Photoinduced Dual-Mode Luminescent Patterns in Dicyanostilbene-Based Liquid Crystal Polymer Films for Anticounterfeiting Application

Tunable photoluminescence is highly favored for its unique in light emitting displays, bioimaging, and optoelectronic device fields. Here, a photoinduced dual-mode luminescent pattern in the dicyanostilbene monomer (DCN-M)-based liquid crystal polymer (LCP) films is first proposed by combining a photoinduced alignment with a photoisomerization reaction. The high polarized emission patterns at microscopic and macroscopic scale are first achieved by employing sulfonic azo dye (SD1) as an alignment agent to control the local orientation of highly emissive DCN-M in LCP matrix. Furthermore, by taking advantage of Z/E photoisomerization of the dicyanostilbene moiety in the DCN-M-doping LCP film, the photoluminescence intensity of the LCP film could be tuned upon nonpolarized ultraviolet light irradiation, thus enabling alternating light and dark regions in the LCP film. Finally, we proposed a proof-of-concept demonstration of a dual-mode emission pattern in a single LCP film for an anticounterfeiting application with modulation of both polarization and photoluminescence intensity. This work paves a new way for the fabrication of complex patterned fluorescent polymers for photonic applications.