CHEM01200604004 Shri Sanyasinaidu Boddu - Homi Bhabha ...

diffraction patterns from the GaPO 4 nanoparticles match well with the pattern reported in
JCPDS data. The lattice parameters were calculated and are found to be a = 4.900(2) Å and c
= 11.041(3) Å with a unit cell volume 229.5(2) Å 3 for un-doped GaPO 4 nanoparticles. The
lattice parameters are unchanged with increase in Eu 3+ content in the sample suggesting that
GaPO lattice is unaffected by increase in Eu 3+ concentration in the sample.
4
(d)
Intensity (arb.units)
(c)
(b)
(a)
20 30 40 50 60 70
2θ/°
Fig.54. XRD patterns of (a) hexagonal GaPO 4 standard corresponding to JCPDS file no.
080497 (b) GaPO 4 nanoparticles, (c and d) GaPO4 nanoparticles with 2.5 and 5 at %
Eu 3+ , respectively.
The average crystal size of GaPO 4 nanoparticles was calculated from the line width of
highest intense XRD peak by using Debye–Scherrer formula and is found to be ~ 30 nm. The
particle size is also unaffected by increasing the Eu 3+ contents in GaPO 4 samples. From the
XRD results, it can be inferred that Eu 3+ ions are not replacing Ga 3+ ions in GaPO 4 lattice.
Had it been the case, the lattice parameters of GaPO 4 nanoparticles would have increased
3+ 3+
significantly due to the higher ionic radii of Eu (0.947Å) compared to Ga (0.62Å) [172]. In
order to characterize the nanocrystalline nature of the above samples detailed TEM studies
have been carried out.
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