Effect of Sr on the luminescence properties of Eu3+ activated xZnO-(1-x) SrO-Al2O3 phosphors

Abstract

Europium-doped xZnO-SrO-Al2O3 (x = 0, 0.2, 0.4, 0.5, 0.6, 0.8, 1) phosphors were synthesized by the traditional Solid-State Reaction (SSR) method. The structure of the phosphors prepared was analysed with the x-ray diffraction technique. The xZnO-(1-x) SrO-Al2O3:Eu3+ (0.1 mol%) (x = 0, 0.2, 0.4, 0.5, 0.6, 0.8, 1) exhibits varying PL intensity and is maximum for 0.8ZnO-0.2SrO-Al2O3: Eu3+ (0.4 mol%) and hence treated as the most prominent phosphor among these combinations. In the photoluminescence spectrum of the phosphors prepared, a sequence of emission bands were visible at various wavelengths viz., 576, 586, 602, 620, 656 and 702 nm as a result of the transitions of Eu3+ ions [5D0 - 7Fj where (j = 0–4)] and an excitation spectrum at 620 nm. An efficient orange-red phosphor thus developed capable of yielding a quantum efficiency of about 12%. Studies revealed that the commercially available red phosphors having an efficiency of only 9.6% (λex = 394 nm) & 4.2% (λex = 395 nm). Hence the current sample could be an ideal alternative for an efficient phosphor near UV LEDs. The mechanoluminescence of the 0.8ZnO-0.2SrO-Al2O3: Eu3+ (0.4 mol%) phosphor was also measured. The phosphor composition was analysed using XPS. The present paper also reports the thermoluminescence and OSL properties of Europium doped Zinc Strontium Aluminate phosphor at different gamma-ray dosages. Peak shape method was employed to evaluate kinetic parameters like activation energy, frequency factor and symmetry factor.