Long-Range Ordered Hierarchical Structure Assisted by the Side-Oligoether Network in Light-Emitting Conjugated Polymer for an Efficient Deep-Blue Organic Laser

Abstract

The supramolecular interaction network between light-emitting conjugated polymer (LCP) chains provides an excellent electronic landscape and optical cavity to stabilize the excited state and enhance emission efficiency for the fabrication of an organic laser. Herein, we originally demonstrated an exceptional deep-blue lasing from uniformly packed nanowires in a robust emissive spherulite of deep-blue LCPs with a flexible oligoether. The supramolecular interactions between flexible side-oligoethers enable polymer chains to self-assemble into crystalline nanowires and attach into a long-range ordered hierarchical structure. Intriguingly, this novel LCP spherulite exhibits an ultrastable and crystalline-enhanced emission, which is enhanced by about 42% over the emission efficiency of pristine spin-coated films. This robust deep-blue emission with an excellent spectral stability is mainly attributed to the suppression of physical defect formation and enhancement of exciton diffusion in these uniformly packed nanowires. More importantly, such a long-range ordered hierarchical structure also provided an excellent optical cavity to realize exciton population inversion for low-threshold (4.22 μJ/cm2) deep-blue lasing behavior. The study indicates that improvement of emission efficiency and stability in a deep-blue conjugated polymer can be achieved in a synergistic way for fabricating a hierarchically ordered superstructure, which will accelerate the future development and application of light-emitting optoelectronic devices.