Modulation of Excimer Formation and Photoexcitation Behaviour through DNA‐Surfactant‐Dye Supramolecular Assembly

DNA‐based hybrid materials have attracted much attention recently for their biocompatibility, tunable optical, and semiconducting properties. In this study, thin films fabricated using native DNA are modified to accommodate the assembled fluorescent dyes (perylene and 3‐bromoperylene), alongside the systematical evaluation of their photophysical properties and performance. Spectroscopy results reveal successful modulation of the molecular excitonic behaviour, achieve switchable single‐chromophore multi‐color emission in DNA‐surfactant‐dye thin films, with high optical transparency and thermal robustness. The nucleotide base pairs effectively suppress unfavorable intermolecular π–π stacking and aggregation (self‐association) of the chromophores, which prevents intersystem crossing and relaxation associated Rydberg type molecular clusters to form intermolecular excimers in E‐state (532, 513 nm) and Y‐state (489, 483 nm), blocking nonradiative decay. The preeminent emission observed (457, 445 nm) is attributed to the 0–1 band monomer emission. Compared to PMMA‐dye assembly, the thin film derived from DNA‐surfactant‐dye hybrid narrows the FWHM values up to 72%, displayed molarity ratio‐dependent emission color tunability from yellow‐orange (CIE 0.47, 0.34) to green (CIE 0.31, 0.21) and blue (CIE 0.17, 0.23). These findings provide a simple, all‐solution processed strategy for creating thin films using DNA‐surfactant‐dye hybrid materials with tunable optical properties suitable for biocompatible displays and data encryption. This work demonstrates the modulation of molecular excitonic behaviour, achieving switchable multi‐colour emission in DNA‐surfactant‐dye assemblies. These findings suggest a promising, all‐solution processed strategy for creating optical material with tunable optical properties suitable for biocompatible displays and data encryption.