Synthesis, phase transition and photoluminescence studies on Eu{sup 3+}-substituted double perovskites-A novel orange-red phosphor for solid-state lighting

Journal Article · Mon Dec 15 04:00:00 EST 2008 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2008.08.030· OSTI ID:21212143

Photoluminescence studies on Eu{sup 3+}-doped double perovskites with the formula A{sub 2}CaWO{sub 6} (A=Sr, Ba) revealed that the forced electric dipole (ED) transition is present when Eu{sup 3+} is substituted at the non-centrosymmetric Sr-site vis-a-vis substitution at the centrosymmetric Ca-site shows both ED and magnetic dipole (MD) transition. A series of novel orange-red-emitting phosphor compositions Sr{sub 1.9-x}Ba{sub x}Eu{sub 0.05}Li{sub 0.05}CaWO{sub 6} (x=0-1.9) have also been synthesized and characterized by powder X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS) and photoluminescence. XRD results reveal a phase transition from monoclinic to pseudo-cubic structure for x{<=}0.2. All the compositions show broad charge transfer band and orange-red (MD and ED) emission. However, the relative intensity of the MD and ED depends on the Ba content present in the host lattice. Select compositions in this system of compounds could find potential application as orange-red phosphors for white light generation using blue/near-UV GaN-based light-emitting diodes (LEDs). - Graphical abstract: A series of orange-red-emitting A{sub 2}CaWO{sub 6} (A=Sr, Ba) and Sr{sub 1.9-x}Ba{sub x}Eu{sub 0.05}Li{sub 0.05}MoO{sub 6} (x=0-1.9) phosphor with double perovskite structure have been synthesized by solid-state reaction. All the compositions show broad charge transfer band and orange-red [magnetic dipole (MD) and electric dipole (ED)] emission. The red emission of Sr{sub 1.5}Eu{sub 0.05}Li{sub 0.05}Ba{sub 0.4}CaWO{sub 6} is found to be {approx}4.5 times higher than that of commercial red phosphor (Nichia) under 465 nm excitation and hence this phosphor could be a potential candidate for white LED based on blue/NUV GaN LED.

• OSTI ID: 21212143
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 12 Vol. 181; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
BARIUM TUNGSTATES
CALCIUM TUNGSTATES
DOPED MATERIALS
ELECTRIC DIPOLES
EUROPIUM IONS
GALLIUM NITRIDES
LIGHT EMITTING DIODES
MAGNETIC DIPOLES
MONOCLINIC LATTICES
PEROVSKITE
PHASE TRANSFORMATIONS
PHOTOLUMINESCENCE
SPECTROSCOPY
STRONTIUM TUNGSTATES
SYNTHESIS
X-RAY DIFFRACTION