dy(3+) are suitable as white light-emitting phosphors.

Eu3+ (orange/red) luminescence in LiXSO4Cl (X = Mg, Zn) halosulfate phosphor.

The wet chemical synthesis, X-ray diffraction and photoluminescence characteristics in alkaline halosulfate phosphors such as LiMgSO4Cl:Eu and LiZnSO4Cl:Eu are reported in this paper. The effect of Li ion on Eu3+ luminescence (5D(0) --> 7F(2) electronic transition) and incorporation of Eu3+ ion in lithium base alkaline halosulfate phosphor has been studied.