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

Rare-earth-doped transparent glass shows great potential in white light-emitting diodes (wLEDs) application due to its excellent optical and luminous properties. Currently reported commercial wLEDs have a drawback in red emission missing, which leads to a relatively low color rendering index (CRI) and a relatively high correlated color temperature (CCT). In this work, Ce@Eu Sr–Si–O glass is fabricated using a high-temperature quenching method. The white light is available when the ratio of Ce 3+ /Eu 3+ equals 1, and the emitting color can be adjusted from blue to red by controlling the ratio of Ce 3+ /Eu 3+ . To further optimize the white light, Eu 3+ ions can be reduced to Eu 2+ according to the reaction of 6Eu 3+ + 2N 3− → 6Eu 2+ + N 2 ↑ by introducing Si 3 N 4 . As a result, the standard white light emission can be achieved in the Ce@Eu silicate glass contributed by the blue light from Ce 3+ , red light from Eu 3+ , and yellow–green light from Eu 2+ (two elements, three emission). This glass shows excellent luminous properties, such as a color coordinate is (0.3651, 0.3269) in CIE 1931 color coordinate diagram, a CRI is over 70, a high quantum yield of 36.02%, and a CCT of 4117 K.