Long Life-time Room-temperature Phosphorescence of Carbon Dots in Aluminum Sulfate

Abstract

Herein we report the observation of room-temperature phosphorescence from carbon dots (CDs) embedded in aluminium sulfate. Phosphorescence emission in CDs was achieved by incorporating C=O/C=N functionalities on the carbon dots (CDs) in a single-step reaction. Benzene-1, 3, 5-tricarboxylic acid and formamide were used as precursors, and the resulting CDs in aqueous dispersion show excellent fluorescence in the blue region with quantum yield about 42.7%. On embedding CDs in aluminum sulfate, a green after-glow, with phosphorescence life-time of~876 ms was observed. The 1931 CIE color parameters corresponding to the phosphorescence emission (0.26, 0.36) indicated that the emission is in the white-gamut region of the chromaticity diagram.[a] J.

A Universal Strategy for Activating the Multicolor Room‐Temperature Afterglow of Carbon Dots in a Boric Acid Matrix

“…1.46 s) . On the other hand, by embedding CDs into various matrices, such as polyvinyl alcohol, potash alum, aluminum sulfate, zeolites, silica gel, urea/biuret, and polyurethane, more superior RTP performances have been obtained in these CD‐based materials. These matrices can effectively fix emissive species and prevent the CD triplet states from quenching.…”

“…the average afterglow lifetime was calculated to be 1.6 s, which is far longer than the reported CDs‐based afterglow materials . As presented in Figure c, the FL and afterglow emission peaks of solid‐state a‐CDs/BA are, respectively located at 469 nm and 530 nm under the optimal excitation.…”

“…As shown in Figure a, both of the b‐CDs/BA and c‐CDs/BA composites exhibit blue and bluish‐green RTP, respectively, indicating the feasibility of this method to activate RTP of heteroatom‐free CDs. According to the basic feature of phosphorescence, the energy level of T 1 is always lower than that of S 1 , so CDs with long‐wavelength FL emission are favorable for acquiring longer‐wavelength RTP. On the one hand, heteroatom doping is widely used to regulate the FL emission wavelength of CDs .…”

“…According to the basic feature of phosphorescence, the energy level of T 1 is always lower than that of S 1 , so CDs with long‐wavelength FL emission are favorable for acquiring longer‐wavelength RTP. On the one hand, heteroatom doping is widely used to regulate the FL emission wavelength of CDs . On the other hand, the doped heteroatom, especially N, P, and halogens are favoring the n→π* transition to facilitate the populate of triplet excitons for RTP .…”

Self‐Protective Room‐Temperature Phosphorescence of Fluorine and Nitrogen Codoped Carbon Dots

“…Some CD‐based RTP materials have already been reported. However, the typical methods for obtaining these RTP materials involves embedding CDs into a polymer matrix (e.g., poly(vinyl alcohol), polyurethane, and silica gel), layered double hydroxides, host matrices, two‐component matrices, or similar systems. These matrices are crucial for stabilizing phosphors with regards to the long lifetime triplet state, which can be easily quenched by molecular vibrations, oxygen molecules, and high temperatures .…”