Aminophosphines as Versatile Precursors for the Synthesis of Metal Phosphide Nanocrystals

We have broadened the scope of the amino-phosphine precursor chemistry that has been developed for InP quantum dots to the synthesis of cadmium, zinc, cobalt, and nickel phosphide nanocrystals. The generalized synthetic conditions involve thermolysis of the appropriate MX2 salt with tris-diethylaminophosphine in a long chain primary amine. The resulting Cd3P2 nanocrystals exhibit size tuning effects based on the metal halide reactivity. P-31 NMR studies show that the II-V materials form via the previously described mechanism observed for InP, demonstrating the invariance of this chemistry to the metal valence. We also demonstrate that electrocatalytically active transition metal phosphides, specifically Co2P, CoP, and Ni2P, can be produced using this synthetic method at relatively mild temperatures and in high yields.