posted on 2023-10-27, 21:20authored byYanni Jie, Yang Gao, Ge Yang, Pei Xi, Fuchun Li, Jingyu Zhang, Dong Wang, Zengbo Fan, Jiang Yan, Penggao Dai, Jiawen Fang
Long-lifetime room-temperature phosphorescence (RTP)
materials
have various applications in many fields due to their long-lived emission
and large signal-to-noise ratio. However, it is not easy to attain
long-lifetime RTP materials owing to the spin-forbidden nature of
triplet exciton transitions. Herein, yellow phosphorescence carbon-dot-based
composites embedded in a MgO matrix (MgCDs) have been developed, and
the lifetimes were up to 1.81 s (more than 11 s to the naked eye)
in a solid state and 254 ms (more than 9 s to the naked eye) in water.
X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier
transform infrared (FTIR), and XPS analyses were performed, and the
structural characterizations indicate that carbon dots (CDs) embedded
in the rigid magnesium oxide matrix restrict the vibration and rotation
of CDs chromophores and suppress nonradiative recombination of triplet
excitons. Further studies unveiled that the barrier effect of the
insoluble MgO matrix on oxygen is likely mainly responsible for the
observed long-lived RTP in water. In addition, the codoping of N,
P, and Mg elements, as well as the carbonization degree, play an important
role in the luminescence properties of MgCDs. Last but not least,
applications in bioimaging, screen printing, anticounterfeiting, and
information protection are also explored. This work offers fresh ideas
for developing ultralong lifetime afterglow materials that can be
applied in versatile applications.