Tricolor- and White Light-Emitting Ce/Tb/Mn-Coactivated LiCaSiO Phosphor via Energy Transfer.

Single-component tunable LiCaSiO:Ce,Tb,Mn phosphors were successfully synthesized at 950 °C. LiCaSiO:Ce,Tb exhibits two luminescence peaking at 430 and 550 nm, which originated from the allowed 5d → 4f transition of the Ce ion and the D → F ( = 6, 5, 4, 3) transition of the Tb ion, respectively. Moreover, by codoping Ce ions in the LiCaSiO:Mn system, yellow-red emission from the forbidden transition of Mn could be enhanced. Under UV excitation, dual energy transfers (ETs), namely, Ce → Mn and Ce → Tb, are present in the LiCaSiO:Ce,Tb,Mn system. The ET process was confirmed by the overlap of the excitation spectra, variations in the emission spectra, ET efficiency, and decay times of phosphors. In addition, quantum yields and CIE chromatic coordinates are presented. The emission color of these phosphors can be tuned precisely from blue to green via ET of Ce → Tb and from blue to yellow via ET of Ce → Mn. White light can also be achieved upon excitation of UV light by properly tuning the relative composition of Tb/Mn. This result indicates that the developed phosphor may be regarded as a good tunable emitting phosphor for UV light-emitting diodes.