High quantum yield of red-emitting Eu3+doped nanophosphor based on monoclinic Y2O3

In the present article we report on the laser synthesis of Eu3+ doped nanophosphor with improved red color based on single-phase monoclinic Y2O3 and an experimentally measured quantum yield as high as 60% at lambda = 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 degrees C. The thermal annealing effects in air and vacuum in the range of 250-750 degrees C on the morphology, structure, optical and photoluminescence properties of as-synthesized m-Y2O3:Eu3+ 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 Y2O3:Eu3+ in numerous luminescence applications.