Multicolor B, N-carbon dots: a versatile platform for ratiometric sensing, anti-counterfeiting, and efficient photothermal conversion

Multi-emitting fluorescent carbon dots (M-CDs) synthesized through a one-pot method have garnered significant attention owing to their tunable properties. These M-CDs exhibit excellent optical properties, low toxicity, and potential for photothermal conversion, making them highly intriguing for various applications. This work effectively harnesses the properties of M-CDs by achieving multiple functions with a single material. M-CDs were synthesized using a one-step hot solvent method with amine molecules and subsequently separated into green-emitting G-CDs, yellow-emitting Y-CDs, as well as red-emitting R-CDs via chromatographic separation. The emission wavelengths of these trichromatic CDs red-shifted with an increase in sp2 conjugated domains. This innovative application of tricolor CDs spans detection, information encryption, and photothermal conversion. Notably, G-CDs are a powerful tool for the detection of the hazardous organic substance 2, 4-dinitrophenylhydrazine, for which the limit of detection is 0.72 nM in the concentration range of 0.5-200 μM. Y-CDs proved highly efficient and accurate in multiple message encryption processes. R-CDs achieved photothermal conversion efficiencies of up to 46%, highlighting their potential in tumor thermal ablation. This work highlights the multifunctionality of M-CDs and delivers new insights for applications in different fields.