Photoluminescence Behaviors in Self-Assembly Supramolecular Pyridinium Salts

Abstract

The host–guest supramolecular organic salts would be of great interest due to their excellent optical and electronic properties. Herein, we report three supramolecular materials, o-2MAP, m-3MAP, and p-4MAP, composed of 18-crown-6 and pyridine amine salts, which are crystallized in space groups P1̅, P1̅, and P21/n with a pendulum-like structural variation at room temperature. They all show blue photoluminescence with photoluminescence quantum yields (PLQYs) of 26.85, 77.08, and 32.67%, respectively. The experimental and theoretical analyses reveal that PL emission is associated with strong π–π * and n–π* absorption and charge transition, while hydrogen bond nonvalent interactions affect their structures and cause the enhancement of PLQY. Especially, deep-blue PL materials m-3MAP with the highest PLQY have been used as excellent color conversion media to fabricate ultraviolet light-emitting diodes (UV-LEDs) and anticounterfeiting inks for handwriting and transfer-printing. This work caters to a reliable strategy to design novel optical supramolecular materials and extends their applications for PL materials.