Molecular assembly of novel luminescent terbium hybrid materials with modified 5-ethylpyridine-2,3-dicarboxylic acid as a functional bridge through an in situ sol-gel process

Molecular-type luminescent terbium containing hybrid materials were fabricated on the basis of modified 5-ethylpyridine-2,3-dicarboxylic acid by (3-aminopropyl)triethoxysilane (PDA-Si), emission centers and inorganic hosts. PDA-Si was demonstrated to show double functions which are utilized to coordinate to Tb3+ through carbonyl groups and covalently bonded with hosts by Si-O bonds after hydrolysis and polycondensation processes simultaneously. Ultraviolet absorption, phosphorescent spectra, and luminescent spectra were investigated to characterize the photophysical properties of the obtained hybrid material. It was shown that the triplet state energy of modified 5-ethylpyridine-2,3-dicarboxylic acid matches with the emissive energy level of Tb3+. More importantly, We unexpectedly observed some branches like morphology perhaps due to the formation tendency of 1-D chain crystal structure in original complex of 5-ethylpyridine-2, 3-dicarboxylic acid. The strong green fluorescence of terbium ions indicates that the molecular-designed hybrids have high photonic potential.