A dark-state–dominated photochemical upconversion afterglow via triplet energy transfer relay

作者：Hang Yuan, Kuangshi Sun, Xianlong Su, Donghao Hu, Yanju Luo, Yishuo Sun, Qian Liu, Lijun Chen, Juan Qiao, Ming Xu, Fuyou Li · 发表于：Science Advances · 年份：2025 · DOI：10.1126/sciadv.adt1225 · 被引用次数：8 · 研究领域：Luminescence and Fluorescent Materials、Organic Light-Emitting Diodes Research、Luminescence Properties of Advanced Materials

Photochemical afterglow materials have drawn considerable attention due to their attractive luminescent properties and great application potential. Considering the classical photochemical afterglow materials always exhibit poor luminescence, it is urgent to gain fundamental understanding of the main limiting factors. Here, we identified the existence of a dark-state triplet in the photochemical process, and an overwhelming percentage of ~98.5% was revealed for this non-emissive triplet state. Guided by these observations, we proposed to activate an unprecedented triplet energy transfer relay to simultaneously harness the singlet and triplet energy. Consequently, an upconverted afterglow material was constructed with amazing luminescence performance albeit its moderate fluorescence emission property. The generality of this strategy was evidenced by the adaptation to similar emitters with varied emission wavelengths. The optimized afterglow performance enabled time-gated upconversion bioimaging under ultralow-power excitation. This study not only reveals the energy transfer pathways for photochemical afterglow but also paves the way for rational design of bright upconverted materials with ultralong lifetime.