Dual-mode multi-color circularly polarized luminescent MOFs from a facile approach of chiral induction

Abstract

Metal–organic frameworks (MOFs) have attracted exclusive attention for several practical applications. However, rapid and handy preparation of functional MOFs with circularly polarized luminescence (CPL) has rarely been reported. In this work, by adopting chiral induction reagents, we elaborately constructed multi-color CPL-active lanthanide MOFs (Ln-MOFs, Ln³⁺ = Eu³⁺, Tb³⁺) by mechanical stirring at room temperature. Color-tuning from green to red was achieved by changing the content of Eu³⁺ and Tb³⁺ in the precursors. Moreover, upconversion nanoparticles (UCNPs) were encapsulated into chiral Ln-MOFs by in situ synthesis. The chiral perturbation affected achiral UCNPs to obtain induction chirality. Under the excitation of ultraviolet (UV) light and near-infrared (NIR) light, dual-mode CPL based on downshifting CPL (DS-CPL) and upconversion CPL (UC-CPL) in the solid-state was achieved. Our work provided a general approach for facile preparation of multi-color CPL-active solid-state materials and realized functional expansion, which broadened the research scope of the CPL-active solid-state materials.