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Detailed Program
Paper Number : GL-I01
Time Frame : 10:45~11:10
Presentation Date : Thurse day, 27, November
Session Name : Glass& Opto-Electronic Meterials
Session Chair 1# : Yong Gyu Choi
Session Chair 2# : Atsunobu Masuno
Glass materials for white LED color converters
Woon Jin CHUNG
Kongju National University
Conventional light emitting diodes are composed of blue LED chip and yellow phosphors as a color converter which is embedded with organic resins. Due to weak thermal and chemical stability of organic resins which restricts the lifetime of white LEDs, inorganic color converters have been extensively studied recently. Inorganic color converters can be classified as phosphor ceramics (PC), phosphor glass ceramics (PGC), phosphor in glass (PiG) and bulk glass phosphor (BGP). Three of them are glass based materials which shows the importance of glass materials. In this talk, after brief introduction of inorganic color converters for white LED and their recent achievements, various results on PiGs and BGPs will be introduced.
For PiGs, various silicate glass systems were studied to lower the sintering temperature below 600 oC to embed red phosphors. SiO2-B2O3-P2O5-RO, SiO2-B2O3-ZnO-R2O and SiO2-Na2O-RO systems were investigated. Glass compositions which can be sintered under 550 oC were found and successful color tuning was achieved by incorporating additional red phosphors along with the improvement of the color rendering index. Oxyfluoride glasses with LaF3 nano-crystals were also studied for BGP. Eu2+ and Eu3+ doped oxyfluoride glass showed some possibility for color conversion when it was heavily crystallized. Silicate glasses with quantum dot were also investigated as a blue LED color converter. CdS, CdSe and CdSSe QDs were formed within glass matrix and CdSe and CdSSe showed possible color converting properties when they were mounted on LED chips.
Acknowledgements : This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2013R1A1A2005671).