Tricolor- and White Light-Emitting Ce3+/Tb3+/Mn2+-Coactivated Li2Ca4Si4O13 Phosphor via Energy Transfer

Single - componenttunable Li2Ca4Si4O13:Ce3+, Tb3+, Mn2+ phosphors were successfully synthesized at 950 degrees C. Li2Ca4Si4O13: Ce3+, Tb3+ exhibits two luminescence peaking at 430 and 550 nm, which originated from the allowed 5d -> 4f transition of the Ce3+ ion and the D-5(4) -> F-7(J) (J = 6, 5, 4, 3) transition of the Tb3+ ion, respectively. Moreover, by codoping Ce3+ ions in the Li2Ca4Si4O13: Mn2+ system, yellow-red emission from the forbidden transition of Mn2+ could be enhanced. Under UV excitation, dual energy transfers (ETs), namely, Ce3+ -> Mn2+ and Ce3+ -> Tb3+, are present in the Li2Ca4Si4O13: Ce3+, Tb3+, Mn2+ 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 Ce3+ -> Tb3+ and from blue to yellow via ET of Ce3+ -> Mn2+. White light can also be achieved upon excitation of UV light by properly tuning the relative composition of Tb3+/ Mn2+. This result indicates that the developed phosphor may be regarded as a good tunable emitting phosphor for UV light-emitting diodes.