Herein we report the observation of room-temperature phosphorescence from carbon dots (CDs) embedded in a silica gel matrix. The precursors used in the synthesis (malonic acid and ethylene diamine) were chosen to have the surface of the CDs rich in C[double bond, length as m-dash]O and C[double bond, length as m-dash]N functionalities. The CDs in an aqueous dispersion exhibit an intense blue fluorescence and upon incorporation into silica gel demonstrate a green after-glow, which is visible even to the naked eye. The phosphorescence measurements indicated that the life-time of phosphorescence emission is about 1.8 s, under 380 nm excitation, which is the highest magnitude reported for CDs in solid-state matrices. Moreover, the 1931 CIE color parameters corresponding to the phosphorescence emission are in the white gamut region of the chromaticity diagram.

The single-step synthesis of white-light-emitting carbon dots (CDs) through a green, facile and cheap electrochemical route by using graphite rods as the carbon source is reported. Under UV excitation, the aqueous dispersion of as-synthesised CDs exhibit broad-band emission, which covers a significant fraction of the visible spectrum, owing to the heterogeneity in particle size and surface functional groups. The CDs were further explored for their potential as UV-to-visible colour convertors under remote-phosphor technology by capping a λ=365 nm UV light-emitting diode (LED) chip with CD-loaded poly(methyl methacrylate) to obtain the following colour parameters: Commission Internationale de l'Eclairage chromaticity coordinates (0.35, 0.37), colour rendering index (88) and correlated colour temperature (4802 K).

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.

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UV-photoluminescent carbon dots were synthesized through a facile process and were used as fluorophores for the highly selective and sensitive detection of picric acid.