A novel red emitting polymeric complex as a directly film-forming phosphor applied in NUV-based LEDs

Abstract A novel red emitting polymeric complex poly(styrene-co-glycidyl methacrylate)-Eu(TTA)2(Phen) (PS-co-PGMA-Eu) as a directly film-forming phosphor was synthesized by the technological means of polymerization and subsequent coordination using Eu(TTA)2(Phen) as the complex precursor and poly(styrene-co-glycidyl methacrylate) (PS-co-PGMA) as macromolecular ligand. The synthesized polymeric phosphor can be easily cast into uniform and smooth films. Aside from high thermal stability, this kind of optical material shows a wide-band excitation with the optimum excitation wavelength at 365 nm. Excited by 365 nm UV-light, the intensity of characteristic emission peak at 612 nm of polymer phosphors with different complex content is up to 4 times higher than that of complex. The sensitization effect of the polymer matrix on the luminescent center Eu3+ is discussed in detail. For the polymer phosphor, the concentration of complex could be as high as 7.5 wt % without obvious fluorescence quenching. Furthermore, The polymer phosphor has high quantum yield (67.04%) and long fluorescence lifetime (0.685 ms). Finally, red emitting LEDs fabricated by directly film-forming encapsulation displays better electroluminescent performance (maximum brightness is 12120 cd/m2). In conclusion, PS-co-PGMA-Eu is a promising directly film-forming red emitting polymeric phosphor for NUV-based LEDs.