Preparation and Properties of Low Melting Temperature Phosphor Glass Thick Films for White LEDs

Abstract:

Using commercial low melting temperature glass (LMTG) powders, Ce doped Y₃Al₅O₁₂ (Ce: YAG) and acrylic resin as raw materials, LMTG with Ce: YAG phosphor films for high-power white LEDs have been successfully prepared through silk-screen printing and low-temperature melt-quenching method. The LMTG with Ce: YAG phosphor thick films were studied by Differential Scanning Calorimeter, X-ray Diffraction, Photoluminescence Spectrum, and so on．The results showed that the crystal structure of Ce: YAG phosphor was formed after sintering, the glass phase was still the major phase in low melting temperature phosphor glass (LMTPG) thick films; The glass transition temperature of LMTPG films are around 305 ℃, and their glass melting temperature are around 450 ℃, both of them were significantly lower than ordinary glass. The emission peaks are a broad emission band that the center is located at 553 nm under the wavelength of 441 nm blue light excitation. the chromaticity coordinate was calculated to be (0.3794, 0.4296),the LE is 115.5 lm/W and the IE is 76.2 %. The research results indicated that the LMTPG films can be a novel promising material without any organic principle for high- power white LEDs．