Ca5La5(SiO4)3(PO4)3O2:Ce3+,Mn2+: A Color-Tunable Phosphor with Efficient Energy Transfer for White-Light-Emitting Diodes

A series of single-composition color-tunable phosphors Ca 5 La 5 (SiO 4 ) 3 (PO 4 ) 3 O 2 : Ce 3+ ,Mn 2+ (CLSPO:Ce 3+ ,Mn 2+ ) are synthesized by solid-state reaction, and their luminescence properties are investigated. The obtained phosphors exhibit high absorption and strong excitation bands in the wavelength range of 260–400 nm, matching well with the dominant emission band of a UV light-emitting-diode (LED) chip. The energy transfer from Ce 3+ to Mn 2+ ions in CLSPO:Ce 3+ ,Mn 2+ has been studied and demonstrated to be a resonant type via a dipole-quadrupole mechanism based on the decay lifetime data. The energy transfer efficiency as well as the critical distance are also estimated. Moreover, the phosphors can generate lights from blue through white and eventually to red by properly tuning the relative ratio of the Ce 3+ to Mn 2+ ions grounded on the principle of energy transfer. Preliminary studies show that CLSPO:Ce 3+ ,Mn 2+ can be a promising candidate for a single-phased color-tunable phosphor applied in a UV white-light LED.