Nanostructures and Photoluminescence Properties of Gd2O3:Eu Red-Phosphor Prepared via Hydrothermal Route

摘要

Various nanostructures(nanorods,nanowires,nanotubes,nanospheres)of Gd_(0.96)Eu_(0.04)(OH)3 have been prepared by hydrothermal reactions at different pHs and temperatures.The aspect ratios of one-dimensional nanostructures are strongly dependent on the solution pH.Subsequent dehydrations of these hydroxides at higher than 500 °C lead to the formation of Gd2O3:Eu phosphors with different nanostructures.Interestingly,the shapes of nanorod and nanowire obtained under hydrothermal pressures are retained after the structural transformation from hexagonal Gd(OH)3:Eu to cubic Gd2O3:Eu at high temperatures.Gd2O3:Eu nanowires can grow up to 20-30 nm in diameter and several tens of micrometers in length.In contrast,the nanotube structure of Gd(OH)3:Eu is collapsed to produce the spherical Gd2O3:Eu nanoparticles after dehydration process.A significant change of morphology induced by an adjustment of pH of the initial solution for hydrothermal synthesis of Gd(OH)3 :Eu strongly affect the photoluminescence efficiency of Gd2O3 :Eu phosphor.The relative emission intensity of Gd2O3:Eu is reduced with increasing the aspect ratio of nanoparticles,the weakest emission being observed with nanowires of the highest aspect ratio.