In Situ Confinement Strategy To Achieve High-Stability Room Temperature Phosphorescent Carbon Dots

Room temperature phosphorescent (RTP) materials show great application potential in fields such as anticounterfeiting, data encryption, sensors, and bioimaging. However, RTP is prone to being quenched by the influence of oxygen atoms due to the particularity of its luminescence mechanism, leading to the difficulty of obtaining RTP materials with long afterglow and high stability. Herein, multicolored carbon dots-RTP composites (CDs-X@BA) were successfully fabricated via a facile in situ confinement strategy using resorcinol as the carbon source. Specifically, resorcinol underwent in situ carbonization and condensation reactions in boric acid (BA) to form CDs, which were then confined in a rigid environment. Interestingly, the synthesized CDs-X@BA exhibit dual emission afterglow of RTP (550 nm) and thermally activated delayed fluorescence (TADF) (470 nm). Of these, RTP is derived from the formed CDs, while TADF is generated from BA. Notably, CDs-X@BA exhibit remarkable stability, even in water and harsh environments. This is attributed to the formed rigid B₂O₃ matrix, which combines with CDs through physical fixation, hydrogen bonds, and covalent bonds (B-C), fully stabilizing the triplet excitons and suppressing nonradiative transitions. Subsequently, CDs-X@BA exhibit highly promising potential in anticounterfeiting and information security. This work provides new insights for developing high-efficiency RTP materials.