TADF-Active Tetrazole Luminophores for Visible-Light Functionalization of Nanoparticles and Surfaces.

Thermally activated delayed fluorescence (TADF) materials have found broad use in technologies spanning displays, bioimaging, and photocatalysis. In parallel, tetrazoles have become powerful "click" reagents for light-activated, bioorthogonal ligations, yet remain unexplored in reagents with delayed emission lifetimes. Here we report the design and synthesis of TADF-active tetrazole luminophores with photochemical reactivity for the rapid functionalization of nanoparticles and surfaces. The combination of electron-rich phenoxazine donors with electron-deficient tetrazole acceptors yields luminophores with bright emission and tunable TADF lifetimes, governed by the 1,3-dipolar cycloaddition partner. Cycloaddition with alkene dipolarophiles affords saturated dihydropyrazoles that undergo photoinduced aerobic aromatization to generate pyrazole products exhibiting pronounced turn-on TADF behavior. Leveraging their charge-transfer character, we also demonstrate a gold surface modified with TADF luminophores, wherein we propose the first example of reversible visible light-induced surface adsorption. Furthermore, we demonstrate the surface functionalization of organic nanoparticles using TADF-active materials. This work introduces a class of functional materials that combine photochemical reactivity with TADF properties, introducing a light-driven platform for surface functionalization using TADF materials.