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

Abstract

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)3bpd-PMO, Ln = Er, Nd, Yb) covalently linked with lanthanide complexes were successfully prepared via a ligand exchange reaction. The materials were characterized by XRD, N2 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)3bpd-PMO extend to the visible-light range. Following the visible-light excitation, the Ln(dbm)3bpd-PMO materials show the characteristic NIR-luminescence of the corresponding Ln3+ ions. The good NIR-luminescence properties of the Ln(dbm)3bpd-PMO with the visible-light excitation would extend the potential applications of the PMO matrix to the NIR optical field.