Near-infrared circularly polarized organic room temperature phosphorescence based on a chiral host-guest doping strategy

Achieving high-performance circularly polarized organic room temperature phosphorescence (CPRTP) holds significant academic and industrial importance. Herein, a series of near-infrared, color-tunable, and long-lived CPRTP materials have been successfully constructed by doping achiral luminescent guests into chiral crystallizable hosts. Naphthalimide derivatives are chosen as the guest molecules owing to the large conjugation and good structure tunability. (−)-Di-p-toluoyl-l- and (+)-di-p-toluoyl-d-tartaric acid are selected as the host molecules on account of the outstanding chirality and crystallinity. Through doping naphthalimide into tartaric acid derivatives, the resultant materials show the desirable CPRTP with a luminescence dissymmetry factor equal to 1.14 × 10⁻². The host stabilizes and protects triplet excitons generated from the guest and induces the chirality of phosphorescence. Impressively, the doping material is emissive in the near-infrared region of 720 nm, which has hardly been achieved before. By modifying the chemical structure of the guest, the phosphorescent color of doping materials can be well-modulated from green to yellow and red. Moreover, the doping material displays a lifetime of up to 2.14 s. It is highly anticipated that this work will provide a new design strategy for high-performance CPRTP materials.