Luminescent Eu3+/Tb3+ immobilized in 5-amino-iso-phthalate functionalized hybrid gels through di-urea bridge

5-Amino-iso-phthalic acid (AIPA) is modified with 3-(triethoxysilyl)-propyl isocyanate (TEPIC) to achieve special di-urea bridge (abbreviated as AIPASi) which behave as a linkage between Eu3+/Tb3+ and composite gels Si–O–M (M = Si, B, Ti) by controlling the hydrolysis rate of alkoxy compounds (tetraethyl orthosilicate (TEOS), titanium butoxide (TBT) and tributyl borate (TBB)). Subsequently, the Eu3+/Tb3+ covalently immobilized in AIPA functionalized composite gels are assembled and characterized and especially photoluminescent properties (luminescence spectroscopy, lifetimes and quantum efficiency) are discussed. The hybrids with composite Si–O–B gels possess the better photophysical properties than Si–O–Ti gels and even than pure silica gels.