Flexible room-temperature-phosphorescence materials based on polymers with low glass-transition temperatures

Flexible room-temperature-phosphorescence (RTP) materials have attracted widespread attention due to their good stretchability, ease of deformation, and fatigue resistance. However, the stabilization of triplet excitons in RTP materials typically requires a crystalline or a rigid polymer matrix, which severely limits their mechanical flexibility at room temperature (300 K). To address this challenge, polymers with a glass-transition temperature (T_g ) below room temperature have emerged as a promising solution, offering a balance between matrix rigidification and efficient phosphorescence. Therefore, this review focuses on the recent development of flexible RTP polymers with low T_g (<300 K). It begins by exploring the fundamental trade-off between mechanical flexibility and long-lived RTP emission. Then, a comprehensive overview of the molecular design principles, processing strategies, and mechanistic insights for RTP materials with long lifetimes and high quantum yields is provided. Finally, the review summarizes the emerging applications of RTP materials in security information, stretchable displays, and wearable sensors, highlighting the transformative potential of these materials for next-generation flexible optoelectronics.