Room temperature phosphorescence (RTP) materials exhibit fascinating optical properties with great potential for various applications in the fields of luminescent displays and information encryption. However, most afterglow materials rely on pre-processing techniques such as molding and inkjet printing, greatly limiting the portability of their applications. In this study, we propose a reversible photoactivated phosphorescent anti-counterfeiting material. A dynamic photo-printable afterglow film that can be naturally erased was developed by doping carbon dots (CDs) of ofloxacin into polylactic acid (PLA). The material exhibits a 15 s yellow-to-green dynamic afterglow, while the lifetime of the material jumps from 2.5 ms to a maximum of 625 ms under continuous UV irradiation for less than 60 s. Characterization results showed that dynamic RTP originated from external oxygen-containing functional groups and internal nitrogen heterocycles with different decay rates within CDs. Further studies suggested that photoactivation properties should be attributed to the highly oxygen permeable but UV responsive structure of PLA. While oxygen in the membrane was excited by UV light, cross-linking occurs between PLA molecules, providing a rigid environment for CDs and limiting the subsequent entry of oxygen, further extending its lifetime. Based on the above advantages, this dynamic afterglow material has been successfully applied in light-emitting displays and optical molecular logic operation unit design.

中文翻译：

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碳点的时间依赖性磷光可实现多维光活化打印和可调分子计算


室温磷光 （RTP） 材料具有迷人的光学特性，在发光显示器和信息加密领域的各种应用中具有巨大潜力。然而，大多数余辉材料依赖于成型和喷墨打印等预处理技术，这极大地限制了其应用的便携性。在这项研究中，我们提出了一种可逆的光活化磷光防伪材料。通过将氧氟沙星的碳点 （CD） 掺杂到聚乳酸 （PLA） 中，开发了一种可自然擦除的动态照片打印余辉膜。该材料表现出 15 秒的黄到绿动态余辉，而在连续紫外线照射不到 60 秒的情况下，材料的寿命从 2.5 毫秒跃升至最大 625 毫秒。表征结果表明，动态 RTP 来源于 CDs 内具有不同衰减速率的外部含氧官能团和内部氮杂环。进一步的研究表明，光活化特性应归因于 PLA 的高透氧但紫外线响应结构。虽然膜中的氧气被紫外线激发，但 PLA 分子之间发生交联，为 CD 提供了刚性环境并限制了氧气的后续进入，进一步延长了其使用寿命。基于上述优点，这种动态余辉材料已成功应用于发光显示器和光学分子逻辑操作单元设计。