Effect on the fluorescence branching ratio of different synergistic ligands in neodymium complex doped PMMA

A series of neodymium complexes Nd(TTA)3Lx (where TTA = α-thenoyltrifluoroacetonato, Lx (x = 1–5) = H2O, triophenylphosphine oxide (Tppo), 2,2-bipyridine (Bipy), 1,10-phenanthroline (Phen) and 2- (N,N-diethylanilin-4-yl)-4,6-bis(3,5-dimethylpyrazol-1-yl)-1,3,5-triazine (Dpbt) were synthesized and incorporated in poly(methyl methacrylate). Their absorption spectra were measured and analyzed using Judd–Ofelt theory. Near-infrared luminescent spectra were studied and the radiative properties have been stimulated. Laser parameters such as effective bandwidths (Δλeff), stimulated emission cross-sections (σe), and gain bandwidth (σg) had also been calculated and compared with other systems. The effect on the fluorescence branching ratio (β) in the 4F3/2→4I11/2 transition of different synergistic ligands had been investigated and the relation between β and Judd–Ofelt parameter Ω2, Ω4, Ω6 was discussed. In conclusion, among the five neodymium complexes, Nd(TTA)3Dpbt has the largest Ω2 parameter (33.72 × 10− 20 cm2), stimulated emission cross-sections, which is found promising to be a candidate for laser materials in further application.

► Neodymium complexes Nd(TTA)3Lx were synthesized and incorporated in PMMA.
► Absorption spectra were measured and analyzed using Judd–Ofelt theory.
► Their absorption spectra were measured and analyzed using Judd–Ofelt theory.
► Laser parameters had also been calculated.
► Fluorescence branching ratio (β) for the 4F3/2→4I11/2 transition depended on parameter Ω2, rather than parameter Ω4 and Ω6.