An intense blue-emitting phosphor for near-ultraviolet pumped white-light-emitting diodes: Ce3+-activated β-Ca2SiO4

More recently, Ce3+ activated γ-Ca2SiO4 has been reported and it shows great potential application as a yellow-emitting phosphor for white LEDs. However, β-Ca2SiO4, another known phase of Ca2SiO4, doped with Ce3+ is not available. It is interesting to know if β-Ca2SiO4:Ce3+ can also be suitable for white LEDs. For this reason, we synthesized a series of β-Ca2SiO4:Ce3+ phosphors by solid state reaction. β-Ca2SiO4:Ce3+ exhibits an intense blue emission band peaked at 425 nm with a bandwidth of 68 nm which is attributed to the typical Ce3+ 4f05d1→4f1 transitions. The integral intensity of the concentration-optimized β-Ca2SiO4:Ce3+ can be as high as 71% of the commercial BAM blue phosphor upon 360 nm excitation. The excitation spectra of β-Ca2SiO4:Ce3+ consist of three broad bands with maxima at 252, 289 and 348 nm , which are ascribed to the 4f1→4f05d1 transitions of Ce3+. Thermal quenching property of β-Ca2SiO4:Ce3+ was evaluated and the results show that the integral PL intensity at 150 °C maintains about 93% of that at room temperature. The excellent thermal stability and intense emission upon NUV light excitation suggest that β-Ca2SiO4:Ce3+ can be used as a potential blue-emitting phosphor for NUV white LEDs.