Identifying short surface ligands on metal phosphide quantum dots.
The control and understanding of the chemical and physical properties of quantum dots (QDs) demands detailed surface characterization. However, probing the immediate interface between the inorganic core and the ligands is still a major challenge. Here we show that using cross-polarization magic angle spinning (MAS) NMR, unprecedented information can be obtained on the surface ligands of Cd3P2 and InP QDs. The resonances of fragments which are usually challenging to detect like methylene or methyl near the surface, can be observed with our approach. Moreover, ligands such as hydroxyl and ethoxide which have so far never been detected at the surface can be unambiguously identified. This NMR approach is versatile, applicable to any phosphides and highly sensitive since it remains effective for identifying quantities as low as a few percent of surface atoms.
LPCNO (Laboratoire de Physique et Chimie des Nano-Objets), Université de Toulouse, INSA, UPS, CNRS, 135, avenue de Rangueil, F-31077 Toulouse, France. fabien.delpech@insa-toulouse.fr celine.nayral@insa-toulouse.fr.
Edwin A
EA
Baquero
LPCNO (Laboratoire de Physique et Chimie des Nano-Objets), Université de Toulouse, INSA, UPS, CNRS, 135, avenue de Rangueil, F-31077 Toulouse, France. fabien.delpech@insa-toulouse.fr celine.nayral@insa-toulouse.fr.
Wilfried-Solo
WS
Ojo
Laboratoire de Chimie de Coordination, UPR-CNRS 8241, 205 route de Narbonne, 31077 Toulouse Cedex, France.
Yannick
Y
Coppel
LPCNO (Laboratoire de Physique et Chimie des Nano-Objets), Université de Toulouse, INSA, UPS, CNRS, 135, avenue de Rangueil, F-31077 Toulouse, France. fabien.delpech@insa-toulouse.fr celine.nayral@insa-toulouse.fr.
Bruno
B
Chaudret
LPCNO (Laboratoire de Physique et Chimie des Nano-Objets), Université de Toulouse, INSA, UPS, CNRS, 135, avenue de Rangueil, F-31077 Toulouse, France. fabien.delpech@insa-toulouse.fr celine.nayral@insa-toulouse.fr.
Bernhard
B
Urbaszek
LPCNO (Laboratoire de Physique et Chimie des Nano-Objets), Université de Toulouse, INSA, UPS, CNRS, 135, avenue de Rangueil, F-31077 Toulouse, France. fabien.delpech@insa-toulouse.fr celine.nayral@insa-toulouse.fr.
Céline
C
Nayral
LPCNO (Laboratoire de Physique et Chimie des Nano-Objets), Université de Toulouse, INSA, UPS, CNRS, 135, avenue de Rangueil, F-31077 Toulouse, France. fabien.delpech@insa-toulouse.fr celine.nayral@insa-toulouse.fr.
Fabien
F
Delpech