InP/ZnS nanocrystals: Coupling NMR and XPS for fine surface and interface description

H. Virieux , M. Le Troedec , A. Cros-Gagneux , Wilfried-Solo Ojo , Fabien Delpech , Hervé Martinez (1) , Céline Nayral (2) , Bruno Chaudret (2)

1 IPREM - Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux
2 LPCNO - Laboratoire de physique et chimie des nano-objets

Advanced 1H, 13C, and 31P solution- and solid-state NMR studies combined with XPS were used to probe, at the molecular scale, the composition (of the core, the shell, and the interface) and the surface chemistry of InP/ZnS core/shell quantum dots prepared via a non-coordinating solvent strategy. The interface between the mismatched InP and ZnS phases is composed of an amorphous mixed oxide phase incorporating InPO x (with x = 3 and predominantly 4), In2O3, and InOy(OH)3-2y (y = 0, 1). Thanks to the analysis of the underlying reaction mechanisms, we demonstrate that the oxidation of the upper part of the InP core is the consequence of oxidative conditions brought by decarboxylative coupling reactions (ketonization). These reactions occur during both the core preparation and the coating process, but according to different mechanisms.

Domaines: Chimie

H. Virieux, M. Le Troedec, A. Cros-Gagneux, Wilfried-Solo Ojo, Fabien Delpech, et al.. InP/ZnS nanocrystals: Coupling NMR and XPS for fine surface and interface description. Journal of the American Chemical Society, 2012, 134 (48), pp.19701-19708. ⟨10.1021/ja307124m⟩. ⟨hal-01499191⟩