Articolo in rivista, 2023, ENG, 10.3390/molecules28010072

Nitrogen-Doped Carbon Quantum Dots for Biosensing Applications: The Effect of the Thermal Treatments on Electrochemical and Optical Properties

Ghezzi F.; Donnini R.; Sansonetti A.; Giovanella U.; La Ferla B.; Vercelli B.

1: Istituto per la Scienza e Tecnologia dei Plasmi, CNR-ISTP, Via Cozzi 53, 20125 Milano, Italy 2,6: Istituto di Chimica della Materia Condensata e di Tecnologie per l'Energia, CNR-ICMATE, Via Cozzi 53, 20125 Milano, Italy 3: Istituto di Scienze del Patrimonio Culturale, CNR-ISPC, Via Cozzi 53, 20125 Milano, Italy 4: Istituto di Scienze e Tecnologie Chimiche "Giulio Natta", CNR-SCITEC, Via Alfonso Corti 12, 20133 Milano, Italy 5: Dipartimento di Biotecnologie e di Bioscienze, Università degli Studi di Milano-Bicocca, Piazza della Scienza 2, 20126 Milano, Italy

The knowledge of the ways in which post-synthesis treatments may influence the properties of carbon quantum dots (CDs) is of paramount importance for their employment in biosensors. It enables the definition of the mechanism of sensing, which is essential for the application of the suited design strategy of the device. In the present work, we studied the ways in which post-synthesis thermal treatments influence the optical and electrochemical properties of Nitrogen-doped CDs (N-CDs). Blue-emitting, N-CDs for application in biosensors were synthesized through the hydrothermal route, starting from citric acid and urea as bio-synthesizable and low-cost precursors. The CDs samples were thermally post-treated and then characterized through a combination of spectroscopic, structural, and electrochemical techniques. We observed that the post-synthesis thermal treatments show an oxidative effect on CDs graphitic N-atoms. They cause their partially oxidation with the formation of mixed valence state systems, [CDs]0+, which could be further oxidized into the graphitic N-oxide forms. We also observed that thermal treatments cause the decomposition of the CDs external ammonium ions into ammonia and protons, which protonate their pyridinic N-atoms. Photoluminescence (PL) emission is quenched.

Molecules (Basel, Online) 28 , pp. 72 -1–72 -12

Keywords

nitrogen-doped carbon quantum dots, hydrothermal synthesis, thermal treatment, optical and electrochemical properties

CNR authors

Ghezzi Francesco Mauro, Sansonetti Antonio, Vercelli Barbara, Giovanella Umberto, Donnini Riccardo

CNR institutes

ICMATE – Istituto di Chimica della Materia Condensata e di Tecnologie per l'Energia, ISPC – Istituto di Scienze del Patrimonio Culturale, ISTP – Istituto per la Scienza e Tecnologia dei Plasmi, SCITEC – Istituto di Scienze e Tecnologie Chimiche "Giulio Natta"

ID: 475523

Year: 2023

Type: Articolo in rivista

Creation: 2022-12-22 11:08:52.000

Last update: 2023-07-04 16:32:22.000

External IDs

CNR OAI-PMH: oai:it.cnr:prodotti:475523

DOI: 10.3390/molecules28010072

Scopus: 2-s2.0-85145844471

ISI Web of Science (WOS): 000908706000001