Preparation, characterization and luminescence properties of ternary europium complexes covalently bonded to titania and mesoporous SBA-15

Abstract

A novel multifunctional precursor Ti-MAB-S15 (MAB = meta-aminobenzoic acid) were prepared through the reaction of the carboxylic group with titanium alkoxide, and the amino group was modified with the coupling agent 3-(triethoxysilyl)-propyl isocyanate (TEPIC) and covalently bonded to mesoporous silica SBA-15. Then, novel organic–inorganic luminescent mesoporous hybrid titania materials, designated as Eu(Ti-MAB-S15)₂(NTA)₃, were obtained by introducing the Eu(NTA)₃·2H₂O (NTA = 1-(2-naphthoyl)-3,3,3-trifluoroacetonate) complex into the hybrid materials Ti-MAB-S15via a ligand exchange reaction. FTIR, SAXRD, N₂ absorption measurements, TEM, SEM, and photoluminescent spectra were characterized, and the results reveal that it has high surface area, is uniform in the mesostructure, and has good crystallinity. In addition, compared to the pure complex Eu(NTA)₃·2H₂O, the mesoporous hybrid titania material Eu(Ti-MAB-S15)₂(NTA)₃ exhibits longer luminescent lifetime and higher quantum efficiency, which indicates that the introduction of the multifunctional ligand Ti-MAB-S15 can sensitize the luminescence emission of the Eu³⁺ ions. Moreover, the luminescent mesoporous hybrid titania materials containing terbium ions, designated as Tb(Ti-MAB-S15)₂(NTA)₃, were also prepared, and were found to emit green photoluminescence characteristic of terbium ions.