Co-Precipitation Synthesis And Characterization Of YAG:Ce³⁺ Nano-sized Phosphor Particles

White light-emitting diodes (WLED) made up of InGaN chips and trivalent cerium activated yttrium aluminum garnet (YAG:Ce³⁺ ) phosphor is deemed to the most valuable new light sources in 21st century because of its several merits, such as: small size, long lifetime, rapid response, nonpolluting, high energy efficiency, high reliability, delicate design, ease of miniaturization, etc.YAG:Ce³⁺ phosphor nano particles with spherical morphology, homogeneous size and non-aggregation were prepared by co-precipitation instead of traditional preparation methods. The crystal structure and luminescence property of YAG:Ce³⁺ were mainly influenced by calcination temperature, sintering time, kind of precipitator, concentration of Ce³⁺, etc.The paper also discussed the mechanisms of red shift phenomena when other rare earth ions were doped in YAG:Ce³⁺ and provided the necessary theoretical basis for the development of luminescence technique. The main results of the thesis are as follows:1) Addition of trivalent terbium ions into YAG:Ce³⁺ phosphor host structure won't changes the microcosmic structure of the phosphor system,but induce the Ce³⁺ emission band to shift to 538 nm because of the larger crystal field splitting;2) In the system of Y2.96-xGdxAl5O12: Ce0.04,the dominative phase was cubic YAG when x was smaller than 1.5, with the increase of Gd³⁺ doping concentration, the main emission of the phosphor showed red shift: from 530nm to 548nm;3) Pr³⁺ addition to YAG:Ce³⁺ phosphor as co-activator resulted in sharp emission peak at about 610 nm through 1D2→3H4 transition. The color temperature of WLED can be depressed by doping Tb³⁺,Gd³⁺,Pr³⁺ into YAG:Ce³⁺ because the doping rare earth ions can add red component to the emission spectrum of the phosphors.