Organic Chameleon: Fluorescence, Phosphorescence and Radical Afterglow Triple Emission from Naphthylimide Functionalized Triphenylphosphine Derivatives

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. A simple organic small-molecule luminescent material exhibits fluorescence, phosphorescence, and radical afterglow triple emission properties. Interestingly, it also exhibits multiple stimulus responses, full-color tunability, optical information erasure/writing, and multi-level data encryption behavior, which opens a new door for the development of new organic "chameleon" luminescent materials. image