Luminescence properties of tricellulose acetate composites emitting blue light

A series of dinuclear complexes with molar ratios of cerium to lanthanum of 1:0, 1:1, 1:2, 1:4, 1:7, 1:9 and 0:1 was synthesized using 5-sulfosalicylic acid (SSA) as the first ligand and 1,10-phenanthroline (Phen) as the second ligand, recorded as Ce_1−xLa_x(SSA)₃Phen (x = 0, 0·5, 0·67, 0·8, 0·875, 0·9, 1), and the complexes were blended with tricellulose acetate (TCA) to obtain luminescent polymer materials. The compositions and structures of the rare earth complexes were determined through elemental analysis, energy-dispersive X-ray analysis, infrared spectroscopy and thermogravimetric analysis. Under the optimum excitation wavelengths, all dinuclear complexes emitting blue light displayed the characteristic emission of the cerium (Ce³⁺) ion. The fluorescence spectra showed that the 85:15 TCA/Ce_0·2La_0·8(SSA)₃Phen composite showed the strongest fluorescence among all composites and the quantum efficiency was calculated as 30·6%. The introduction of the lanthanum (La³⁺) ion into the cerium ion complex can effectively reinforce the luminescence intensity of the complex and be favorable for retaining the excellent fluorescence in the TCA matrix. The 85:15 TCA/Ce_0·2La_0·8(SSA)₃Phen composite possesses fine luminescence properties and thermal stability for potential usage as a blue fluorescent material.