Internal Locking and External Anchoring — A Strategy for Constructing Efficient and Ultralong Room‐Temperature Phosphorescence Materials

Abstract Room‐temperature phosphorescence (RTP) polymer‐based materials have attracted widespread attention due to their advantages of the desired flexibility and processability, high thermal stability, and simple synthesis. Nevertheless, the phosphorescent efficiency of these polymer‐based materials is generally low for the rotation and vibration of luminophores. Herein, an “internal locking and external anchoring” strategy is proposed to completely fix luminophores by introducing thiophene carboxylic acid derivatives into polymers. The resulting polymer‐based RTP materials exhibit a high phosphorescence quantum yield of up to 69%, exceeding the currently reported RTP polymers. The interaction between S and adjacent C═O in the carboxyl group acts as an intramolecular conformational lock, while the strong hydrogen bonds between polymers and guest molecules serve as external anchors. The rotational and vibrational motion of the guest molecules is completely constrained by the synergism effect of internal locking and external anchoring. Additionally, conformational locking facilitates spin–orbit coupling and intramolecular charge transfer of guest molecules. As a result, these polymer‐based materials show ultralong pure RTP with ultrahigh phosphorescence efficiency. Their RTP performance can be adjusted by changing aromatic heterocyclic guests. This work presents a novel and universal way for developing highly efficient polymer‐based RTP materials.