Multicolor Fluorescence Writing Based on Host–Guest Interactions and Force‐Induced Fluorescence‐Color Memory

Abstract

A new strategy is reported for multicolor fluorescence writing on thin solid films with mechanical forces. This concept is illustrated by the use of a green-fluorescent pentiptycene derivative 1, which forms variably colored fluorescent exciplexes: a change from yellow to red was observed with anilines, and fluorescence quenching (a change to black) occurred in the presence of benzoquinone. Mechanical forces, such as grinding and shearing, induced a crystalline-to-amorphous phase transition in both the pristine and guest-adsorbed solids that led to a change in the fluorescence color (mechanofluorochromism) and a memory of the resulting color. Fluorescence drawings of five or more colors were created on glass or paper and could be readily erased by exposure to air and dichloromethane fumes. The structural and mechanistic aspects of the observations are also discussed.

Heat‐Resistant Mechanoluminescent Chromism of the Hybrid Molecule Based on Boron Ketoiminate Modified Octasubstituted Polyhedral Oligomeric Silsesquioxane

“…The luminescentp roperties of organicf luorophores in the solid state can be occasionally affected by molecular distributions and morphology.W hen luminescent chromism was induced by mechanical stimuli, such as pressing,c rushing, and grinding,t hese molecules are classified as mechanoluminescent chromic (MLC) compounds. [1][2][3][4][5][6][7] Because of the potential versatility of MLC materials, such as for optical recording/ memory devices, [8] pressure indicators, [9] stress detectors with polymers, [10] and bioprobes for monitoring microenvironmental changes, [11,12] not only the development of MLC compounds, but also modulation of luminescent properties, such as color, intensity,a nd chromism direction,are hot topics with high relevance.H owever,b ecause most conventional luminescent dyes intrinsically show weake mission in the solid state due to aggregation-causedq uenching (ACQ), there are limited numbers of molecular skeletons with clear MLC behavior.I ndeed, it is still challengingt op recisely regulate MLC properties according to preprogrammed design.O ne of the promising candidates to produce MLC compounds with functional tunability is the class of aggregation-inducede mission [13][14][15][16][17][18][19][20] (AIE)-active molecules, which can show bright emission only in the aggregated state. [21] In particular, recent studies reported that vari-ous types of solid-state fluorescent materials with stimuliresponsive fluorescentc hromism involving MLC could be prepared based on the regulation of electronic conjugation through AIE-active organoboron complexes.…”

Recent advances in fluorescent film sensing from the perspective of both molecular design and film engineering

“…28 The fluorescence of the film can be changed from yellow to red when different anilines are introduced, whereas the presence of benzoquinone vapor will quench the fluorescence. For example, Yang et al fabricated a thin solid film by using a green fluorescent pentiptycene derivative.…”

Solid‐State Photochromism by Molecular Assembly of Bis‐o‐carboranyl Siloles

“…In recent years, diverse solid-state photochromism mechanisms have been reported,a nd among them, reversible mechanofluorochromism [1][2][3][4][5] has attracted special attention for its applications in sensors, [6,7] memory devices, [8][9][10] security inks, [11] and opticaldevices. [12][13][14][15] To develop new types of solid-statep hotochromism, as uitable organic or inorganic photofunctional group must be proposed.…”