Continuously tunable emission color based on the molecular aggregation of (2Z,2′Z)-2,2′-(1,4-phenylenae)bis(3-(4-(dodecyloxy)phenyl)acrylonitrile)

Abstract

The development of organic solid-state luminescent materials with continuously tunable emission is a topic of interest for both fundamental research and practical applications. A luminescent liquid crystal, (2Z,2′Z)-2,2′-(1,4-phenylenae)bis(3-(4-(dodecyloxy)phenyl)acrylonitrile) (PDPA) is reported, which exhibits a continuously tunable emission color from green to orange at room temperature when cooled from an isotropic liquid at different cooling rates. PDPA self-assembles to a layer structure and/or a helical structure with different pitch length depending on the stacking rate, which influences the conformation coplanarity. The conjugation lengths shorten and the π–π interactions weaken, inducing a photoluminescence spectrum blue-shift from 600 nm to 506 nm; a considerable luminescent shift. Therefore, this material has potential uses in novel optical devices, as its emission profile can be tuned by controlling the molecular aggregation.