Highly Miscible Hybrid Liquid-Crystal Systems Containing Fluorescent Excited-State Intramolecular Proton Transfer Molecules

Abstract

Doping of luminescent molecules in a nematic liquid-crystal (LC) host is a convenient approach to develop light-emitting LC displays that would be a promising alternative to conventional LC displays. The requirements for the luminescent guest molecules include high miscibility in the host LC, high-order parameters in the host LC media to show anisotropic luminescence, lack of self-absorption, transparency in the visible region, and a large photoluminescence quantum yield independent of its concentration. To address these issues, here, we newly synthesize a highly miscible and fluorescent excited-state intramolecular proton transfer molecule, C 4 -CC-HBT, based on 2-(2-hydroxyphenyl)­benzothiazole (HBT). This compound is highly miscible in a conventional room-temperature nematic LC 4-pentyl-4′-cyano biphenyl (5CB) up to 14 wt % (∼12 mol %) and exhibits a large photoluminescence quantum yield of ΦFL = 0.32 in the 5CB host, both of which were achieved by the introduction of an alkynyl group into the HBT core. C 4 -CC-HBT possesses a high-order parameter of S = 0.46 in 5CB, and the C 4 -CC-HBT/5CB mixtures show anisotropic fluorescence whose intensity is controlled by the applied electric field. A patterned image is demonstrated, which is not visible under an ambient environment but is readable upon UV illumination, relying on the orientational differences of ordered C 4 -CC-HBT molecules.

Principles of Aggregation‐Induced Emission: Design of Deactivation Pathways for Advanced AIEgens and Applications

“…In fact, some mechanisms of AIEgens have been reported that are based on a coordinate including double bond torsion and ring puckering. Theoretical investigations have suggested an involvement of double‐bond‐torsion‐type CIs in AIEgens such as diphenyldibenzofulvene ( DPDBF ), cyano‐substituted distyrylbenzene ( DBDCS ), and 2‐(2‐hydroxyphenyl)benzothiazole ( HBT ) . Ring‐puckering‐type CIs have also been found in tetraphenylsilole ( DMTPS ) and BDAA …”

Programming multicolour micro-patterns via regional polymer-stabilized heliconical soft architecture

“…As a passive reflective device, such a pattern consumes less power with reflecting ambient light, which is a significant advantage compared to an emissive/backlit display. 45–47 Consequently, such a system is expected to be utilized as a structural colour anti-counterfeiting label, in which the flexibly designed colour combination facilitates the integration of the anti-counterfeiting label with the background colour of commodity packaging.…”

“…As a passive reflective device, such a pattern consumes less power with reflecting ambient light, which is a significant advantage compared to an emissive/backlit display. [45][46][47] Consequently, such a system is expected to be utilized as a structural colour anti-counterfeiting label, in which the flexibly designed colour combination facilitates the integration of the anti-counterfeiting label with the background colour of commodity packaging. The fade-resistant, high saturation, wide colour gamut, high resolution, and especially reversible modulation performance of the patterned heliconical soft architecture inspired us to further explore potential applications in information encryption and encoding.…”

Amplified spontaneous emission from a liquid crystalline phase: anisotropic property and active modulation

“…24,[28][29][30][31][32] Based on the representative ESIPT molecular motif of 2-(2hydroxyphenyl)-benzothiazole (HBT), we designed a rod-like molecule with high aspect ratio: 2-(4-(1-hexynyl)-2-hydroxyphenyl)-benzothiazole (C4alkyne-HBT) showing relatively high uorescence quantum yield in various media. 33 In this work, the detailed optical properties of C4alkyne-HBT in liquid crystalline media: 4-pentyl-4 ′ -cyano biphenyl (5CB) have been studied as well as demonstrating anisotropic emission properties and dynamic control of the emission and optical gain.…”