K. Rajamohan Reddy

Fluorescence spectra of Eu3+:Ln2O2S (Ln = Y, La, Gd) powder phosphors

This paper reports the preparation and analysis of the photoluminescence spectra of Eu3+-doped lanthanide oxysulfide [Y2O2S, La2O2S, and Gd2O2 S]powder phosphors. These phosphors have displayed bright red color under a UV source. The richness of the red color has been verified by determining their color coordinates (X, Ȳ) from the CIE standard charts, and this red emission has been assigned to the transition [5D0 → 7F2]at 625 nm. Besides this stronger emission transition, four weaker fluorescent transitions have been observed, and for these the relative fluorescence intensity ratios (R) have been determined.

Fluorescence spectra of Sm3+-doped lanthanide oxychloride powder phosphors

Abstract The fluorescence properties of Sm 3+ -doped LaOCl, GdOCl, YOCl, (La, Gd)OCl, (La, Y)OCl and (Gd, Y)OCl powder phosphors are reported. The measured photoluminescence spectra have been analysed by determining their colour coordinates ( X , Y ), the relative fluorescence intensity ratios ( red orange ) and their stimulated emission cross sections ( σ P E ). These Sm 3+ -phosphors have displayed bright reddish-orange colour due to the transitions 4 G 5 2 → 6 H 9 2 (red) and 4 G 5 2 → 6 H 7 2 (orange) under a UV source (150 W xenon arc lamp). The LaOCl phosphor could be suggested as a promising material for the reddish-orange colour emission for its use on the screens of optical electronic systems.

Photoluminescence spectra of LaOBr:Eu3+ powder phosphors

This paper repons the fluorescence spectra of powder phosphors of LaOBr:Eu3+ (in six concentrations). These phosphors are brightly fluorescent with a reddish-orange colour under a UV source and they are assigned to a transition (5D0 → 7F2) at 615 nm. Colour richness has been assessed by computing the colour coordinates [X, Y] by means of the CIE chromaticity diagram. The relative fluorescence intensity ratios (R) for the different fluorescent bands measured have also been determined.

Fluorescence Spectra of Eu3+ and Tb3+ Doped Na6 Ln (BO3)3 (Ln = La, Gd, Y) Phosphors

Abstract The fluorescence properties of Eu3 + and Tb3+ doped Na6La(BO3)3, Na6Gd(BO3)3, Na6Y(BO3)3, Na6(Gd, Y) (BO3)3 powder phosphors are reported. These phosphors display fluorescent RED and GREEN colours when droped with Eu3+ and Tb3+ ions, respectively. The best fluorescence performance was consistantly observed from the Na-Gd based hosts. The photoluminescence spectra were analysed by evaluating colour coordinates, relative intensity ratios, and stimulated emission cross-sections.

Fluorescence spectra of BaFCl: Eu2+ powder phosphors

Abstract The preparation and the dopant ion concentration effects on the relative fluorescence intensity of the photoluminescence spectra of BaFCl: Eu2+ powder phosphors are described. These phosphors show a well-defined emission transition ( 4f 6 ( 7 F J )5d → 4f 7 ( 8 S 7 2 )) at 380 nm when excited with a UV source (280 nm). The measured XRD spectra have confirmed the formation of BaFCl crystal structure with tetragonal space group.

Fluorescence Spectra of Tb3+: Ln2O2S Powder Phosphors

Abstract The photoluminescence spectra of Tb3+ doped lanthanide oxysulfides (Y2O2S, La2O2S and Gd2O2S) powder phosphors are reported. These phosphors display bright fluorescent green under a UV source. The colour emission richness has been understood by computing the colour co-ordinates ([Xbar],[Ybar]). From their recorded photoluminescence spectra, the relative fluorescence intensity ratios have also been determined to examine the host material effects.

Spectral properties of Eu3+: B2O3-P2O5-R2SO4 glasses

Abstract This paper reports the synthesis of three europium glasses in the composition 44.5B 2 O 3 + 44.5P 2 O 5 + 10R 2 SO 4 (where R = Li, Na and K). For these optical glasses, physical and non-linearity property parameters have been computed from their densities and refractive indices at three different wavelengths (656.3, 589.3 and 486.1 nm), respectively. On excitation with 395 nm (Xe-Arc lamp radiation) these Eu 3+ glasses were found to be red fluorescent and the richness of the red colour was high in the Li + -glass compared to the Na + and K + glass systems. The radiative properties of the fluorescent transitions of the Eu 3+ -glasses can be understood by correlating the measured photoluminescence spectra with the Judd-Ofelt intensity factors obtained from the recorded absorption spectra.

Photoluminescence spectra of CaFCl:Eu2+ powder phosphors

This short communication summarises the effects of the dopant ion concentration on the photoluminescence efficiency of CaFCl: Eu2+ powder phosphors. These phosphors have displayed a fluorescent transition (4f6(7FJ)5d → 4f7(8S72)) at 395 nm upon excitation by a UV source (280 nm). Measured XRD spectra confirm the presence of Eu2+ in all six synthesized powder phosphors.

Fluorescence spectral properties of Sm3+- and Dy3+-doped laser liquids

Abstract This brief note reports the fluorescence characteristics of the measured emission transitions of Sm 3+ - and Dy 3+ -doped (SeOCl 2 + SnCl 4 ) laser liquids, by the application of the Judd-Ofelt intensity factors obtained from their absorption spectral profiles.

Photoluminescence spectra of BaFCl: Eu2+ phosphors

Abstract The fluorescence spectra of BaFCl: Eu 2+ powder phosphors prepared both in neutral and carbon atmospheres are reported. Upon the UV lamp excitation, these two phosphor materials have shown brighter fluorescence at λ em = 380 nm and 384 nm respectively.