Investigation of thermal quenching process in Eu2+ or Ce3+-doped phosphors for white LED applications

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K05934
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Inorganic industrial materials
• Research Institution: Kyoto University
• Principal Investigator: UEDA JUMPEI 京都大学, 人間・環境学研究科, 助教 (90633181)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 蛍光体 / 白色LED / 消光 / 熱イオン化 / 電子移動

Outline of Final Research Achievements

Recently, white LEDs have started to be use as indoor illumination instead of incandescent lamp and fluorescent tube. The white LED is composed of blue LED and visible phosphors. Due to the heat generation of high power white LEDs, the thermal quenching of phosphors are becoming a problem. Although there are two possible quenching processes, thermal ionization and thermally activated cross-over, the mechanism is not clear in almost all phosphors.
In this study, we investigated the quenching mechanism of some phosphors and concluded that almost all phosphors with 5d-4f transition is thermally quenched by thermal ionization process.

Free Research Field

無機化学

Academic Significance and Societal Importance of the Research Achievements

近年、白色LEDの高出力化が進み、発熱量が増えたため、可視蛍光体の強度が温度により低下する温度消光が問題である。本研究では、その温度消光プロセスを明らかにできたため、その温度消光プロセスを低減できる材料設計指針を得ることに成功した。これにより、より高出力のLED励起に耐え得る蛍光体が今後開発できる可能性が高くなった。