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

Abstract

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.

Security use of bilayer dichroic films made of liquid crystal polymer networks

“…As a result, as θ changed from 0°to 90°, the observed transmission color of each film changed from red and cyan to almost transparent. These results are the same as those for the conventional dichroic dye-doped LC films [1][2][3][4][5][6][7][12][13][14][15][16][17][18][19]. However, when their optical axes were stacked in a crossed manner, the transmission color changed differently from that of the single-layer film (Figure 2(a,d)).…”

“…Polarization-dependent liquid crystal (LC) films have been applied in broad fields, including in LC polarizers [1][2][3][4][5], photo-luminescence films [6][7][8], and photonic crystals [9][10][11]. Among these, dye-doped LC films composed of coaligned LC polymer networks and dichroic dyes attract interest among researchers due to their novel optical property and efficient fabrication process [1][2][3][4][5][6][7][12][13][14][15][16][17][18][19]. These films, also called 'host-guest LC films,' absorb maximum light when the polarization direction of the incident linear polarized light (LPL) and the absorption axes of the dichroic dyes are parallel.…”

Photoswitchable Fluorescent Liquid Crystal Nanoparticles and Their Inkjet‐Printed Patterns for Information Encrypting and Anti‐Counterfeiting

“…Meanwhile, the LC components stabilize the FM4 molecules in a well‐dispersed condition within the nanocolloids. As is well known that, dicyanodistyrylbenzene‐based compounds are very ideal choice for multifunctional materials due to their remarkable optical and electrical properties that derive from their designable chemical structures . The unique AIEE effect makes them have an extensive application in condense states.…”

Crystal structure and Hirshfeld surface analysis of 1-[(E)-2-(5-chloro-2-hydroxyphenyl)hydrazin-1-ylidene]naphthalen-2(1H)-one

“…Apart from their use as colourants, azo compounds have attracted a lot of attention from chemists as their potential applications are important in coordination chemistry (Asha & Mandal, 2018), metal-organic frameworks (MOFs) (Huang et al, 2017), covalent-organic frameworks (COFs) (Chandra et al, 2014) and catalysis (Choudhary et al, 2017). In addition, they have found many applications in different fields such as non-linear optics (Dudek et al, 2020), optical storage (Kovalchuk et al, 2020), photoluminescence (He et al, 2019), chemosensors (Akram et al, 2020) and magnetism (Nandi et al, 2021). They are used not only in physics but also in the biomedical and pharmacological fields as they can offer new therapeutic properties such as antiviral (Chhetri et al, 2021), antimicrobial (Kyei et al, 2020), anti-inflammatory and antioxidant (Unnisa et al, 2020).…”