Synthesis and fluorescence properties of reddish-orange emitting (Y, Ga)PO4: Sm3+ powder phosphors

(Y1-x-y, Ga-x)PO4: Sm-y(3+) (where 0.2375 <= x <= 0.95; y = 0.05 moles), powder phosphors have been synthesized through a novel co-precipitation technique, followed by calcination. The produced phosphors have been characterized by various spectroscopic techniques. From the XRD patterns, it is confirmed that the produced phosphors possess good crystalinity with tetragonal phase. The evidence for phosphate functional groups was investigated by Fourier transform - Infrared (FT-IR) spectra. Scanning electron microscopy (SEM) measurement reveals that the crystallite shape and size of the phosphors have been prominently dominated by the host composition (Y, Ga)PO4. YPO4: Sm3+ phosphor has shown spindle like shape crystallites, (Y, Ga)PO4: Sm3+ phosphors are in a gel type leafy shape and GaPO4: Sm3+ has shown agglomerated particles of spherical shape with an average crystallite size, at around 100 nm. These phosphors have exhibited strong reddish ((G)(5/2) -> H-6(9/2)) - orange ((4)G(5/2) -> H-6(7/2)) color, upon UV- excitation. From the fluorescence spectra, it is obvious that the gallium content has strongly influenced the fluorescence behavior of these phosphors. On the basis of fluorescence and pertinent optical properties the phosphor with composition Y0.95PO4: Sm-0.05(3+) has suggested to be an appropriate luminescent material for their use in certain optical display devices for reddish-orange emission.