Li Xingmei, Liu Xingyu, Zhao Yingying, Zheng Jingxia, Chen Lin, Yang Yongzhen, Liu Xuguang
Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024, China.
College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China.
J Colloid Interface Sci. 2025 Dec 15;700(Pt 3):138585. doi: 10.1016/j.jcis.2025.138585. Epub 2025 Jul 29.
Carbon dots (CDs) as afterglow materials have advantages including easily available raw materials, cost effectiveness, low toxicity, facile surface functionalization, and tunable spectra, demonstrating potential applications in anti-counterfeiting, information encryption, optoelectronics, sensing, and bioimaging. However, most current CD-based afterglow materials exhibit either room-temperature phosphorescence (RTP) or thermally activated delayed fluorescence (TADF) emission, with few demonstrating both properties simultaneously. Their short afterglow lifetimes further limit practical applications. Herein, a long-lifetime dual-mode afterglow F, N-CDs@BA composites were prepared by fluorine doping strategy using boron oxide (BO) as the matrix. The TADF emission wavelength of F, N-CDs@BA is 430 nm, the lifetime is 1.21 s, and the afterglow is visible to the naked eye for about 11 s. The RTP emission wavelength is 510 nm, the lifetime is 0.47 s, and the afterglow is visible to the naked eye for about 13 s. Structural and optical characterizations revealed that the afterglow sources of F, N-CDs@BA composites at 430 and 510 nm originate from F, N-CDs and BO matrices, respectively. Comparative analysis of structural and optical properties, combined with density functional theory calculations of electronic bandgap changes, confirmed that fluorine incorporation reduces the band gap and prolong the afterglow lifetime. All F, N-CDs embedded in different matrices exhibit afterglow emission, demonstrating their matrix universality. Finally, F, N-CDs@BA composites show potential application value in graphic anti-counterfeiting.
碳点（CDs）作为余辉材料具有诸多优点，包括原材料易于获取、成本效益高、毒性低、表面功能化简便以及光谱可调谐等，在防伪、信息加密、光电子学、传感和生物成像等领域展现出潜在应用价值。然而，目前大多数基于CD的余辉材料仅表现出室温磷光（RTP）或热激活延迟荧光（TADF）发射，很少有材料能同时具备这两种特性。它们较短的余辉寿命进一步限制了实际应用。在此，通过以氧化硼（BO）为基质的氟掺杂策略制备了长寿命双模式余辉F，N-CDs@BA复合材料。F，N-CDs@BA的TADF发射波长为430 nm，寿命为1.21 s，肉眼可见余辉约11 s。RTP发射波长为510 nm，寿命为0.47 s，肉眼可见余辉约13 s。结构和光学表征表明，F，N-CDs@BA复合材料在430和510 nm处的余辉源分别来自F，N-CDs和BO基质。通过对结构和光学性质的对比分析，结合电子带隙变化的密度泛函理论计算，证实氟的掺入降低了带隙并延长了余辉寿命。所有嵌入不同基质中的F，N-CDs均表现出余辉发射，证明了它们的基质通用性。最后，F，N-CDs@BA复合材料在图形防伪方面显示出潜在的应用价值。
