Thermal Annealing Effects on Long‐lived Fluorenol Room Temperature Phosphorescence for Styrene Detection

Fluorene derivatives have been widely developed in OLEDs because of its efficient fluorescence quantum efficiency, but for which unique rigid biphenyl planar structure and large conjugated system, we hypothesize that they have a great potential for room temperature phosphorescence (RTP) applications, and confirmed this conjecture by subjecting polyvinyl alcohol (PVA) and phosphors to thermal annealing. The cross‐linked structure formed during thermal annealing judiciously modulates the phosphorescence emission characteristics of the fluorenol with the synergistic interaction between PVA and fluorenol. Specifically, the lifetime exhibited a substantial increase from 1352.2 ms to 2874.1 ms, accompanied by a quantum yield augmentation from 4.8% to 11.3%, which substantiate that cross‐linked induced by thermal annealing effectively amplifies the phosphorescent intensity and stability of the phosphors, facilitating ultralong phosphorescent emission at ambient conditions. Furthermore, an effective probe based on this film is developed for its highly sensitive, quantitative and immediate detection of volatile organic compounds. This investigation not only proffers a novel paradigm for the development of advanced RTP materials but also imparts insightful considerations for optimizing the performance of polymers in conjunction with functional materials, encompassing bioimaging, sensing, and optoelectronic devices.