Antenna Effect in Highly Luminescent Eu3+ Anchored in Hexagonal Mesoporous Silica

A route for coordination of Eu3+ by dibenzoylmethane (DBM) covalently bonded inside hexagonal mesoporous silica was established here to produce the highly luminescent nanomaterial SiDBM−Eu(DBM)2. Thermogravimetry, luminescence, X-ray diffraction, N2 adsorption, FTIR, FTRaman, 29Si NMR, and 13C NMR in solid-state techniques were used to characterize SiDBM−Eu(DBM)2. The 29Si NMR spectrum proved that the DBM was covalently bonded to a silica framework. Thermogravimetric and titration data showed the 6.4 × 10-2 mmol of Eu3+ per gram of silica, and each Eu3+ is coordinated by three DBMs in SiDBM−Eu(DBM)2. SEM images confirmed that this material is formed by nanoaggregates with 200 nm diameter. N2 adsorption isotherms showed the SiDBM−Eu(DBM)2 complex with 800 m2 g-1 and 6.4 nm of porous diameter, characterizing mesoporosity of this nanomaterial. SiDBM−Eu(DBM)2 showed an efficient DBM to Eu3+ intramolecular energy process, namely, antenna effect, which favored a highly luminescent behavior in this modified hexa...