Organic long-persistent luminescence (OLPL) materials show important application prospects in bioimaging due to their low biotoxicity and the ability to eliminate the interference of background fluorescence. However, OLPL materials suffer from poor environmental stability and short afterglow times. Herein, by introducing the phosphorescent guest 2, 3-naphthalimide (NAI) into the B₂O₃ (BO) matrix using a solvent-free method in an air atmosphere, an organic–inorganic hybrid material NAI/BO is obtained, exhibiting OLPL lasting for more than 20 h, visible to the naked eye for up to 180 min. Photoluminescence and thermoluminescence spectra reveal that the OLPL originates from pure phosphorescence of NAI, and is induced by inorganic defects generated by oxygen vacancies in BO. The NAI electrons in the excited state can be captured by the defect, then detrapped through the thermal activation process, and eventually returned to the triplet state of NAI, thereby achieving OLPL emission. NAI/BO is successfully applied in vivo imaging stimulated in vitro. In addition, the universality of this strategy is verified by changing the phosphorescent guest molecules, enabling the regulation of OLPL from green to orange–red light. These results provide an important foundation for the design and development of stable OLPL materials and the practical applications in biological imaging.

中文翻译：

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有机-无机杂化材料的小时级和空气稳定有机长持续发光

有机长持续发光 （OLPL） 材料由于其低生物毒性和消除背景荧光干扰的能力，在生物成像中显示出重要的应用前景。然而，OLPL 材料环境稳定性差，余辉时间短。在此，通过在空气气氛中使用无溶剂方法将磷光客体 2,3-萘酰亚胺 （NAI） 引入 B₂O₃ （BO） 基体中，获得了有机-无机杂化材料 NAI/BO，表现出持续超过 20 小时，肉眼可见长达 180 分钟。光致发光和热释光光谱表明，OLPL 源于 NAI 的纯磷光，是由 BO 中氧空位产生的无机缺陷诱导的。处于激发态的 NAI 电子可以被缺陷捕获，然后通过热活化过程被解封，最终返回到 NAI 的三重态，从而实现 OLPL 发射。NAI/BO 成功应用于体外刺激的体内成像。此外，通过改变磷光客体分子来验证这种策略的通用性，使 OLPL 的调节从绿光变为橙红光。这些结果为稳定 OLPL 材料的设计和开发以及在生物成像中的实际应用提供了重要基础。