Abstract
The MAl12O19:Eu (M = Ca, Ba, Sr) phosphor were synthesized by combustion method and systematically characterized by photoluminescence excitation and emission spectra, concentration quenching, morphology and X-ray mapping with scanning electron microscopy. In SrAl12O19:Eu phosphor two PL emission peaks are observed at about 389 nm and another around 420 nm as well as BaAl12O19:Eu phosphor shows blue emission around 460 nm is observed in the blue region of the spectrum and CaAl12O19:Eu shows only red emission at 592 as well as 615nm. Both phosphors can be efficiently excited in the wavelength range of 250-425 nm, where the near UV (~320 nm) solid state excitation is matched. By combining MAl12O19:Eu (M = Ca, Ba, Sr) phosphor with near UV chops emitting intense blue green (Ba), yellow-red (Ca) and blue purple (Sr) LEDs white LEDs can be produced. Copyright © 2011 VBRI press.
Highlights
Rare-earth and non-rare-earth-doped inorganic phosphors are widely used in a variety of applications, such as lamp industry, radiation dosimetry, X-ray imaging, and colour display
The photoluminescence emission spectra for the M1-xAl12O19: Eux (M = Sr, Ba, Ca) phosphors by 320 nm excitation shown in Fig. 2 a-c
The PL emission in Ca1−xEuxAl12O19 phosphor observed at 592 and 615 nm sharp peaks in the red region of the spectrum due to 5D0 → 2F0 and 5D0 → 2F1 transition of Eu3+ ion, in this phosphor Eu3+ ion may be enter in side symmetry of lattice of the host material during preparation of phosphor as well changing matrix crystal structure and formation of aggregation of nanopartilces, Eu ion observed in the Eu3+ valance state
Summary
Rare-earth and non-rare-earth-doped inorganic phosphors are widely used in a variety of applications, such as lamp industry, radiation dosimetry, X-ray imaging, and colour display. The luminescent properties of europium-ion doped phosphors have been studied extensively for their applications in these areas [1, 2]. Eu2+ activated phosphors MAl2O4 and MAl12O19 (M = Sr, Ba, Ca, Mg) are well known since the studies by Blasse and Brill [3] in the 1960s. Their researches lead to the conclusion that these compounds were adequate phosphorescent materials because of their high quantum efficiency in the visible region. A completely new generation of persistent luminescent phosphors, Eu2+ doped alkaline earth aluminates, MAl2O4:Eu2+ (M = Ca, Sr), has been developed to replace ZnS:Cu [4].
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