Improved photoluminescence of red‐emitting NaCaPO 4 :Eu 3+ phosphor by charge compensation

In this paper, we report the preparation of a red‐emitting NaCaPO 4 :Eu 3+ phosphor by the solid‐state method at 900 °C, also the effects of Eu 3+ concentration on its luminescent properties were investigated. To achieve charge compensation, additional Na + acting as a charge compensator was incorporated into the phosphor. Under near‐ultraviolet (UV) excitation, the luminescent properties as a function of additional Na + concentration were systematically studied with a fixed optimal Eu 3+ concentration. It was found that charge‐compensated phosphors showed greatly enhanced red emission at 619 nm, compared with the phosphor without charge compensation. Na 1.3 Ca 0.4 PO 4 :0.3Eu 3+ was deduced to be the best composition and its luminescent intensity was stronger than that of commercial red‐emitting phosphors for white light‐emitting diode application.The emission spectra of as‐prepared NaCa 0.7 PO 4 :0.3Eu 3+ (a), Na 1.3 Ca 0.4 PO 4 :0.3Eu 3+ (b), and commercial Y 2 O 2 S:Eu 3+ (c) phosphors excited by 395 nm.