Dual-channel regulation of a single white-light-emitting compound and its application in time-dependent information encryption

Abstract

Dual-channel regulation of single-molecular white-light fluorescence is proposed. It was found that a newly synthesized bis-phenanthroimidazole (PI) compound could show white-light emission based on acid or base induction through multiple non-covalent interactions. Specifically, the addition of H⁺ or OH⁻ to a dimethyl sulfoxide solution of PI compound causes an emission transition from blue light to white light, owing to protonation of the PI compound. The mixing of the different intermediate species can emit fluorescence of various colors, and approach white-light emission. Further, a multipurpose gel composed of polyvinyl alcohol and PI is prepared, which can serve as an information-writing material. It is found that the film shows no color at the beginning when the information is written. However, when water is evaporated onto the film, the information appears gradually. After the film is dried, the information can be erased again. Thus, a time-dependent and water-vapor-driven information-encryption system is developed, which can provide new insights into the design and application of information-encryption materials.