Stable Submicron Aggregates of InP/ZnS Nanocrystals

Abstract

High-temperature colloidal synthesis was used to produce InP nanocrystals with a mean diameter of 2 nm covered with a thin ZnS shell and organic ligands ~1 nm in length. The addition of acetonitrile to a toluene solution of these nanoparticles led to the formation of aggregates with a hydrodynamic diameter of 0.2 μm. The aggregates were stable at acetonitrile/toluene ratios from 1/1 to at least 14/1. A close distance between nanocrystals in the aggregates enabled interparticle Förster resonance energy transfer. The addition of an excess of toluene to a solution of these aggregates promoted their disaggregation into individual InP/ZnS nanocrystals.