Developing metal-free and long lifetime room-temperature phosphorescence (RTP) materials has received tremendous interest due to their numerous potential applications, of which stable triplet-excited state is the core challenge. Here, boron carbon oxynitride (BCNO) dots, emitting stable blue fluorescence and green RTP, are reported for the first time. The obtained BCNO dots exhibit an unexpected ultralong RTP lifetime of 1.57 s, lasting over 8 s to naked eyes. The effective doping of carbon and oxygen elements in boron nitride (BN) actually provides a small energy gap between singlet and triplet states, facilitating the intersystem crossing (ISC) and populating of triplet excitons. The formation of compact cores via crystallization and effective inter-/intra-dot hydrogen bonds further stabilizes the excited triplet states and reduces quenching of RTP by oxygen at room temperature. Based on the water-soluble feature of BCNO dots, a novel advanced security ink is developed toward anti-counterfeiting tag and confidential information encryption. This study extends BCNO dots to rarely exploited phosphorescence fields and also provides a facile strategy to prepare ultralong lifetime metal-free RTP materials.

由于无数的潜在应用，开发无金属且长寿命的室温磷光（RTP）材料引起了极大的兴趣，其中稳定的三重激发态是核心挑战。在此，首次报道了发出稳定的蓝色荧光和绿色RTP的碳氧氮化硼（BCNO）点。所获得的BCNO点表现出意想不到的1.57 s超长RTP寿命，对裸眼持续超过8 s。氮化硼（BN）中碳和氧元素的有效掺杂实际上在单重态和三重态之间提供了一个小的能隙，从而促进了系统间穿越（ISC）和三重态激子的填充。通过结晶和有效的点间/点内氢键形成致密核，进一步稳定了激发的三线态，并减少了室温下氧对RTP的猝灭。基于BCNO点的水溶性特征，开发了一种新型的高级防伪油墨，用于防伪标签和机密信息加密。这项研究将BCNO点扩展到很少利用的磷光场，并且为制备超长寿命的无金属RTP材料提供了简便的策略。