Biphenylene-bridged mesostructured organosilica as a novel hybrid host material for LnIII (Ln = Eu, Gd, Tb, Er, Yb) ions in the presence of 2-thenoyltrifluoroacetone

Abstract

A hierarchically ordered 4,4′-biphenylene-bridged mesoporous organosilica framework (Bp-PMO) has been synthesized with the aim of using it as a new hybrid host for Ln^III ions. A series of novel organic–inorganic luminescent hybrid materials have been obtained by covalently linking Ln^III complexes (Ln = Eu, Gd, Tb, Er, and Yb) to Bp-PMO functionalized with 2-thenoyltrifluoroacetone (HTTA). The visible and NIR photoluminescence studies of the hybrid materials show that Bp-PMO acts both as an inorganic host and an organic co-sensitizer for Ln^III ions. The intrinsic quantum yield and lifetime data obtained for the hybrid material containing Eu^III (54.5% and 615 μs) are among the highest values reported for hybrid materials containing Eu^IIItetrakis(β-diketonate) complexes. The combination of Bp-PMO and HTTA also provides sizable sensitization for Tb^III, Er^III and Yb^III ions. The overall quantum yields and lifetime measurements for mixed metallic hybrid materials show that Ln → Ln′ energy transfer occurs in the mixed lanthanide systems. In addition, controlling the Ln/Ln′ ratio allows one to tune the emission colour.