INORGANIC PHOSPHORS IN GLASS BASED ON LEAD SILICATE GLASSES
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We created and synthesized luminescent composite of the "phosphor in glass" type, based on the lead-silicate matrix and fine-dispersed powder of cerium-activated yttrium-aluminum garnet crystal. Lead-silicate system (40SiO2- 20PbO-(40-x) PbF2-xAlF3, x = 0-25) was chosen as the glassy matrix. Initial glass was reduced to powder (frit) for "phosphor in glass" composite with a particle size about 50 µm. Glass frit and powder of commercial YAG:Ce3+ phosphor were mixed in a ratio of 30 to 70 (wt %). Then this composite was pressed in a tablet and sintered on a quartz substrate at 823 К for 30 minutes. Thus, the plane parallel sheet for composite of the "phosphor in glass" was obtained with a diameter equal to 10 mm. For the purpose to reduce the loss of light in the presence of dispersion at a glass-phosphor boundary, optimization of glass mixture was done by adjusting the refractive index. X-ray phase and spectral-luminescent analysis of the derived composite were done. The results of these studies showed that there was no degradation of YAG: Ce powder during sintering. Dependence of luminescence intensity from temperature in the range from room temperature to 473 К was studied. It was shown, that with the phosphor in glass usage thermal quenching of luminescence was reduced in comparison with the silicone. The model of white LED was created with the "phosphor in glass" composite based on lead-silicate glasses with low temperature of vitrifying. The derived LED emits white light with a color temperature of 4370 K, and the luminous efficiency is equal to 58 lm/W. The developed luminescent composite based on the lead-silicate matrix can be used for the production of high-power white light LED.
Acknowledgements. The work was partially financially supported by the state program for development of international scientific laboratories at ITMO University according to “Rules of grants distribution for the Russian Federation Government financial support of the leading universities aimed at their competitiveness growth among the chief world scientific educational centers”.
1. Shin-Etsu Silicone. Product Information [Электронный ресурс]. Режим доступа: http://www.silicone.jp/e/index.shtml, свободный. Яз. англ. (дата обращения 21.03.2014).
2. Zhao H., Liu G., Zhang J., Poplawsky J.D., Dierolf V., Tansu N. Approaches for high internal quantum efficiency green InGaN light emitting diodes with large overlap quantum wells // Optics Express. 2011. V. 19. N 14. P. A991–A1007.
3. Farrell R.M., Young E.C., Wu F., Denbaars S.P., Speck J.S. Materials and growth issues for highperformance nonpolar and semipolar light-emitting devices // Semiconductor Science and Technology. 2012. V. 27. N 2. Art. 024001
. 4. Zhang J., Tans N. Improvement in spontaneous emission rates for InGaN quantum wells on ternary InGaN substrate for light-emitting diodes // Journal of Applied Physics. 2011. V. 110. N 11. Art. 113110.
5. Ee Y.-K., Biser J.M., Cao W., Chan H.M., Vinci R.P., Tansu N. Metalorganic vapor phase epitaxy of IIInitride light-emitting diodes on nanopatterned AGOG sapphire substrate by abbreviated growth mode // IEEE Journal of Selected Topics in Quantum Electron. 2009. V. 15. N 4. P. 1066–1072.
6. Li X.H., Song R., Ee Y.-K., Kumnorkaew P., Gilchrist J.F., Tansu N. Light extraction efficiency and radiation patterns of III-nitride light-emitting diodes with colloidal microlens arrays with various aspect ratios // IEEE Photonics Journal. 2011. V. 3. N 3. P. 489–499.
7. Tanabe S., Fujita S., Sakamoto A., Yamamoto S. Glass ceramics for solid state lighting // Ceramic Transactions. 2006. V. 173. P. 19–25.
8. Fujita S., Sakamoto A., Tanabe S. Luminescence characteristics of YAG glass-ceramic phosphor for white LED // IEEE Journal on Selected Topics in Quantum Electronics. 2008. V. 14. P. 1387–1391.
9. Nishiura S., Tanabe S. Preparation and optical properties of Eu2+ and Sm3+ co-doped glass ceramic phosphors emitting white color by violet laser excitation // Journal of the Ceramic Society of Japan. 2008. V. 116. N 1358. P. 1096–1099.
10. Tsai C.-C., Cheng W.-C., Chang J.-K., Chen Y.-L., Chen J.-H., Hsu Y.-C., Cheng W.-H. Ultra-high thermalstable glass phosphor layer for phosphor-converted white light-emitting diodes // IEEE/OSA Journal of Display Technology. 2013. V. 9. N 6. P. 427–432.
11. Tsvetkova M.N., Korsakov V.G., Sychev M.M., Chernovets B.V., Itkinson G.V. Study of photophosphors for white LEDs // Journal of Optical Technology. 2011. V. 78. N 6. P. 403–407.
12. Tsai C.-C., Chung C.-H., Wang J., Cheng W.-C., Chen M.-H., Liou J.-S., Chang J.-K., Hsu Y.-C., Huang S.- C., Lee C.-W., Hu H.-L., Huang S.B., Kuang J.-H., Cheng W.-H. High thermal stability of high-power phosphor based white-light-emitting diodes employing Ce:YAG-doped glass // Proc. Electronic Components and Technology Conference. 2010. P. 700–703.
13. Tsai C.-C., Liou J.-S., Cheng W.-C., Chung C.-H., Chen M.-H., Wang J., Cheng W.-H. High humidity resistance of high-power white-light-emitting diode modules employing Ce:YAG doped glass // Proc. Electronic Components and Technology Conference. 2011. P. 1626–1630.
14. Lee Y.K., Lee J.S., Heo J., Im W.B., Chung W.J. Phosphor in glasses with Pb-free silicate glass powders as robust color-converting materials for white LED applications // Optics Letters. 2012. V. 37. N 15. P. 3276– 3278.
15. Allen S.C., Steckl A.J. A nearly ideal phosphor-converted white light-emitting diode // Applied Physics Letters. 2008. V. 92. N 14. Art. 143309.
16. Setlur A.A. Phosphors for LED-based solid-state lighting // Electrochemical Society Interface. 2009. V. 18. N 4. P. 32–36.