General synthesis of uniform metal sulfide colloidal particles via autocatalytic surface growth: a self-correcting system.

After decomposition of thiourea (TU) in the presence of various metal cations to form metal sulfide nanoclusters, an autocatalytic reaction between TU and the surface of the as-formed metal sulfide dominates the further growth of these metal sulfide nanoclusters. This autocatalytic surface growth is self-correcting, leading to formation of uniform metal sulfide colloidal particles. The size (from nanometer to micrometer) and shape of the particles are able to be tuned simply by varying the reactant concentration, reaction time, and temperature. More complex anisotropic particles can also be prepared in the autocatalytic surface growth system.