Synthesis of Nanosized Ce3+,Eu3+-Codoped YAG Phosphor in a Continuous Supercritical Water System

Luminescent yttrium aluminum garnet (Y 3 Al 5 O 12 ) nanoparticles codoped with Ce 3+ and Eu 3+ (YAG:Ce 3+,Eu 3+ ) were continuously synthesized by directly feeding potassium hydroxide solution and a metal salt solution to supercritical water (SCW). The effects of the Ce 3+ -to-Eu 3+ concentration ratio on the photoluminescence of the synthesized nanoparticles were studied using a continuous SCW tubular reactor. At 20-s reaction time and a pH of 9.10 in the SCW reactor, the average size of the prepared phosphor nanoparticles was 60−150 nm and cubic or hexagonal particles coexisted with the spherical particles. The phosphor nanoparticles presented a broad emission band in the green-yellow spectral region due to Ce 3+, as well as a sharp emission peak at around 610 nm in the red spectral region due to Eu 3+ . Without further thermal treatment, the YAG:Ce 3+,Eu 3+ phosphor synthesized in the continuous reactor under SCW conditions showed strong luminescence properties. Simultaneously, enhancement of the red spectral emission intensity in the YAG:Ce 3+,Eu 3+ phosphor could be controlled by increasing the Eu 3+ concentration.