Ultralong lifetime and efficient room temperature phosphorescent carbon dots through multi-confinement structure design

Abstract

Room temperature phosphorescence materials have inspired extensive attention owing to their great potential in optical applications. However, it is hard to achieve a room temperature phosphorescence material with simultaneous long lifetime and high phosphorescence quantum efficiency. Herein, multi-confined carbon dots were designed and fabricated, enabling room temperature phosphorescence material with simultaneous ultralong lifetime, high phosphorescence quantum efficiency, and excellent stability. The multi-confinement by a highly rigid network, stable covalent bonding, and 3D spatial restriction efficiently rigidified the triplet excited states of carbon dots from non-radiative deactivation. The as-designed multi-confined carbon dots exhibit ultralong lifetime of 5.72 s, phosphorescence quantum efficiency of 26.36%, and exceptional stability against strong oxidants, acids and bases, as well as polar solvents. This work provides design principles and a universal strategy to construct metal-free room temperature phosphorescence materials with ultralong lifetime, high phosphorescence quantum efficiency, and high stability for promising applications, especially under harsh conditions.

Green and Near-Infrared Dual-Mode Afterglow of Carbon Dots and Their Applications for Confidential Information Readout

“…In comparison with hydrogen bonds, the stronger covalent bonding fixation is beneficial for extending occurrence of afterglow from solid state to dispersion state, and meanwhile for achieving RTP and TADF dualmode afterglows by appropriately decreasing the energy gap between the singlet state (S 1 ) and triplet state (T 1 ) (ΔE ST ) of CDs [32]. Besides, multiple fixation of triplet states by covalent bonds, hydrogen bonds and physical confinements (e.g., rigid network and nanoscale spaces of matrices) had been confirmed enabling more effectively activating afterglow emissions of CDs [33][34][35]. Inspired by these results, we suppose that NIR-containing dual-mode afterglow emission from CDs could be obtained by taking proper CDs (with potential NIR afterglow property) and a high-efficient manner to fix them.…”

Chitosan-based carbon nanoparticles as a heavy metal indicator and for wastewater treatment

“…1A) conrmed the conclusion of TEM, showing that the diameter of chi-CNPs mainly distributed in the wide range of 60-100 nm, with an average diameter size of 79.06 nm. The size of carbon nanoparticles prepared in this study are larger than the traditional carbon dots (3-10 nm), [42][43][44] which might be due to the fact that chitosan is a natural polymer and contains a variety of hydrolysates in the process of forming chi-CNPs. Besides, a polymer lm was formed on the surface of the chi-CNPs by dissolving chitosan, which increased the particle size (the particle size is 54.84 nm, the polymer lm is 5.82 nm, and the polymer lm accounts for about one-tenth of the total particle size).…”

Tuning Organic Room‐Temperature Phosphorescence through the Confinement Effect of Inorganic Micro/Nanostructures

“…For example, the CD/silica nanocomposite originating from waste biomass RH showed a UOP lifetime of 5.7 s and a high Φ P of 21.3%. [ 89 ] To further enhance the interaction between silica and organic phosphors, heteroatoms or heavy atoms can be introduced into inorganic precursors. For example, the siloxane coupling agent containing N and halogens is used as a precursor.…”

“…Finally, they used the waste biomass RH with rich silicon and carbon as the only precursor to fabricate metal‐free multiconfined CDs within SiO 2 (CDs@SiO 2 ) by constructing an effective multiconfinement effect (MCE) (Figure 17d,e). [ 89 ] Due to the rigid nanostructure of the Si–O network, CDs were isolated from the external quencher. The CD/silica nanocomposites exhibited a UOP lifetime of 5.72 s and an ultrahigh phosphorescence quantum efficiency (21.3%) (Table 3, Entry 11).…”