Luminescence properties of terbium doped poly(acrylic acid) containing 1,10-phenanthroline and 2,2′-bipyridine

Abstract Tb 3+ -doped poly(acrylic acid) was synthesized by polymerization in aqueous solution of the monomer partially neutralized with Tb 2 O 3 , using potassium persulfate as initiator. Besides, samples containing Tb 3+ and 1,10-phenanthroline (Phen) or 2,2′-bipyridine (Bipy) ligands were synthesized. 13 C NMR confirmed the monomer modification and coordination of ligands to Tb 3+ . The doped polymer was characterized by Fourier transform infrared (FT-IR) and luminescent spectroscopy. The results showed clear evidence of the coordination between the dopant cations and the carboxylate anions from the polymer, which were formed during the partial neutralization of the monomer prior to polymerization, and confirmed the coordination of Phen or Bipy ligands to Tb 3+ . On the other hand, the broadening and the relatively high intensity of the 5 D 4 → 7 F 5 green emission of Tb 3+ indicate that the dopant ions are uniformly distributed in low symmetry coordination sites into the polymer matrix. Additionally, the complex formation of Tb 3+ and Phen or Bipy resulted in a prominent enhancement in the Tb 3+ emissions attributed to antenna effect, defined as the excitation of the ligands by light absorption and efficient energy transfer from the ligands to the Tb 3+ ions. The luminescent results showed that, for these polymeric materials, the antenna effect of Phen is even better than that of Bipy.