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

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+ (0.1 wt%) 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 546 nm (5D4→7F5) of Tb3+ doped polymer film, and for a prominent red emission at 618 nm (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.