Leveraging Cation Exchange in InP Magic-Sized Clusters To Access Coinage Metal Phosphide Nanocrystals

We report the conversion of In₃₇P₂₀ magic-sized clusters (MSCs) via cation exchange at room temperature to obtain doped InP clusters and nanocrystals, as well as Cu_3–xP, Ag_3–xP, and Au_3–xP nanocrystals. Using a combination of spectroscopic and structural characterization, we determine that the InP clusters undergo doping with significant rearrangement of their ligand shells, but only minor changes in their cores when 1 to 5 equiv of coinage metal salt (per cluster) are added. However, when 37 equiv of coinage metal salt are added, the MSCs fully transform both compositionally and structurally into new ultrasmall coinage metal phosphide nanocrystals with complete extrusion of indium, as determined via X-ray photoelectron spectroscopy, X-ray diffraction, and pair distribution function analysis. We further document the use of these doped InP MSCs and ultrasmall coinage metal phosphide nanocrystals for the synthesis of larger doped InP nanocrystals and a variety of coinage metal phosphide nanocrystals in the 3–15 nm size range.