Enhanced full color tunable luminescent lyotropic liquid crystals from P123 and ionic liquid by doping lanthanide complexes and AIEgen.

ABSTRACT

HYPOTHESIS: The soft materials from ionic liquid mediated lyotropic liquid crystals (LLCs) containing europium complexes have exhibited enhanced luminescence efficiencies and photo-stabilities. The combination with aggregation-induced emissive compounds (AIEgens), however, may produce multicolor and even white emitting LLCs. EXPERIMENTS Here, we have fabricated highly luminescent hexagonal (H1) LLC containing a red-emitting trisdipicolinate lanthanide complex [choline]3[Eu(DPA)3] (Eu-DPA) from Pluronic 123 and 1-butyl-3-methylimidazolium hexafluorophosphate (BmimPF6). Then, a typical AIEgen, tetrakis(4-hydroxyphenyl)ethane (TPE-OH) showing blue light was doped into H1 matrix, accompanying with a green-emitting Tb-DPA. FINDINGS: The emission color of such LLCs could be finely-tuned through changing the molar ratio of Eu-DPA to Tb-DPA. Remarkably, the white emitting H1 LLC with CIE coordinate of (0.328, 0.315) has been prepared by accurately adjusting the relative contents of TPE-OH, Eu-DPA and Tb-DPA. Further, the emission color could be switched between bright white and blue upon tuning UV light from 254 to 365 nm repeatedly. To our best knowledge, such full color tunable luminescent LLCs with improved luminescent performances for both AIEgen and lanthanide complexes have not been reported. This facile approach is universal and various kinds of luminophores can be thus encapsulated into LLC matrices to fabricate soft materials with rich luminescent properties.