Near UV excitable Eu-doped alumina nanophosphors synthesized by the microwave assisted solvothermal technique

• Published in: Materials research express 2017-12, Vol.4 (12), p.125007
• Main Authors: Padilla-Rosales, I, Cabañas-Moreno, J G, Jiménez, G L, Aguilar-Frutis, M A, Alarcón-Flores, G, Falcony, C
• Format: Article
• Language: English
• Subjects: microwave assisted solvothermal technique; photoluminescence; red light emission nanophosphors
• ISSN: 2053-1591; 2053-1591
• DOI: 10.1088/2053-1591/aa9b67

Europium doped alumina nanophosphors have been synthesized by the microwave assisted solvothermal technique. The dependence of the photoluminescence response and structural features of these nanophosphors on the europium content and annealing temperature has been characterized for a wide range of compositions and thermal treatments. The nanophosphors are composed of a mixture of nanocrystalline γ-Al2O3 and EuAlO3, in addition to an amorphous alumina phase. The relative quantities of each phase depend on both the europium content and the annealing temperature. High europium content and/or annealing temperature lead to larger fractions of EuAlO3 nanocrystals having with poor luminescence characteristics, while lower temperatures and europium contents result in the predominance of γ-Al2O3 nanocrystals and amorphous alumina, showing much more efficient luminescent emission. The luminescence spectra from all samples show the characteristic red emission peaks from the Eu3+ ion associated with inter-electronic energy level transitions. However, the excitation spectra in these nanophosphors are dominated, by the 7F0-5L6 transition (395 nm), as opposed to the dominant charge-transfer related band at ~260 nm commonly reported for this material. The highest luminescence intensity was obtained for nanophosphors doped with 7.5 at.% of Eu, annealed at 900 °C, which exhibits a quantum yield of 45% when excited with 395 nm light.