Strain-Induced Enhancement of Eu3+ Emission in Red Phosphor NaMgPO4:Eu3+, Al3+
A series of (NaMgPO4)0.98−x: $${\hbox{Eu}}_{0.02}^{3 + }$$Eu0.023+, $${\hbox{Al}}_{x}^{3 + }$$Alx3+ phosphors were prepared by the solid-state method. X-ray powder diffraction results confirm that the samples contain mixture phases of crystals. The doped effect of Al3+ on the photoluminescence properties of (NaMgPO4)0.98−x: $${\hbox{Eu}}_{0.02}^{3 + }$$Eu0.023+, $${\hbox{Al}}_{x}^{3 + }$$Alx3+ phosphors is discussed. The results indicate that two dependent curves of emission relative intensity and strain on Al3+ doping concentration are all Gaussian curves, and a high correlation is observed between emission relative intensity of Eu3+ and strain caused by Al3+. In other words, emission relative intensity of Eu3+ is enhanced with the increase of the strain. The enhanced mechanism of the strain is discussed. In addition, (NaMgPO4)0.98−x: $${\hbox{Eu}}_{0.02}^{3 + }$$Eu0.023+, $${\hbox{Al}}_{x}^{3 + }$$Alx3+ phosphors are electric dipole-dominated transition red phosphors. The optimal molar concentration of Al3+ for the samples is 9%, which (NaMgPO4)0.89: $${\hbox{Eu}}_{0.02}^{3 + }$$Eu0.023+, $${\hbox{Al}}_{0.09}^{3 + }$$Al0.093+ is a potential candidate as the red-emitting phosphor for ultraviolet-based white light-emitting diodes.