Room-temperature phosphorescence (RTP) materials that glow for seconds after the lights go out have become essential tools for anti-counterfeiting, secure information encryption, and advanced lighting technologies. However, developing efficient, long-lasting phosphorescent materials without toxic heavy metals has remained a significant challenge. Now, researchers at Shaanxi Normal University have developed a groundbreaking triple-confinement strategy that dramatically enhances the performance of carbon-based phosphorescent materials, achieving record-breaking lifetimes and opening new possibilities for practical applications.
The research team, led by Professor Liping Ding and Professor Haonan Peng from School of Chemistry and Chemical Engineering at Shaanxi Normal University, has successfully created carbon dots (CDs) with exceptional room-temperature phosphorescence properties through a multiscale-coupled triple confinement engineering approach. Their work was published in Nano Research on May 25, 2026.
"Conventional single-confinement strategies face an inherent trade-off between phosphorescence lifetime and quantum yield," explained Professor Ding. "Our triple-confinement paradigm integrates molecular-level covalent locking, nanoscale silica encapsulation, and matrix-level boron oxide rigidification to simultaneously enhance both properties—a true synergistic effect rather than simple addition."
The optimized composite material, exhibits an extraordinary phosphorescence lifetime of 1,120 ms and a quantum yield of 25.98%. These values represent 3.8-fold and 1.7-fold improvements, respectively, compared to single-confinement systems. The researchers quantified this synergistic enhancement with a synergy index of 2.4, confirming that the combined effect significantly exceeds what individual confinement layers could achieve separately.
Mechanistic investigations revealed that Schiff-base C=N bonds formed between the carbon precursor and silane coupling agent reduce the singlet-triplet energy gap by 0.14 eV, facilitating efficient intersystem crossing from singlet to triplet excited states. Meanwhile, the hybrid SiO 2 -B 2 O 3 matrix suppresses non-radiative decay rates by 77.2%, stabilizing the triplet excitons responsible for long-lasting phosphorescence.
Beyond the impressive fundamental performance, the researchers addressed a critical limitation of conventional RTP carbon dots—their restricted emission colors, typically confined to blue and green regions. By leveraging phosphorescence resonance energy transfer (PRET) with trace amounts (1 wt%) of commercial fluorescent dyes such as Rhodamine B and Rhodamine 6G, they achieved tunable multicolor phosphorescence spanning from green to orange-red.
These optical properties enable sophisticated practical applications. The researchers demonstrated time-gated information encryption with second-level temporal resolution, where hidden messages become visible only at specific time intervals after UV excitation ceases. They also achieved high-contrast fingerprint visualization on multicolored substrates—a significant improvement over conventional fluorescence-based identification that often struggles with background interference.
Additionally, the team fabricated warm-white light-emitting diodes (WLEDs) without incorporating any commercial phosphors—a distinct advantage over conventional systems. By optimizing the ratio of green-emitting and red-emitting carbon dot composites on LED chips, they achieved neutral white light with correlated color temperatures around 4250 K, closely resembling natural daylight.
"This work establishes a robust platform for next-generation RTP materials," said Professor Ding. "The combination of ultralong lifetime, high efficiency, color tunability, and environmental friendliness makes these carbon dots highly attractive for information security, forensic identification, and solid-state lighting applications."
The research was supported by the National Natural Science Foundation of China and the National Key Research and Development Program of China.
D OI Link:
https://doi.org/10.26599/NR.2026.94908629
About Nano Research
Nano Research is a peer-reviewed, open access, international and interdisciplinary research journal, sponsored by Tsinghua University and the Chinese Chemical Society, published by Tsinghua University Press on the platform SciOpen. It publishes original high-quality research and significant review articles on all aspects of nanoscience and nanotechnology, ranging from basic aspects of the science of nanoscale materials to practical applications of such materials. After 18 years of development, it has become one of the most influential academic journals in the nano field. Nano Research has published more than 1,000 papers every year from 2022, with its cumulative count surpassing 8,000 articles. In 2025 InCites Journal Citation Reports, its 2025 IF is 9.4 (8.3, 5 years), and it continues to be the Q1 area among the four subject classifications. Nano Research Award, established by Nano Research together with TUP and Springer Nature in 2013, and Nano Research Young Innovators (NR45) Awards, established by Nano Research in 2018, have become international academic awards with global influence.
Nano Research
Multiscale-coupled triple-confinement engineering: fabrication and applications of high-efficiency long-lifetime room-temperature phosphorescent carbon dots
25-May-2026