Luminescence studies of europium chelates with increasing benzene ring substituents ligand-doped polymer

The luminescence properties of four europium chelates with increasing benzene ring substituents ligand in poly(methylmethacrylate) (PMMA) have been investigated by fluorescence emission spectra and lifetime measurements. According to the fluorescence emission spectra, the Judd–Ofelt parameters Ω2, Ω4 of europium chelates-doped PMMA have been calculated and the radiative properties were also presented. It showed that the increase of benzene ring substituents in ligand can increase the metastable state lifetime τm, the luminescence quantum yield η and the stimulated emission cross-section σ of 5D0 → 7F2 transition.