Near-infrared luminescence of periodic mesoporous organosilicas grafted with lanthanide complexes based on visible-light sensitization

A new periodic mesoporous organosilica material (named as bpd-PMO) was synthesized through co-condensation of bis(triethoxysilyl) ethane (BTEE) and a synthesized silsesquioxane precursor 4,4'-bis [Si(OEt)(3)(CH2)(4)]-2,2'-bipyridine (bpd-Si) in the presence of cetyltrimethylammonium bromide (CTAB) surfactant as template. Subsequently, three near-infrared (NIR) luminescent PMO hybrid materials (named as Ln(dbm)(3)bpd-PMO, Ln Er, Nd, Yb) covalently linked with lanthanide complexes were successfully prepared via a ligand exchange reaction. The materials were characterized by XRD, N-2 adsorption-desorption isotherms, SEM, and fluorescence spectra, and the corresponding luminescent decay analyses were recorded. Of importance here is that the excitation spectra of the Ln(dbm)(3)bpd-PMO extend to the visible-light range. Following the visible-light excitation, the Ln(dbm)(3)bpd-PMO materials show the characteristic NIR-luminescence of the corresponding Ln(3+) ions. The good NIR-luminescence properties of the Ln(dbm)(3)bpd-PMO with the visible-light excitation would extend the potential applications of the PMO matrix to the NIR optical field.