@article{Cui2026, 
author = {Kaixiang Cui and Keyu Xie and Haonan Peng and Liping Ding and Yu Fang},
title = {Multiscale-coupled triple-confinement engineering: Fabrication and applications of high-efficiency long-lifetime room-temperature phosphorescent carbon dots},
year = {2026},
journal = {Nano Research},
volume = {19},
number = {7},
pages = {94908629},
keywords = {room-temperature phosphorescence, carbon dots, structural confinement, synergistic enhancement, phosphorescence resonance energy transfer},
url = {https://www.sciopen.com/article/10.26599/NR.2026.94908629},
doi = {10.26599/NR.2026.94908629},
abstract = {The practical application of carbon dots (CDs) in room-temperature phosphorescence (RTP) is fundamentally constrained by the inherent trade-off between phosphorescence lifetime and quantum yield within conventional single-confinement systems. Herein, we report a multiscale-coupled triple-confinement paradigm that integrates molecular-level covalent locking (C=N bonds), nanoscale silica encapsulation, and matrix-level boron oxide rigidification. This synergistic design decouples the competing requirements of enhanced intersystem crossing (ISC) and suppressed nonradiative decay, enabling nonlinear performance amplification with a synergy index S = 2.4 (> 1). The optimized CD@SiO2@B2O3 composite exhibits an exceptional phosphorescence lifetime of 1119.8 ms and a quantum yield of 25.98%, corresponding to 3.8-fold and 1.7-fold enhancements relative to single-confinement CD@B2O3 (291.4 ms and 15.35%), respectively. Systematic mechanistic investigations confirm that C=N bonds reduce the singlet-triplet energy gap (ΔEST) by 0.14 eV to facilitate ISC, whereas the hybrid matrix suppresses nonradiative decay rate by 77.2% (from 2.90 to 0.66 s−1). This strategy is readily extendable to other systems and exhibits excellent universality. Furthermore, leveraging phosphorescence resonance energy transfer (PRET) with trace amounts (1 wt.%) of fluorescent dyes enables multicolor RTP tunability while preserving hundreds-millisecond lifetimes, overcoming the emission color restriction of traditional RTP CDs. These merits enable applications including time-gated information encryption with second-level temporal resolution, high-contrast fingerprint visualization on multicolor substrates, and warm-white light-emitting diodes (LEDs) free of commercial phosphors. This work establishes a universal design principle for multiscale-coupled confinement, providing a robust platform for next-generation high-performance RTP materials.}
}