Luminescent properties of low-temperature-hydrothermally-synthesized and post-treated YAG:Ce (5%) phosphors

• Obtainment of single phase YAG:Ce (5%) at low temperature.
• Enhancement of YAG:Ce (5%) emission by suitable post-treatment.
• Observation of emission peak red-shift for hydrothermally prepared YAG:Ce (5%).

YAG:Ce (5%) phosphors were synthesized by a hydrothermal method at 360 °C in a series of reaction times tr of 6, 10, 14, 18, 22 and 26 h, respectively. The single-phase YAG:Ce (5%) can be obtained at much lower temperature of 360 °C, compared with the conventional solid-state method and the other wet-chemical methods. The hydrothermally prepared sample with tr = 22 h was subsequently treated by spark plasma sintering (SPS), in vacuum and in air. The emission intensity of YAG:Ce (5%) sensitively depended on the post-treated methods and the related mechanism was discussed. As a contrast, the luminescence spectra of solid-state-reacted YAG:Ce (5%) was also measured, which exhibited an emission peak at 540 nm. However, the emission peak of hydrothermally prepared YAG:Ce (5%) red-shifted to 557 nm, which is useful in white light-emitting diode lighting sources.

Figure (a) shows the emission spectra (λex = 460 nm) of samples prepared by hydrothermal method (sample A) and post-treated in air (sample B), by SPS (sample C) and in vacuum (sample D). The emission intensity was increased about twofold by the proper post-treatments. Figure (b) shows the emission spectra (λex = 460 nm) of samples prepared by hydrothermal and solid-state methods. Compared with the solid-state reacted sample, the hydrothermally prepared YAG:Ce (5%) exhibited more intensive emission with a red-shift of emission peak from 540 nm to 557 nm, which is more suitable for a warm w-LED.Figure optionsDownload high-quality image (100 K)Download as PowerPoint slide