Correlation of photoluminescence of (La, Ln) PO4:Eu3+ (Ln = Gd and Y) phosphors with their crystal structures

Eu3+-doped (La, Ln) PO4 (Ln = Gd and Y) phosphors were prepared by a facile co-precipitation method. Their structures and luminescent properties under UV excitation were investigated. Structural characterization of the nanostructured luminescence material was carried out with X-ray powder diffraction analysis. Scanning electron microscopy was carried out to understand the surface morphological features and grain sizes with 50–100 nm. It is found that (La, Gd) PO4:Eu3+ phosphors have the same crystal structure as LaPO4:Eu3+, which is monoclinic with a little different lattice parameters. In the case of (La, Y) PO4:Eu3+ phosphors, however, the gradual change from monoclinic to tetragonal structure of host lattice was observed, as the amount of Y ion increased. From the photoluminescence spectra for (La, Ln) PO4:Eu3+ (Ln = Gd and Y), the emission transition 5D0 → 7F1 has been found to be more prominent over the normal red emission transition 5D0 → 7F2. Furthermore, the size influence on the products was discussed. It was observed that the spectral features possess sharp and bright emission for potential applications on the monitors of the television and some other related electronic systems, in observing the images in orange–red color.