In Situ Photoconversion of Multicolor Luminescence and Pure White Light Emission Based on Carbon Dot-Supported Supramolecular Assembly.

Constructing multicolor photoluminescence materials that allow for the integration of suitable external stimuli in order to control luminescence color conversions is a challenging objective. Multicolor luminescent output that is regulated in an in situ photo-controlled manner is not a common phenomenon. Herein, a photoluminescent supramolecular assembly, prepared in two stages, is described that displays in situ photo-tuning broad-spectrum output. Benefiting from the reversible photo-switched constitutional interconversion of diarylethenes, the fluorescence of a guest molecule, styrylpyridinium-modified diarylethene, can be switched on/off by alternating ultraviolet and visible light irradiation. Upon complexation of this guest with a host, cucurbit[8]uril, the fluorescence intensity of the resulting binary supramolecular nanofiber shows a drastic enhancement when compared with that of the free guest, which can also be quenched and recovered reversibly by light irradiation. Significantly, such cationic supramolecular nanofibers also interact with anionic carbon dots to form broad-spectrum output ternary supramolecular assemblies, the fluorescence of which can be changed efficiently from yellow to blue in an in situ photo-controlled manner. Pure white light emission can be realized expediently in the luminescence color-conversion process. The use of light as an external stimulus to regulate fluorescent color conversion provides us with an opportunity to design and construct more advanced anti-counterfeiting materials as well as visual display instruments.