Effect of cation substitution on luminescence properties of phosphor NaYPO4F:Ce3+: A comparison with LnPO4:Ce3+ (Ln = La and Y)

Phosphor NaYPO4F:Ce3+ was synthesized via a high-temperature solid-state reaction, and Na+ and Y3+ ion were partially replaced by Li+ and La3+ ion, respectively. X-ray diffraction patterns, excitation and emission spectra were recorded to investigate the phosphors. The phosphor shows a typical doublet emission of Ce3+ ion in the spectral range ~ 310-420 nm. The emission peak of Ce3+ ion at short-wavelength side gradually enhances when Li+ ion gradually substitute for Na+ ion. The emission peak at short-wavelength side gradually decline when La3+ ion gradually substitute for Y3+ ion. The different luminescence behaviors among NaYPO4F:Ce3+, YPO4:Ce3+ and LaPO4:Ce3+ also are simply discussed according to the Ce3+ coordination environment. The results show that high concentration of Li+ or La3+ ion results in the occurrence of a second phase YPO4 or LaPO4, and that the optimal concentration of Li+ and La3+ ion are 0.4 and 0.2, respectively.