From Theory to Practice: Advanced Nonlinear Optics and Multicolor, Tunable Fluorescence of Acedan Dyes.

Acedan (ADN) and its derivatives are versatile dyes known for their donor-acceptor properties that can be fine-tuned for numerous spectroscopic applications. Currently, they are widely used as fluorescent probes for labeling biomolecules and cellular organelles. This study examines the newly discovered multifunctionality of three ADN chromophores, amplifying their application perspectives. We employ TD-DFT methods to guide, discuss, and support experimental research. Furthermore, by utilizing nonlinear optical (NLO) techniques such as the Maker fringes method to evaluate third harmonic generation (THG) and all-optical switching (optical Kerr effect, OKE), we show that ADN derivatives exhibit remarkable NLO properties. Specifically, in THG experiments, ADN1, ADN2, and ADN3 reveal signals approximately 2.5, 2.0, and 12.0 times stronger, respectively, than the reference material (silica). Additionally, the OKE experiment confirms ADNs' photoinduced birefringence. Examined acedanes can also exhibit polychromatic fluorescence and energy transfer between individual components in two- and three-dye arrangements. Consequently, this comprehensive study offers valuable insights for applications, such as light-emitting diodes, sensors, projectors, and displays.