Judd-Ofelt, radiative properties of Sm3+ ions doped PVA+PEG complex polymer films from spectral analysis

Abstract

A trivalent rare earth ion Sm3+ (1-5 mol %) doped Poly (vinyl alcohol) (PVA) and Poly (ethylene glycol) (PEG) complex polymer blends were synthesized by using solution casting technique. The spectroscopic characteristics behaviour and Judd-Ofelt (J-O) intensity parameters, oscillatory strengths and radiative properties of the prepared polymer blends were investigated with the help of optical absorption and photoluminescence spectral studies. Well defined UV-VIS-NIR optical absorption bands pertaining Sm3+ ions are observed in optical absorption spectrum and these bands has been assigned to their respective electronic transitions. The theoretical oscillatory strengths (f cal) and Judd-Ofelt (J-O) network framing theory were adopted to evaluate J-O intensity parameters Ω λ (λ=2,4,6) from the experimental oscillatory strengths (f exp). The covalent characteristic nature of the Sm3+ ions with surrounding ligands within the host polymer matrix was confirmed through bonding parameter (δ). The coordinated environment of Sm3+ ions and the key significant J-O intensity parameters are used for calculation of spectroscopic radiative properties. Photoluminescence spectrum is obtained and the highly intensified emission peak is observed for the transition 4G5/2→6H7/2 at 595 nm under 401 nm excitation wavelengths. The CIE colour coordinate diagram shows that the present complex polymer films incorporated with Sm3+ ions are acting as perfect and highly stable material for active reddish-orange emissions.