RESUMEN
Circularly polarized luminescence (CPL)-active materials with high dissymmetry factor (glum) values show great potential in photonic devices. In this study, electric-field-driven systems with tunable CPL signals are successfully fabricated based on polymer-stabilized cholesteric liquid crystal (PSChLC) doping by fluorescent molecules. By constructing a gradient helical superstructure of PSChLCs, distinctive CPL emission from two sides of a single sample is realized, in which the |glum| values were measured to be 0.6 and 1.5, respectively. Herein, we discussed the possible mechanism of this phenomenon. In addition, an applied electric field could broaden the reflection bandwidth of PSChLCs from 150 to 500 nm, covering the whole visible light region. Furthermore, this electric field-induced behavior leads to the variation of CPL signals and corresponding glum values, indicating the potential of the novel materials in the design and preparation of CPL-emitting devices with electrically tunable CPL intensity and glum.
RESUMEN
There is currently an extensive demand for simple and effective synthetic methods to allow the design and fabrication of robust and flexible chiral materials that can generate strong and switchable circularly polarized luminescence (CPL). Herein, biosynthetic light-emitting adhesive materials based upon chiral nematic cellulose nanocrystal-polyelectrolyte complexes with universal high adhesion on both hydrophilic and hydrophobic substrates are reported. Strong and dynamic photoluminescence with highly asymmetric and switchable circular polarization is induced by minute rare earth europium doping without compromising adhesive strength and initial iridescent properties. The photoluminescence can be temporarily quenched with highly volatile acetone vapor and liquid followed by fast recovery after drying with full restoration of initial emission. The unique properties of light-emitting bio-adhesives with universal adhesion, amplified and dynamic photoluminescence, and large and switchable CPL can be utilized for security optical coding, bio-optical memory, hidden communication, and biochemical sensing as wearable stickers, prints, and tattoos to directly adhere to human clothes, gadgets, and skin by using adhesive stickers with bright tailored photoluminescence.