Microstructures and luminescent regulation of Ce‐doped silicate glasses with high transmittance and thermal stability

Abstract

The traditional model for wLEDs usually encapsulates the phosphor and resin mixture on the InGaN blue-emitting chip. However, the poor thermal stability of silicone resin will lead to the reduction of the luminescent intensity of the wLED devices. Glass has excellent thermal stability and transparency, which is a promising alternative to resins. In this work, Ce-doped silicate luminescent glasses have been developed by a high-temperature melting quenching method in air atmosphere. The luminescent intensity can be enhanced by increasing the heat treatment temperature and extending the heat treatment time in 10%H 2 /Ar atmosphere because Ce 4+ ions can be reduced to Ce 3+ ions. However, when the heat treatment temperature reaches 850 • C, the generation of precipitates in the glass can reduce the luminescent intensity. The transmittance of glass can reach 87%, and the highest luminous intensity obtained when heat treated at 800 • C.The glass transition temperature is 740 • C and the thermal conductivity of the glass is .95 W m −1 K −1 , which is about five times higher than that of resin. The results show that the emerging Ce-doped silicate luminescent glass could be the potential material for wLED applications.

Improving white light emission and quantum yield of Ce@Eu co‐doped silicate glass by reducing Eu3+ to Eu2+ with Si3N4

“…White light‐emitting diodes (wLEDs) are widely used in daily lighting, display devices, biomedical, and other fields 1–3 because of its small size, non‐pollution, low cost, and high luminous intensity 4–10 . The commercial wLEDs combine YAG:Ce 3+ phosphors and an InGaN blue‐chip to achieve white light emission 1,11,12 .…”

“…White light-emitting diodes (wLEDs) are widely used in daily lighting, display devices, biomedical, and other fields [1][2][3] because of its small size, non-pollution, low cost, and high luminous intensity. [4][5][6][7][8][9][10] The commercial wLEDs combine YAG:Ce 3+ phosphors and an InGaN blue-chip to achieve white light emission. 1,11,12 However, YAG:Ce 3+ phosphors generally need to be mixed with an organic resin before being glued to the chip, 13 resulting in many fatal problems such as chemical unstability, 14 low thermal conductivity, 15 and easy to age 16 caused by the organic resin.…”