Single-phase white light emission Ca9NaLu0.667(PO4)7: Eu2+, Mn2+ phosphor for the application of WLED

Abstract

A single-phase full-spectrum emission Ca9NaLu0.667(PO4)7 (CNLP):Eu2+/Mn2+ phosphor was synthesized through the reaction to the solid state reaction at high temperature. CNLP:Eu2+ exhibits cyan light-emitting, and the luminous color of CNLP:Eu2+,Mn2+ has been adjusted from cyan then to white and finally to red by changing the content of Mn2+. The occupancy of Eu2+/Mn2+ was also analyzed by calculating the average bond length obtained using the Rietveld refinements. The energy transfer process (ET) of Eu2+ → Mn2+ was discussed in detail, and the ET efficiency could be as high as 77.81%. The internal quantum yield (QY) value of CNLP:2%Eu2+,3%Mn2+ is 49.51% at the excitation of 360 nm. CNLP:2%Eu2+,3%Mn2+ has a good thermostability. The white light-emitting diode (WLED) device showed warm white emission, which represented a low correlated color temperature (CCT) and high color rendering index (Ra). Moreover, the CCT and Ra remain within a certain range under different currents and temperatures, further demonstrating the potential application of WLEDs. These results prove that CNLP:2%Eu2+,1%Mn2+ phosphor has potential applications in the field of WLED.