Enhanced luminescence of rare-earthTb (III) by Tm (III) in bis(benzoylmethyl)sulfoxide complexes and intra-molecular energy transfer

摘要

Rare-earth complexes (Tb_xTm_y)L_5(ClO_4)_2(ClO_4)·3H_2O(x:y = 1.000:0.000, 0.999:0.001, 0.995:0.005,0.990:0.010, 0.950:0.050, 0.900:0100, 0.800:0.200, 0.700:0.300: L = C_6H_5COCH_2SOCH_2COC_6H_5) weresynthesized and characterized with elemental analysis, infrared spectra (IR) and ~1H NMR. Thephotophysical properties of these complexes were studied in detail with ultraviolet absorption spectra,fluorescent spectra and lifetimes. The fluorescence spectra and decay curves of complexes indicated thatthe fluorescence emission intensity was enhanced and the fluorescence lifetime was prolonged by Tm(Ill), which may be due to the intra-molecular energy transfer between inert rare-earth ions and activerare-earth ions. The complexes showed the best properties when the mole ratio of Tb (III) to Tm (III) is0.995:0.005. The intensity of fluorescence can be increased to 208. Additionally, the energy-transfermechanisms between the ligand and the central Tb (III) ions were discussed.