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Fig. 2: (a) TEM micrograph of sample S2 and (b) SAED pattern of samarium doped silica
nanopowder.

The particle size reveals that highly purify sample has been synthesized after left out all

impurities due to thermal treatment at higher temperature. From TEM study, accumulation of
nanoparticles results in small increase in size as compared to particle size obtained via XRD.

Fig. 2(b) shows the selected area electron diffraction pattern of the samarium doped silica
nanopowder. One may notice a diffused ring-shaped SAED pattern in evidence of the mixed

phase of prepared sample [14]. We have obtained highly dense and perfectly crystalline

nanoparticles of Sm2O3 as examined by XRD and TEM result.
Ultraviolet-Visible Spectroscopy (UV-Vis.) Analysis

Absorption characteristics of pure crystalline materials is frequently dominated by the optical
nature of rare-earth ions embedded in silica or other glasses applicable for laser,

optoelectronic and biomedical applications. To study the movement of local environment

near the rare-earth ions using the sol-gel method, researchers frequently adopt UV-Vis
spectroscopy. Fig. 3 demonstrate the UV-Visible optical absorption spectra of Sm2O3

nanocrystallites dispersed in silica for both the annealed sample S1 and S2. From the Fig. 3
we can see that the sample S1 and S2 have strong absorption peak, respectively at 210 and

215 nm credited as hump of silica network. This silica hump shows slight shift towards the
higher wavelength region with slight increase in intensity known as red shift. Red shift

occurred in the annealed sample owing to change in the morphological, optical and surface

microstructure of the prepared sample [15]. The second most prominent peak at 275 and 280
nm for sample S1 and S2 attributed to the samarium ions incorporated in silica matrix. It can

2-
3+
be noticed that the peak at 280 nm is owed to charge transfer transition as O Sm in

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