Optically controllable polarized luminescence from azopolymer films doped with a lanthanide complex

Abstract

Two azopolymers (DACENO₂ and DACEOCH₃) with a special structure were designed and synthesized. The azopolymer films doped with the lanthanide complex Eu(TTA)₃Phen were prepared by a casting method with a mixed solution of the azopolymer and lanthanide complex. UV-vis spectra show that the absorption peaks of the predesigned azopolymers DACENO₂ and DACEOCH₃ are separated from that of Eu(TTA)₃Phen. Under this circumstance, the photo-induced anisotropy of the films could not be destroyed by excitation and emission during fluorescence measurements. Polarized luminescence of both oriented films was observed with polarization ratios of 3.0 for the DACENO₂–Eu(TTA)₃Phen film and 2.7 for the DACEOCH₃–Eu(TTA)₃Phen film at 613 nm, respectively. The luminescent properties of the film were found to be affected by the chemical structure of the azopolymer, the extent of the photo-induced alignment and the angle between the orientated direction of the film and the direction of the polarizer. All the results from this work revealed that the polarized luminescence from the azopolymer film doped with a lanthanide complex can be controlled by the extent of photo-induced alignment.