{
  "abstract": "Citric acid–urea carbon dots are widely used fluorophores, but the influence of reaction duration and solvent on their structural and optical evolution remains underexplored. Here, citric acidurea carbon dots were prepared in water and N,N-dimethylformamide at 200 °C with reaction times ranging from 10 min to 72 h, and selected samples were subsequently functionalized with butylamine, hexylamine, or octylamine via carbodiimide-mediated amide coupling. Structural analysis showed that DMF-derived particles were nitrogen-rich and amide-dominated, whereas water-derived particles were more hydrophilic and carboxyl/hydroxyl-rich, with nonmonotonic compositional changes over time. These differences were mirrored in the photoluminescence behavior: DMF-based synthesis produced gradually red-shifted emission, while aqueous synthesis favored blue-shifted emission and higher quantum yields at specific excitation windows. Alkylamine grafting converted surface carboxyl groups into amides, reduced ζ-potential magnitude, and produced chain-length-dependent interfacial activity, lowering the air–water surface tension from about 70 mN·m −1 to approximately 34 mN·m −1 . The results show that solvent choice and reaction time provide a practical route to tune the core composition, surface chemistry, emission properties, and interfacial behavior of citric acid–urea carbon dots.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": null,
  "author_total": 4,
  "authors": [
    {
      "name": "Dániel Fülöp"
    },
    {
      "name": "Adél Sarolta Rácz"
    },
    {
      "name": "Dániel Olasz"
    },
    {
      "name": "Gergő Gyulai"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/bm4r7ddgscxq0.bib",
  "cited_by": 0,
  "doi": "10.26434/chemrxiv.15008099/v1",
  "fulltext_url": null,
  "id": "bm4r7ddgscxq0",
  "issns": [],
  "landing_url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008099/v1",
  "language": null,
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "journal",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "2505|Carbon and Quantum Dots Applications"
    ]
  ],
  "openalex": "W7204857256",
  "pdf_url": "https://chemrxiv.org/doi/pdf/10.26434/chemrxiv.15008099/v1",
  "pmcid": null,
  "pmid": null,
  "published": "2026-08-31",
  "publisher": "American Chemical Society (ACS)",
  "ris": "https://research.draconitic.com/paper/bm4r7ddgscxq0.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:17Z",
      "native_id": "10.26434/chemrxiv.15008099",
      "source": "chemrxiv",
      "url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008099/v1"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "openalex:2505|Carbon and Quantum Dots Applications",
      "subfield": "materials-polymers"
    }
  ],
  "title": "Time- and Synthesis-Solvent-Dependent Luminescence of Citric Acid–Urea Carbon Dots and Their Alkylamine-Tunable Interfacial Activity",
  "title_text": "Time- and Synthesis-Solvent-Dependent Luminescence of Citric Acid–Urea Carbon Dots and Their Alkylamine-Tunable Interfacial Activity",
  "type": "preprint",
  "updated_at": "2026-10-30T12:17:17Z",
  "url": "https://research.draconitic.com/paper/bm4r7ddgscxq0",
  "venue": "ChemRxiv",
  "versions": []
}