Aromatic heterocyclic π-bridge engineering for broad-color tunable and stimuli-responsive pyrene-based AIEgens

Abstract

Full color-tunable materials are attractive for optoelectronic applications. However, conventional molecular design strategies that incorporate phenyl rings for wavelength modulation often encounter the aggregation-caused quenching (ACQ) effect. To address this challenge, a series of pyrene-based compounds (Py-π-CF₃) with aggregation-induced emission (AIE) characteristics were designed with full-color tunability, emitting from blue sky (492 nm) to red (614 nm) in the solid state by varying aromatic heterocyclic π-bridges. The detailed experiment results indicate that the aromatic heterocyclic π-bridges play a crucial role in regulating the emission color and quantum yield in these pyrene-based AIE luminogens (AIEgens). Furthermore, these AIEgens exhibit photochromism via Z–E isomerization. In addition, the pyridine bridge imparts reversible acidochromism behavior to Py-Pd-CF₃ in both solution and the solid state. Taking advantage of these fascinating stimulus-responsive fluorescence properties, the materials have been successfully applied in multi-level fluorescence-based anti-counterfeiting and information encryption.