Optical properties of MAl12O19:Eu (M = Ca, Ba, Sr) nanophosphors

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 615 nm. 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.