High quantum yield of red-emitting Eu 3+ doped nanophosphor based on monoclinic Y 2 O 3

In the present article we report on the laser synthesis of Eu 3+ doped nanophosphor with improved red color based on single-phase monoclinic Y 2 O 3 and an experimentally measured quantum yield as high as 60% at λ  = 395 nm excitation. HRTEM and SEM studies evidence the formation of nanoparticles with a spherical morphology, the average diameter of ca. 20 nm, and high crystallinity. We demonstrate that such a high quantum yield can be achieved by adding oxygen during laser synthesis in a combination with post-synthesis treatments in air at T = 750 °C. The thermal annealing effects in air and vacuum in the range of 250–750 °C on the morphology, structure, optical and photoluminescence properties of as-synthesized m -Y 2 O 3 :Eu 3+ have been discussed. The obtained chromaticity coordinates (0.659, 0.332), high color purity (96%) and high absolute quantum yield indicate the possibility of using red nanophosphor based on monoclinic Y 2 O 3 :Eu 3+ in numerous luminescence applications.