Supramolecular encrypted fluorescent security ink compositions

Fluorescent dyes, ink compositions comprising the dyes, methods and devices for printing the ink compositions, images printed using the ink compositions and methods for authenticating the printed images are provided. The fluorescent dyes are heterorotaxanes that include large macrocyclic rings around fluorophores and are capable of emitting solid-state fluorescence. When the heterorotaxanes are combined with encapsulating agents and competitive binding agents in aqueous solution, the resulting ink composition exhibits a complex, dynamic equilibrium that provides a tunable fluorescence emission spectrum with a non-linear response to the dye concentration.