Twist and charge transfer modulation in imidazo[1,2-a]pyridine encapped 1,3,5-triazine towards multifunctional green-emissive DSEgens: applications in TNP sensing, bioimaging, and organic light emitting diodes

Abstract

The global surge in energy demand for artificial lighting has intensified the pursuit of highly efficient organic light-emitting materials. Herein, we report the design and multifunctional evaluation of two novel triazine-based luminogens, ANU-1 and ANU-2, incorporating imidazo[1,2-a]pyridine as an electron-donating scaffold. Strategic modulation of donor–acceptor geometry and molecular distortion enabled ANU-2 to exhibit dual-state emission (DSE) with reasonable photoluminescence quantum yields in both solution and solid states, while ANU-1 displayed strong solution-phase emission but suffered from aggregation-caused quenching (ACQ). Both luminogens demonstrated excellent thermal and photostability, along with responsiveness to external stimuli such as pH and solvent polarity. ANU-1 selectively detected trinitrophenol (TNP) in solution, whereas ANU-2 enabled versatile sensing in both phases, including solid-state detection via filter paper assays. Additionally, both compounds generated reactive oxygen species (ROS) under light exposure, supporting their potential in photodynamic therapy and environmental remediation. Cellular imaging studies revealed effective uptake in HeLa cells, with ANU-2 showing superior cytoplasmic localization and fluorescence intensity. Non-doped OLED devices fabricated using these luminogens as emissive layers exhibited respectable efficiencies (EQE_max of 3.9% for ANU-1 and (EQE_max) of 1.4% for ANU-2) and minimal roll-off. Collectively, this work presents a robust design strategy for multifunctional triazine-based DSE material, advancing their integration into next-generation platforms for optoelectronics, sensing, and bioimaging.