Structural, thermal and optical properties of Tb3+, Eu3+ and co-doped (Tb3++Eu3+): PEO+PVP polymer films

Abstract

Tb3+ and Eu3+ each ion individually doped and also both these ions doped in PEO+PVP blended polymer films have successfully been synthesized using solution casting method. XRD analyses of these films have demonstrated that those are in semi-crystalline nature. In order to understand their thermal properties, TG–DTA profiles have also been carried out. Fourier transform infrared (FTIR) and Laser Raman Spectra have been used to monitor polymer–salt complex formation, ion–polymer interactions. The polymer films containing Tb3+ and Eu3+ (0.1wt%) ions have displayed green (Tb3+) and red (Eu3+) luminescent colors under an UV source. Their absorption spectra, excitation and emission spectra have also been measured to evaluate their optical properties. For a prominent green emission at 546nm (5D4→7F5) of Tb3+ doped polymer film, and for a prominent red emission at 618nm (5D0→7F2) of Eu3+ polymer film, their emission transition lifetimes have been measured. Eu3+ emission intensity becomes significantly enhanced via an energy transfer from Tb3+ to Eu3+ in co-doped Eu3++Tb3+ polymer films. Thus, based on the results it could be suggested that Tb3+:PEO+PVP, Eu3+:PEO+PVP and (Eu3++ Tb3+):PEO+PVP blended polymer films as potential luminescent optical materials.