VUV investigation of blue emitting MAl12O19: Eu (M = Ca, Sr, Ba) phosphors synthesized by combustion method

Abstract

Synthesis of europium doped alkaline earth aluminates MAl12O19 [M=Ca, Sr, Ba] by low temperatures (500ºC) solution combustion method. It corresponds to maintain the ratio of metal nitrate and urea solution mixtures. The characterization of Eu doped MAl12O19 [M=Ca, Sr, Ba] materials were done by X-ray diffraction, scanning electron microscope analysis and the optical properties were studied under 147 nm and 172 nm from synchrotron radiation excitation. The Eu-doped MAl12O19 phosphor shows broad and strong absorption in VUV region and exhibits intensive emission in blue region. The CaAl12O19: Eu2+ shows strong blue emission band at 414 nm while in SrAl12O19:Eu2+ two emission peaks are observed at about 395 nm and another around 418 nm. Both CaAl12O19: Eu2+ and SrAl12O19:Eu2+ display two very weak red emission bands at 592, 613 and 591, 613 nm respectively due to co-existence of Eu3+. BaAl12O19: Eu2+ phosphor shows emission around 440 nm in the blue region of the spectrum.