Devender Singh; Suman Sheoran; Vijeta Tanwar
Abstract
In this review article, different synthetic procedures and characterization techniques used for the development of materials are discussed briefly. The stability and high luminous intensity of silicate materials makes them practically important in the field of white light emitting diodes (WLEDs). During ...
Read More
In this review article, different synthetic procedures and characterization techniques used for the development of materials are discussed briefly. The stability and high luminous intensity of silicate materials makes them practically important in the field of white light emitting diodes (WLEDs). During the experimental designing of our research, we have understood carefully the theoretical and methodological strategy regarding the synthesis of phosphors and then, a large number of silicate-based luminescent materials have been prepared using sol-gel technology. Among them, a series of silicate materials having composition M(2-x)EuxSi2O7 (M = Y, Gd, La and x = 0.03 moles) have been described in this review prepared with sol-gel process. Intense peak in europium (III) doped M2Si2O7 silicates originate from 5 D0→ 7 F2 transition of Eu 3+ ion available in crystal lattices. X-ray diffraction pattern have triclinic structure for Y2Si2O7 and Gd2Si2O7 silicate phosphors. However, hexagonal and monoclinic structures are obtained for La2Si2O7 material at different temperatures employed for further annealing. Transmission electron microscopic analysis is used to study the morphology and particle size of prepared phosphors. Excellent luminescence response of these silicate phosphors make them suitable for photonic applications and also open up new avenues for solid-state lighting, cathode ray tubes, fluorescent lamps and scintillators etc.
Devender Singh; Pratap S. Kadyan;Ishwar Singh; Vijeta Tanwar; Anura P. Simantilke; Bernabe Mari
Abstract
The persistent MAl2O4:Eu 2+ , Dy 3+ (M may be Ca or Ca+Ba or Ca+Mg) blue light emitting nanophosphors were prepared by rapid facile gel combustion technique. For the syntheses of present series of phosphors, urea was used as an organic fuel and boric acid was used as a flux in presence of air. Photoluminescence ...
Read More
The persistent MAl2O4:Eu 2+ , Dy 3+ (M may be Ca or Ca+Ba or Ca+Mg) blue light emitting nanophosphors were prepared by rapid facile gel combustion technique. For the syntheses of present series of phosphors, urea was used as an organic fuel and boric acid was used as a flux in presence of air. Photoluminescence properties were studied by excitation and emission spectra. The phosphors showed blue luminescence (λmax= 454-458nm) under the excitation of UV source, attributed to 4f 6 5d 1 →4f 7 transitions of the Eu(II) ion. The effect on photoluminescence intensity and decay time was also studied for varying metal ions in different ratio (Ca or Ca+Ba or Ca+Mg). The existence of divalent europium ions in the synthesized lattices was confirmed by the X-ray photoelectron spectroscopy. The crystal phase and size of the prepared materials were analyzed with X-ray diffraction patterns. The surface morphology of phosphors was studied with scanning electron microscopy and transmission electron microscopy techniques revealed the average size of the prepared materials between the 30-50 nm. The prepared nanophosphors had bright optoelectronic properties that could be efficiently applied in various solid state white light emitting display devices.
