Fluorescence properties of polyaryletherketone rare earth-coordinated complexes in near-infrared region

Abstract

Novel rare earth-coordinated polymers were prepared using carboxyl-containing polyaryletherketone (PEK) as the macromolecular ligand and 8-hydroxyquinoline (HQ) as the co-ligand to coordinate with erbium (Er³⁺), neodymium (Nd³⁺) and ytterbium (Yb³⁺), respectively. The FTIR, elemental analysis, inductively coupled plasma, and UV-vis results confirm that the rare earth ions have been attached to the polymer backbone via a coordination bond. The complexes can emit the characteristic near-infrared fluorescence of the corresponding rare earth ions. Moreover, it is found that the synergistic effect of PEK and HQ can significantly enhance the emission intensities. In particular, for PEK-Er³⁺-HQ, the full width at half maximum (FWHM) of the ⁴I_13/2→⁴I_15/2 transition is up to 78 nm. The combination of strong fluorescence emission in the near-infrared range, high glass transition temperature and wide gain bandwidth provides promising potential for optical amplification applications.