title: Structure of Colloidal Quantum Dots from Dynamic Nuclear Polarization Surface Enhanced NMR Spectroscopy.
abstract: Understanding the chemistry of colloidal quantum dots (QDs) is primarily hampered by the lack of analytical methods to selectively and discriminately probe the QD core, QD surface and capping ligands. Here, we present a general concept for studying a broad range of QDs such as CdSe, CdTe, InP, PbSe, PbTe, CsPbBr3, etc., capped with both organic and inorganic surface capping ligands, through dynamic nuclear polarization (DNP) surface enhanced NMR spectroscopy. DNP can enhance NMR signals by factors of 10-100, thereby reducing the measurement times by 2-4 orders of magnitude. 1D DNP enhanced spectra acquired in this way are shown to clearly distinguish QD surface atoms from those of the QD core, and environmental effects such as oxidation. Furthermore, 2D NMR correlation experiments, which were previously inconceivable for QD surfaces, are demonstrated to be readily performed with DNP and provide the bonding motifs between the QD surfaces and the capping ligands.
authors.affiliation: Department of Chemistry and Applied Biosciences, ETH Zürich , Vladimir Prelog Weg 1-5, Zürich CH-8093, Switzerland.|Empa-Swiss Federal Laboratories for Materials Science and Technology , Überlandstrasse 129, Dübendorf CH-8600, Switzerland.
authors.forename: Laura
authors.initials: L
authors.lastname: Piveteau
authors.affiliation: Department of Chemistry and Applied Biosciences, ETH Zürich , Vladimir Prelog Weg 1-5, Zürich CH-8093, Switzerland.
authors.forename: Ta-Chung
authors.initials: TC
authors.lastname: Ong
authors.affiliation: Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL) , Lausanne 1015, Switzerland.
authors.forename: Aaron J
authors.initials: AJ
authors.lastname: Rossini
authors.affiliation: Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL) , Lausanne 1015, Switzerland.
authors.forename: Lyndon
authors.initials: L
authors.lastname: Emsley
authors.affiliation: Department of Chemistry and Applied Biosciences, ETH Zürich , Vladimir Prelog Weg 1-5, Zürich CH-8093, Switzerland.
authors.forename: Christophe
authors.initials: C
authors.lastname: Copéret
authors.affiliation: Department of Chemistry and Applied Biosciences, ETH Zürich , Vladimir Prelog Weg 1-5, Zürich CH-8093, Switzerland.|Empa-Swiss Federal Laboratories for Materials Science and Technology , Überlandstrasse 129, Dübendorf CH-8600, Switzerland.
authors.forename: Maksym V
authors.initials: MV
authors.lastname: Kovalenko