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Luminescent materials with multiple emission centers are attracting more and more attentions due to their potential applications in multicolor displays, polychromatic imaging, information encryption, and ratiometric chemical sensing. Organic molecules with phosphorescence behavior at room temperature (RTP) provide idea candidate for constructing luminescent materials with multiple emission centers, which show great potentials for application in ratiometric chemical sensing owing to its long‐lived emission and high signal‐to‐noise ratio. However, developing RTP materials with multiple emission centers and their application in aqueous solutions remains a huge challenge. Herein, two chromophore isomers (p‐N‐DPC·(PF6)2 and m‐N‐DPC·(PF6)2) based on carbazole and naphthalene units are prepared by using pyridine quaternary ammonium salt as link to improve their solubility in water and form electron deficient centers to facilitate charge transfer (CT). p‐N‐DPC·(PF6)2 displayed multiple emissions behavior, including monomer fluorescence, dimer fluorescence, monomer phosphorescence, dimer phosphorescence, and CT phosphorescence. Especially, p‐N‐DPC·(PF6)2 exhibits monomer fluorescence, dimer fluorescence, and CT phosphorescence in an aqueous solution, which is successfully applied as self‐calibrated dual ratio luminescent sensor for phosphate detection. This study not only provides a strategy to construct luminophore with multiple emissions but also develops a fluorescence/ phosphorescence dual ratio luminescent sensor in an aqueous solution. [ABSTRACT FROM AUTHOR]

Photoactivated dynamic ultralong room‐temperature phosphorescent (PAD‐URTP) materials with changing emission colors are attractive and meaningful but are rarely reported. Herein, a one‐pot heat treatment strategy for embedding 1‐hydroxy‐2‐naphthoic acid (1H2NA) and 2‐hydroxy‐1‐naphthoic acid (2H1NA) into boric acid (BA) matrix (named 1H2NA@BA and 2H1NA@BA) to construct PAD‐URTP materials is developed, which exhibits rapid and reversible photoactivated phosphorescence, as well as photo‐stimulated dynamic change of luminescence color. The luminescent color of 1H2NA@BA could continuously change from blue‐purple to bright cyan‐white upon prolonged 365 nm UV light irradiation, which is attributed to the combined effect of static blue fluorescence and dynamic photoactivated green phosphorescence. Significantly, it could emit over 10 s green afterglow after switching off the UV irradiation. The combination of experiment and theoretical calculation results reveal that their PAD‐URTP behavior is attributed to the energy accumulation of triplet states under UV light irradiation. Finally, a series of information encryption and a complete story of "a mouse and cake" are successfully fabricated by using 1H2NA@BA with other luminescence materials. Thus, this study demonstrates fast PAD‐URTP materials with dynamic color‐changing luminescence and opens up new possibilities as the photo‐responsive luminescent material for further mechanistic understanding and future application. [ABSTRACT FROM AUTHOR]

Organic radical luminescent materials have attracted worldwide attention because of their absolute spin‐allowed radiative transition and sensitivity to the environment, which give it multiple stimulus response properties. Nowadays, how to regulate and utilize the sensitivity of radicals has become a hot and difficult issue. Here, arylphosphonium bromide salts are introduced into the molecular backbone of naphthimide (NMI) using an intramolecular counterion strategy, and prepared a novel multifunctional stabilized radical luminescent: TPP‐o‐3OMe‐NMI‐Br. Interestingly, this molecule exhibits different assembly modes in different solvents, resulting in the generation of two crystals with different fluorescence (green: G‐C; orange–yellow: Y‐C), in which the Y‐C crystalline powder exhibits excellent stabilization properties for doublet and triplet excitons, which induce the emission of orange–yellow radical afterglow, and exhibits multi‐stimuli responsiveness to external pressure (P), temperature (T) and water (W). Moreover, interesting time‐dependent photoactivated colorful fluorescence and orange–yellow radical afterglow can be observed in TPP‐o‐3OMe‐NMI‐Br@PMMA films with different doping ratios and exhibit multi‐color tunability, multiple stimulus responses, multiple data encryption, and optical information erase/write behavior. This study not only broadens the types and applications of organic radical long afterglow materials but also provides new ideas for designing new organic "chameleon" luminescent materials in the field of smart luminescence materials. [ABSTRACT FROM AUTHOR]

A simple bromine and cyanogen substituents positional isomeric 9‐phenyl‐9H‐carbazole (PhCz) donor–acceptor system (namely p‐NN‐Br and m‐NN‐Br) displays ultralong organic phosphorescence, and exhibits unique dual emission properties (fluorescence and phosphorescence). These molecules are found to display distinct responses toward multiple external stimuli including temperature (T), excitation light intensity (I) and pressure (P), and show multicolor tunable behaviors (including the white light, the Commission Internationale d'Eclairage (CIE) = 0.33, 0.34). The unique stimuli‐triggered proportion between singlet and triplet excitons for p‐NN‐Br and m‐NN‐Br is demonstrated systematically by investigating the photophysical spectrum, scanning electron microscope (SEM) imaging and X‐ray analysis, coupled with theoretical calculations. They reveal that the simultaneous introduction of halogens (Br) and pseudohalogens (CN) to the PhCz skeleton can improve the intermolecular interaction and thermal stability. Single crystal analysis shows that there are many more types of dimers and J‐aggregates, thereby stabilizing the excitation of triplet states. Moreover, these isomers have "latent" fingerprint recognition and anti‐background interference performance, which is expected to provide a new method for fingerprint identification. All in all, this strategy paves the way to a multifunctional platform for the development of multi‐stimuli responsive, multicolor regulation and smart luminescent materials with long‐lived emission at room temperature. [ABSTRACT FROM AUTHOR]