Luminescence Properties of CaAl2O4:Eu3+, Gd3+ Phosphors Synthesized by Combustion Synthesis Method

N. Vermaa, K.C. Singh a, B. Marí b, M. Mollar b, J. Jindal a aDepartment of Chemistry, Maharshi Dayanand University, Rohtak 124001, Haryana, India bInstitut de Disseny per la Fabricació Automatitzada, Departament de Física Aplicada, Universitat Politècnica de València, Camí de Vera s/n, 46022 València, Spain

Received: August 22, 2016; In final form: October 9, 2017

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CaAl2O4:Eu3+ (1 mol.%) co-doped with varying concentration of Gd3+ (1, 2, 5, and 10 mol.%) were prepared by combustion synthesis method at 600°C and further annealed at 1000°C. All the compositions were investigated for their structural and photoluminescence properties. It was observed that both states of europium i.e. Eu3+ and Eu2+ were present and ratio of these states changes on heating at 1000°C. The materials synthesized at 600°C showed high intense peak around 440 nm due to presence of Eu2+ and less intense peaks in the red region which were due to presence of Eu3+. On annealing the compounds at 1000°C, intensity of peak around 440 nm decreases and intensity of peaks in the red region increases significantly. The 5D0→7F3 transition due to Eu3+ at 657 nm appears as the highest intensity peak. All co-doped samples annealed at 1000°C showed the higher intensity than the mono doped sample which is due to energy transfer from the Gd3+ to Eu3+. The second rare-earth ion (Gd3+) acts as sensitizer and enhances the photoluminescence intensity. The X-ray diffraction spectra reveal the monoclinic phase of CaAl2O4 in all the samples which showed that Eu3+ and Gd3+ do not change the crystalline structure of calcium aluminate.

DOI: 10.12693/APhysPolA.132.1261 topics: phosphors, luminescence, combustion method, calcium aluminate