White-light emission from the quadruple-stranded dinuclear Eu(iii) helicate decorated with pendent tetraphenylethylene (TPE)

Abstract

White-light-emitting materials have attracted significant attention due to their broad applications in displays and lighting. Herein, a quadruple-stranded helicate with white-light emission was constructed by co-assembly of bis-β-diketone featuring cyan fluorescence and red light emitting Eu³⁺ ions in a 2 : 1 stoichiometric ratio. The cyan emission from bis-β-diketone originated from the pendent tetraphenylethylene (TPE), a typical AIE molecule featuring strong emission in the aggregation state. The formation of the helicate was verified by ¹H NMR, ¹H DOSY and high-resolution MS analyses. Upon excitation at 390 nm, the helicate realized the tunable emission with the colors changing from white light to green in the solid state. After hybridization with a polymer, a white-light hybrid material was prepared with the CIE coordinate locating at (0.322, 0.332). The absolute luminescence quantum yields were measured to be 16.9%.