Rare earth (RE) doped phosphors and their emerging applications: A review

Crystal structure and photoluminescence investigations of Y3Al5O12:Dy3+ nanocrystalline phosphors for WLEDs

Abstract The photoluminescent properties of un-doped and Sm 3+ doped Ca 3 Y 2 Si 3 O 12 phosphors were prepared by the citrate sol-gel method. Un-doped sample has shown a strong blue emission, which has its maximum intensity at 389 nm. Among all the observed emission transitions 4 G 5/2 → 6 H J (J = 5/2, 7/2 & 9/2) of Sm 3+ , the reddish-orange (RO) emission transition 4 G 5/2 → 6 H 7/2 is more prominent, which matches well with the emission wavelength of near UV (n-UV) LED. The reasons for the observance of such prominent visible color emissions from these phosphors have been substantiated appropriately. Besides, structural details of these samples have also been analyzed from the measured XRD, TEM, TG-DTA and FT-IR profiles.

http://ma.ecsdl.org/content/MA2010-02/41/2316.full.pdf

Citric Sol-Gel Synthesis and Photoluminescence Properties of Un-Doped and Sm3+ Doped Ca3Y2Si3O12 Phosphors

A series of Eu(III) doped MSiO3 (M = Mg, Ca, Sr and Ba) nanomaterials of high color purity were prepared using sol–gel technique at 950 °C. Samples were further reheated at 1050 and 1150 °C for 1 h in muffle furnace to study the effect of temperature on the structural aspects and optical characteristic of prepared materials. X-ray diffraction study was used to know the crystal structure of synthesized silicate phosphors. All the prepared materials existed in the single phase and dopant ion have no influence on the crystal structure of host materials. Under 395 nm excitation, photoluminescence emission spectra of silicate materials showed the characteristic red emission in 610–615 nm region due to the electric dipole (5D0 → 7F2) transition of europium(III) ion. Color coordinate values of these materials were located in the red region of Commission Internationale de I’Eclairage triangle. Fourier transform infra red spectroscopic studies were used to know the structure and bonding present in these phosphors. Transmission electron microscopic confirmed that the particle size of prepared nanomaterials exist in the nano range. The results suggested that these red emitting phosphors could be useful for generation of white-light emitting diode applications.

Optical characteristics of Eu(III) doped MSiO 3 (M = Mg, Ca, Sr and Ba) nanomaterials for white light emitting applications

Crystal structure, photoluminescence properties and thermal stability of BaLu2Si3O10:Eu3+ red-emitting phosphors with high color purity for near-UV-excited white LEDs

Luminescence properties of europium(III) doped M3Y2Si3O12 (M = Ca, Mg, Sr and Ba) nanophosphors were characterized prepared with the sol gel technique. These materials were explored at 950 °C without adding any fuel or chelating agent and then samples were further reheated at 1050 and 1150 °C. Structural properties of resulting phosphors were analyzed with the help of X-ray diffraction study. Powder pattern of Eu3+ doped Ca3Y2Si3O12 material showed orthorhombic crystal structure having a space group of Pnma. Energy dispersive X-ray analysis was used to detect the chemical composition and presence of europium ions in the Ca3Y2Si3O12 material. Upon 395 nm excitation, these phosphors exhibited intense red color due to 4f → 4f transitions of Eu3+ ion doped in the host lattice. Among all emission transitions of europium(III) ion, 5D0 → 7F2 is the most prominent one which were centered in the region of 610–615 nm. Some weak emissive peaks were also available in the spectra due to 5D0 → 7F1 and 5D0 → 7F3 transitions of europium ion. Three mole percent concentration of europium ion was found to be optimum for doping in these fluorescent materials. The effect of temperature and concentration on luminescence characteristics of these red light emitting materials were also studied. Structure and bonding in silicate phosphors were determined using Fourier transform infra red spectroscopy. Transmission electron microscopy estimated the size of prepared materials which were found in range of 20–55 nm. High stability and excellent photoluminescence properties of these nanosized materials made them suitable for display device applications.

Synthesis and luminescent characteristics of M 3 Y 2 Si 3 O 12 :Eu 3+ (M = Ca, Mg, Sr and Ba) nanomaterials for display applications

Synthesis, luminescent and structural characteristics of Sr4Al14O25:Eu2+ and Sr4Al14O25:Eu2+, RE3+ (RE = Nd, Dy) long persistent nanophosphors for solid state lighting

Europium doped silicate phosphors: Synthetic and characterization techniques

A series of Eu3+ -doped MLaAlO4 (M = Mg2+, Ca2+, Sr2+, and Ba2+) was synthesized via self-sustained solution combustion method. The samples were prepared at 600 °C, using large range of Eu3+ ion concentration (0.01–0.05 mol) to investigate the effect of concentration of dopant on the luminescence. The optimal dopant ion concentration obtained was 0.03 mol for the prepared aluminate lattice. Upon excitation at 393 nm, the samples showed the dominant photoluminescence emission bands in red region of the spectrum. The red emission of Eu3+ -activated phosphors corresponds to 5D0 → 7F2 (forced electric dipole) transition positioned at 606–611 nm. The samples were also calcined to a higher temperature to analyze the influence of temperature on the luminous efficacy. The structural determination was done via the combined efforts of Powder X-ray diffraction (PXRD) and transmission electron microscopy (TEM) analysis. PXRD patterns of samples contain sharp peaks in 10°–80° region. Diffraction Pattern of CaLaAlO4 material has been found in close agreement to JCPDS card no. 85-1071 confirming the tetragonal crystal structure with 14/mmm space group. The crystalline nature of materials increases with rise in temperature. TEM micrographs exhibited the spherical shape of particles in 13–30 nm size. FT-IR spectra of materials showed peaks in 400–1000 cm−1 corresponding to lanthanum–oxygen and aluminum–oxygen bond vibrations. Due to excellent photoluminescent and suitable CIE coordinates, the Eu3+ -doped MLaAlO4 could have brilliant applications in the development of effective red phosphor for modern display devices and white light-emitting diodes.

Suman Sheoran

Papers

Optical characteristics of Eu(III) doped MSiO 3 (M = Mg, Ca, Sr and Ba) nanomaterials for white light emitting applications

Synthesis and luminescent characteristics of M 3 Y 2 Si 3 O 12 :Eu 3+ (M = Ca, Mg, Sr and Ba) nanomaterials for display applications

Synthesis, luminescent and structural characteristics of Sr4Al14O25:Eu2+ and Sr4Al14O25:Eu2+, RE3+ (RE = Nd, Dy) long persistent nanophosphors for solid state lighting

Europium doped silicate phosphors: Synthetic and characterization techniques

Optical and structural investigations of MLaAlO4:Eu3+ (M = Mg2 +, Ca2+, Sr2+, and Ba2+) nanophosphors for full-color displays