Efficiently enhancing aqueous fluorescence of diketopyrrolopyrrole-derived dye via facile cucurbit[8]uril inclusion

Highly emissive fluorescent dyes play an essential role in fluorescence imaging technology and fluorescence spectrometry and have been widely applied in biochemical and environmental science. However, due to the insoluble nature of most organic dyes and low luminous efficiency in water, highly emissive aqueous dyes need to be developed. In this work, a one-step supramolecular strategy was designed, which significantly raised aqueous quantum yields from 3.9% to 46.9% utilizing the designed diketopyrrolopyrrole (DPP) derived dye (DPP-BrBP) to bind with cucurbit[8]uril (CB[8]). The conformation of assembly was proved as quaternary pseudorotane and aggregates of assembly were observed as spherical supramolecular nanoparticals. Supramolecular interactions and mechanism of the effective enhancement of fluorescence were well demonstrated. Besides, self-assembly and intramolecular Förster resonance energy transfer of DPP-BrBP were proved and would exhibit brighter fluorescence with higher concentration. This strategy is valuable for development of aqueous optical materials.