Study of Red-Emission Piezochromic Materials Based on Triphenylamine

Photophysical Analysis of Aggregation-Induced Emission (AIE) Luminogens Based on Triphenylamine and Thiophene: Insights into Emission Behavior in Solution and PMMA Films

Aggregation-Induced Emission (AIE) luminogens have garnered significant interest due to their distinctive applications in different applications. Among the diverse molecular architectures, those based on triphenylamine and thiophene hold prominence. However, a comprehensive understanding of the deactivation mechanism both in solution and films remains lacking. In this study, we synthesized and characterized spectroscopically two AIE luminogens: 5-(4-(bis(4-methoxyphenyl)amino)phenyl)thiophene-2-carbaldehyde (TTY) and 5'-(4-(bis(4-methoxyphenyl)amino)phenyl)-[2,2'-bithiophene]-5-carbaldehyde (TTO). Photophysical and theoretical analyses were conducted in both solution and PMMA films to understand the deactivation mechanism of TTY and TTO. In diluted solutions, the emission behavior of TTY and TTO is influenced by the solvent, and the deactivation of the excited state can occur via locally excited (LE) or twisted intramolecular charge transfer (TICT) state. In PMMA films, rotational and translational movements are constrained, necessitating emission solely from the LE state. Nevertheless, in the PMMA film, excimers-like structures form, resulting in the emergence of a longer wavelength band and a reduction in emission intensity. The zenith of emission intensity occurs when molecules are dispersed at higher concentrations within PMMA, effectively diminishing the likelihood of excimer-like formations. Luminescent Solar Concentrators (LSC) were fabricated to validate these findings, and the optical efficiency was studied at varying concentrations of luminogen and PMMA.

A Cost-Effective Way to Produce Gram-Scale 18O-Labeled Aromatic Aldehydes

Obtaining ¹⁸O-labeled organic substances is of great research importance and also an extremely challenging work. In this work, depending on the reversed Knoevenagel reaction, ¹⁸O-labeled aromatic aldehydes (3a-3x) are successfully obtained with high total yields (52-72%) and sufficient ¹⁸O abundance (90.90-96.09%).

Acceptor–donor–acceptor-linked triphenylamine and phenothiazine motifs as cousin molecules: the methyl effect on stimuli-responsiveness, crystallochromism, and dual-state emission

Bulky/twisted triphenylamine or phenothiazine linked dicyanoaniline is synthesized to achieve dual-state emitters with crystallochromic and multi-stimuli responsive behaviour. The effect of methyl group on emission is also identified.

A water-soluble fluorescent sensor for the quick discrimination of H2O and D2O by notable signal outputs and the real-time monitoring of food spoilage in a non-contact mode

Due to the very similar chemical and physical properties, D2O and H2O cannot be discriminated easily by convenient and cost-effective ways.

Mechanochromic Fluorescent Polymers with Aggregation-Induced Emission Features

Mechanochromic polymers are defined as materials that are able to detect a mechanical stress through an optical output. This feature has evoked a growing interest in the last decades, thanks to the progress of chromogenic molecules whose optical characteristics and chemical functionalities allow their effective insertion in many thermoplastic and thermoset matrices. Among the different types of fluorogenic probes able to detect mechanical solicitations, those with aggregation-induced emission (i.e., AIEgens) have attracted tremendous interest since their discovery in 2001. In the present review, the main principles behind the AIEgens working behavior are introduced along with the current state of knowledge concerning the design and preparation of the derived mechanochromic fluorescent polymers. Examples are provided concerning the most ingenious solution for the preparation of chromogenic materials, starting from different types of commodity plastics or synthetic polymers and combined with the latest AIE technology to provide the most sensitive response to mechanical stress.

Facile synthesis of AIEgens with wide color tunability for cellular imaging and therapy

Luminogens with aggregation-induced emission (AIE) characteristics are nowadays undergoing explosive development in the fields of imaging, process visualization, diagnosis and therapy. However, exploration of an AIE luminogen (AIEgen) system allowing for extremely wide color tunability remains challenging. In this contribution, the facile synthesis of triphenylamine (TPA)-thiophene building block-based AIEgens having tunable maximum emission wavelengths covering violet, blue, green, yellow, orange, red, deep red and NIR regions is reported. The obtained AIEgens can be utilized as extraordinary fluorescent probes for lipid droplet (LD)-specific cell imaging and cell fusion assessment, showing excellent image contrast to the cell background and high photostability, as well as satisfactory visualization outcomes. Interestingly, quantitative evaluation of the phototherapy effect demonstrates that one of these presented AIEgens, namely TTNIR, performs well as a photosensitizer for photodynamic ablation of cancer cells upon white light irradiation. This study thus provides useful insights into rational design of fluorescence systems for widely tuning emission colors with high brightness, and remarkably extends the applications of AIEgens.

Synthesis of tunable, red fluorescent aggregation-enhanced emissive organic fluorophores: stimuli-responsive high contrast off–on fluorescence switching

Molecular conformation controlled tunable and stimuli-responsive off–on fluorescence switching.

An easily accessible aggregation-induced emission probe for lipid droplet-specific imaging and movement tracking

An easily accessible aggregation-induced emission (AIE) probe is developed for LD-specific imaging and dynamic movement tracking with advantages of NIR two-photon excited red emission and fast cell permeability.