The reduction of Eu3+ to Eu2+ in a new orange–red emission Sr3P4O13: Eu phosphor prepared in air and its photoluminescence properties

A new orange–red phosphor Sr3P4O13: Eu was synthesized by a high temperature solid-state reaction. X-ray powder diffraction (XRD) analysis confirms the formation of Sr3P4O13 in a triclinic system with space group View the MathML sourceP1¯. The photoluminescence spectra indicate that Sr3P4O13: Eu can be excited effectively by near ultraviolet (NUV) light and exhibit bright orange–red emission with excellent color stability. Interestingly, the emission bands of Eu2+ and Eu3+ were both observed in the photoluminescence spectra of air-sintered Sr3P4O13: Eu phosphor due to the self-reduction effect. This kind of abnormal reduction was explained by a charge compensation model.