Luminescence and Energy Transfer of Eu- and Mn-Coactivated CaAl<INF>2</INF>Si<INF>2</INF>O<INF>8</INF> as a Potential Phosphor for White-Light UVLED

A series of Eu²⁺- and Mn²⁺-coactivated CaAl<INF>2</INF>Si<INF>2</INF>O<INF>8</INF> phosphors have been synthesized at 1400 °C under a reduced atmosphere and their luminescence properties have been investigated as a function of activator and coactivator concentrations. We have discovered that energy transfers from Eu²⁺ to Mn²⁺ by directly observing significant overlap of the excitation spectrum of Mn²⁺ and the emission spectrum of Eu²⁺ as well as the systematic relative decline and growth of emission bands of Eu²⁺ and Mn²⁺, respectively. The critical distance and average separation of Eu²⁺ and Mn²⁺ have also been calculated. By utilizing the principle of energy transfer, we have also demonstrated that with appropriate tuning of activator content CaAl<INF>2</INF>Si<INF>2</INF>O<INF>8</INF>:Eu²⁺,Mn²⁺ phosphors exhibit great potential to act as a phosphor for white-light ultraviolet light-emitting diodes (UVLEDs).