University of Oulu

Irene Papagiannouli, Minna Patanen, Valérie Blanchet, John D. Bozek, Manuel de Anda Villa, Marko Huttula, Esko Kokkonen, Emily Lamour, Eric Mevel, Eetu Pelimanni, Antoine Scalabre, Martino Trassinelli, Dario M. Bassani, Anna Lévy, and Jérôme Gaudin (2018) Depth Profiling of the Chemical Composition of Free-Standing Carbon Dots Using X-ray Photoelectron Spectroscopy. The Journal of Physical Chemistry C 2018 122 (26), 14889-1489,7 DOI: 10.1021/acs.jpcc.8b03800

Depth profiling of the chemical composition of free-standing carbon dots using X-ray photoelectron spectroscopy

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Author: Papagiannouli, Irene1; Patanen, Minna2; Blanchet, Valérie1;
Organizations: 1CELIA, University of Bordeaux, CEA, CNRS UMR 5107, 351 Cours de la Libération, F-33400 Talence, France
2Nano and Molecular Systems Research Unit, Faculty of Science, University of Oulu, P.O. Box 3000, FI-90014 Oulu, Finland
3Synchrotron SOLEIL, l’Orme des Merisiers, Saint-Aubin, BP 48, 91192, Gif-sur-Yvette Cedex, France
4Sorbonne Universités, CNRS, UMR 7588, Institut des Nanosciences de Paris, 75252 Paris Cedex 05, France
5Institut des Sciences Moléculaires, University of Bordeaux, CNRS UMR 5255, 351 Cours de la Libération, 33400 Talence, France
Format: article
Version: accepted version
Access: open
Online Access: PDF Full Text (PDF, 1 MB)
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Language: English
Published: American Chemical Society, 2018
Publish Date: 2018-08-09


The chemical and geometrical structure of free-standing carbon dots (Cdots) prepared from the pyrolysis of N-hydroxysuccinimide (NHS) have been characterized using X-ray photoelectron spectroscopy (XPS). An aerodynamic lens system was used to generate a sufficient particle density of monodispersed Cdots for XPS studies at the PLEIADES beamline at the SOLEIL synchrotron facility. Varying the X-ray excitation energy between 315 and 755 eV allows probing of the Cdots from the surface toward their core, owing to the kinetic energy dependence of the photoelectron inelastic mean free path. The C 1s, O 1s, and N 1s core-levels were recorded with high-spectral resolution to identify their main chemical components and branching ratios. While high-resolution transmission electron microscopy (HRTEM) reveals a defective graphitic core, the C 1s spectrum evidence two main peaks similar to those measured from the solid NHS. Their relative abundance as a function of the probing depth is strongly related to the chemical composition of the ligand shell that does not vary substantially over the first 3.4 nm. Combining the depth-resolved XPS and HRTEM studies, it was concluded that the Cdots possess a graphitic core surrounded by a relatively homogeneous shell of at least 3.4 nm thickness with a composition similar to that of the solid NHS.

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Series: The journal of physical chemistry. C
ISSN: 1932-7447
ISSN-E: 1932-7455
ISSN-L: 1932-7447
Volume: 122
Issue: 26
Pages: 14889 - 14897
DOI: 10.1021/acs.jpcc.8b03800
Type of Publication: A1 Journal article – refereed
Field of Science: 114 Physical sciences
116 Chemical sciences
Funding: I.P. J.G., D.M.B., and A.S. are grateful to the ANR (CASTORS project ANR-13-JS04-0002 and ANR-15-JTIC-0001-01) for financial support. M.P. and M.H. acknowledge the Academy of Finland.
Copyright information: © 2018 American Chemical Society.