Synthesis and concentration dependent tuning of PVA-Sm2O3 nanocomposite films for optoelectronic applications

The concentration dependent structure and optical properties of PVA:Sm2O3 nanocomposite films are reported here. The nanoparticles of Sm2O3 were synthesized by solution combustion method and nanocomposite films by solution casting technique. X-ray diffraction studies show that the Sm2O3 nanoparticles are monoclinic in structure with the average crystallite size of 30 nm. Top view SEM images show that the dopants are distributed in the cluster form all over the PVA matrix. The changes in the peak intensity and the shifts in the peak position in the FTIR measurements confirm the incorporation of the dopant in the PVA film. The absorption spectra in the UV-visible region show that the Urbach energy (0.72 eV-1.46 eV) increases with increasing concentration of the dopant. The photoluminescence emission spectra of all the composite films exhibit three bands centered at 562 nm, 606 nm and 650 nm arising from electronic transitions of Sm3+. The intensity of the most intense emission band at 606 nm increases with increasing concentration of the dopant in the film upto 6 wt% and then decreases for 10 wt%. The color purity of the 2 wt%, 4 wt%,6 wt% and 10 wt% samples obtained from the CIE coordinates were found to be 68.16%, 63.67%, 58.06% and 56.06% respectively in the orange-red region. These results suggest that the PVA-Sm2O3 nanocomposite films are promising candidates for optical applications such as filters and red light emitting diodes.