Break the paradox: simultaneous recovery of phosphorescence and mechanics for polymeric films

Abstract

Polymeric films with self-healable room temperature phosphorescence (RTP) and mechanical performances are eagerly needed in the wearable and electronic devices. However, it remains a great challenge to simultaneously recover phosphorescence and mechanical properties, due to the improper interaction to quench phosphorescence and inherent conflict between the chain rigidity and flexibility in polymeric films. Herein, we have proposed a chromophore binder between polymer matrix to fabricate RTP films with simultaneous recovery of phosphorescence and mechanics. Cross-linking covalent network has been established, restricting molecular motion of chromophore binders to achieve bright deep blue phosphorescence emissions. Meanwhile, the films exhibited processability, flexibility, stretchability, and self-healing ability. Note that both phosphorescent and mechanical properties could be recovered with efficiency of more than 90% for the films healed in water under room temperature. Theoretical simulation showed that such a decent self-healing capacity could be ascribed to the relatively low energy to form and re-form covalent cross-linkage between chromophore binders and polymer matrix. Accordingly, we have realized an assemble-reassemble process for multi-emission phosphorescence by healing film fragments using different chromophores with boronic acid groups. It is anticipated that such a facile and universal strategy through covalent cross-linkage could provide possibilities for the design of multi-functional optical materials with expanded application fields.