Multicolor Phenylenediamine Carbon Dots for Metal-Ion Detection with Picomolar Sensitivity

Hani Barhum*, Tmiron Alon, Mohammed Attrash, Andrey Machnev, Ivan Shishkin, Pavel Ginzburg

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Carbon dots keep attracting attention in multidisciplinary fields, motivating the development of new compounds. Phenylenediamine C6H4(NH2)2dots are known to exhibit colorful emission, which depends on size, composition, and the functional surface groups, forming those structures. While quite a few fabrication protocols have been developed, the quantum yield of phenylenediamine dots still does not exceed 50% owing to undesired fragment formation during carbonization. Here, we demonstrate that an ethylene glycol-based environment allows obtaining multicolor high-quantum-yield phenylenediamine carbon dots. In particular, a kinetic realization of solvothermal synthesis in acidic environments enhances carbonization reaction yield for meta phenylenediamine compounds and leads to quantum yields, exciting 60%. Reaction yield after the product’s purification approaches 90%. Furthermore, proximity of metal ions (Nd3+, Co3+, La3+) can either enhance or quench the emission, depending on the concentration. Optical monitoring of the solution allows performing an accurate detection of ions at picomolar concentrations. An atomistic model of carbon dots was developed to confirm that the functional surface group positioning within the molecular structure has a major impact on dots’ physicochemical properties. The high performance of new carbon dots paves the way toward their integration in numerous applications, including imaging, sensing, and therapeutics.

Original languageEnglish
Pages (from-to)9919-9931
Number of pages13
JournalACS Applied Nano Materials
Issue number9
StatePublished - 24 Sep 2021


FundersFunder number
Ministry of Science, Technology, and Space of IsraelN79518


    • carbonization
    • fluorescence
    • molecular dynamics (MD)
    • quantum yield (QY)
    • sensing


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