Ce:YAG transparent ceramics for applications of high power LEDs: Thickness effects and high temperature performance

Ce doped Y3Al5O12 (Ce:YAG) transparent ceramics could be combined with blue chips of high power output, for applications of high power white light emitting diodes (LEDs). In this paper, we found that through the thickness variation of Ce:YAG transparent ceramics, emission spectrum and the color coordinates of the assembled LEDs could be adjusted from cold white to warm white light region. Ce:YAG transparent ceramics showed extraordinary high temperature quenching properties, they even kept almost 90% of initial luminescence intensity (room temperature) at temperature of 200 degrees C, which are superior to both the commercial yellow phosphors and white LEDs. By a far infrared temperature detecting system, the surface temperature of the assembled LEDs was recorded and compared to commercial ones, Ce:YAG transparent ceramics with higher thickness showed lower surface temperature, and Ce:YAG transparent ceramics also showed lower surface temperature than commercial white LEDs. Ce:YAG transparent ceramics combined to blue chips seems a good candidate for next generation high power light sources. (C) 2014 Elsevier B.V. All rights reserved