Starburst Triarylamine Donor–Acceptor–Donor Quadrupolar Derivatives Based on Cyano‐Substituted Diphenylaminestyrylbenzene: Tunable Aggregation‐Induced Emission Colors and Large Two‐Photon Absorption Cross Sections

Abstract

In this work, we have developed a new class of aggregation-induced emission (AIE) active compounds, in which three electron-donating diphenylamine, phenothiazine, or carbazole groups are connected to the 1, 4-positions of the benzene through bis(α-cyano-4-diphenylaminostyryl) conjugation bridges to form three triarylamine quadrupolar derivatives (3 a-c). Their one- and two-photon absorption properties have been investigated. The two-photon absorption (2PA) cross sections measured by the open-aperture Z-scan technique were determined to be 1016, 1484, and 814 GM for 3 a-c, respectively. From this result, the high 2PA properties of these molecules are attributed to the extended π system and enhanced intramolecular charge transfer from the starburst triarylamine to the cyano group. Moreover, cyano-substituted diphenylamine styrylbenzene (CNDPASB)-based compounds are very weakly fluorescent in THF, but their intensities increase by almost 230, 70, and 5 times, respectively, in water/THF (v/v 90 %) mixtures, in which they exhibit strongly enhanced red, orange, and deep yellow fluorescence emissions, respectively. This result indicates that the intramolecular vibration and rotation of these dyes is considerably restricted in nano-aggregates formed in water, leading to significant increases in fluorescence. It was found that the color tuning of the CNDPASB-based compounds could be conveniently accomplished by changing the starburst triarylamine donor moiety. Multilayer electroluminescence devices with TPBI (2,2',2''-(benzene-1,3,5-triyl)-tri(1-phenyl-1H-benzimidazole)) electron-transporting layers have been made, with 3 a and 3 c as a non-doping red-yellow emitter. The preliminary results for these multilayer devices show a maximum efficiency of 0.25 %, and electroluminescence (EL) wavelengths around 568 nm. The excellent 2PA and AIE properties of these compounds make them potential materials for biophotonic applications.

Design and synthesis of theranostic antibiotic nanodrugs that display enhanced antibacterial activity and luminescence

“…2D). These observations are consistent with many other AIE-active luminogens having donor-acceptor structures (21,22,37,(39)(40)(41), where the aggregation hampers the intramolecular motion between the donor and the acceptor, hence leading to enhanced fluorescent emission as well as a blue shift in the emission peak (15). Spherical nanoaggregates were observed at high water content (≥99 vol %) (Fig.…”

Theoretical and Experimental Spectroscopic Analysis of Cyano-Substituted Styrylpyridine Compounds

“…On the other hand, it is well know that cyano-substituted compounds show good optical and electrical properties due to their high electron affinities [9]. In particular, some cyano-substituted compounds have been reported, which show unique enhanced emission rather than fluorescence quenching in the solid state [10]. However, pyridine is an important electron-acceptor group, due to its high electron affinity.…”

Tetraphenylethene end-capped diketopyrrolopyrrole fluorogens with AIE and large two-photon absorption cross-sections features and application in bioimaging

“…The s was calculated by the equation of s ¼ hvb/N 0 , and the b is the 2PA coefficient, which can be obtained by the Z-scan data fitting, as shown in Fig. 5 (1ae1d) [36,37].…”