Fluorescence-based monitoring of the pressure-induced aggregation microenvironment evolution for an AIEgen under multiple excitation channels

Abstract

The development of organic solid-state luminescent materials, especially those sensitive to aggregation microenvironment, is critical for their applications in devices such as pressure-sensitive elements, sensors, and photoelectric devices. However, it still faces certain challenges and a deep understanding of the corresponding internal mechanisms is required. Here, we put forward an unconventional strategy to explore the pressure-induced evolution of the aggregation microenvironment, involving changes in molecular conformation, stacking mode, and intermolecular interaction, by monitoring the emission under multiple excitation channels based on a luminogen with aggregation-induced emission characteristics of di(p-methoxylphenyl)dibenzofulvene. Under three excitation wavelengths, the distinct emission behaviors have been interestingly observed to reveal the pressure-induced structural evolution, well consistent with the results from ultraviolet-visible absorption, high-pressure angle-dispersive X-ray diffraction, and infrared studies, which have rarely been reported before. This finding provides important insights into the design of organic solid luminescent materials and greatly promotes the development of stimulus-responsive luminescent materials.

Tandem High-Pressure Crystallography–Optical Spectroscopy Unpacks Noncovalent Interactions of Piezochromic Fluorescent Molecular Rotors

“…However, the structure–fluorescence relationships in organic rotors are underdeveloped, limiting the synthesis of bespoke fluorophores with predictable and tunable fluorescence. Recently, Yu, Gao, and Gu have reported high-pressure photophysical measurement of AIE materials supported by angle-dispersive X-ray diffraction to measure changes in unit cell dimensions. , Here, we monitor structural changes at the molecular level, correlating precise changes in molecular geometry and intermolecular distances with optical properties of AIE materials through a combination of atomically resolved X-ray crystallographic measurements and electronic spectroscopy under high pressure. We examine the structure–fluorescence relationships in Ph 7 C 7 H by tandem single-crystal X-ray diffraction, fluorescence emission spectroscopy, and UV–visible absorption spectroscopy measurements under high hydrostatic pressure conditions.…”

Enhancing tetraphenylethene cyclization as photoswitch

“…Since first reported by Tang and coworkers in 2007, [1] tetraphenylethene (TPE) has promoted intense interest in the development of aggregation-induced emission (AIE) [2][3][4][5][6][7][8] applications such as theranostics, [9][10][11] chiral applications, [12][13][14][15][16] and also in the assembly of more complex structures. [17][18][19] Therefore, TPE is well regarded as a star AIE building block to date.…”

Anthracene–naphthylacetonitrile fluorescent isomers and Cl/H substituent dependent molecular packing, solid-state fluorescence and mechanofluorochromism

“…[26][27][28][29][30] Mechanical pressure can disrupt the supramolecular interactions, molecular conformation and packing that strongly affect the optical bandgap, resulting in the modulation of fluorescence. [31][32][33][34][35] Hence, several π-conjugated organic derivatives have been synthesized and reported for mechanical stimuli-induced reversible fluorescence switching between two fluorescence states (on-on) or change of fluorescence intensity (on-off). 3,[36][37][38] The planar anthracene aromatic unit has been successfully utilized as a building block for synthesizing solid-state and stimuli-responsive fluorescent materials.…”