Aminophosphines: A Double Role in the Synthesis of Colloidal Indium Phosphide Quantum Dots.
Aminophosphines have recently emerged as economical, easy-to-implement precursors for making InP nanocrystals, which stand out as alternative Cd-free quantum dots for optoelectronic applications. Here, we present a complete investigation of the chemical reactions leading to InP formation starting from InCl3 and tris(dialkylamino)phosphines. Using nuclear magnetic resonance (NMR) spectroscopy and single crystal X-ray diffraction, we demonstrate that injection of the aminophosphine in the reaction mixture is followed by a transamination with oleylamine, the solvent of the reaction. In addition, mass spectrometry and NMR indicate that the formation of InP concurs with that of tetra(oleylamino)phosphonium chloride. The chemical yield of the InP formation agrees with this 4 P(+III) → P(-III) + 3 P(+V) disproportionation reaction occurring, since full conversion of the In precursor was only attained for a 4:1 P/In ratio. Hence it underlines the double role of the aminophosphine as both precursor and reducing agent. These new insights will guide further optimization of high quality InP quantum dots and might lead to the extension of synthetic protocols toward other pnictide nanocrystals.
Physics and Chemistry of Nanostructures, Ghent University , Ghent, Belgium.|Center for Nano and Biophotonics, Ghent University , Ghent, Belgium.
Mickael D
MD
Tessier
Physics and Chemistry of Nanostructures, Ghent University , Ghent, Belgium.|Center for Nano and Biophotonics, Ghent University , Ghent, Belgium.
Kim
K
De Nolf
Physics and Chemistry of Nanostructures, Ghent University , Ghent, Belgium.|Center for Nano and Biophotonics, Ghent University , Ghent, Belgium.
Dorian
D
Dupont
NMR and Structural Analysis Unit, Ghent University , Ghent, Belgium.
Davy
D
Sinnaeve
Physics and Chemistry of Nanostructures, Ghent University , Ghent, Belgium.|Center for Nano and Biophotonics, Ghent University , Ghent, Belgium.
Jonathan
J
De Roo
Physics and Chemistry of Nanostructures, Ghent University , Ghent, Belgium.|Center for Nano and Biophotonics, Ghent University , Ghent, Belgium.
Zeger
Z
Hens