Role of Fatty Acid in Controlling Nucleation and Growth of CdS Nanocrystals in Solution
We report here the role of free fatty acid in the synthesis of CdS nanocrystals following a well-developed colloidal synthetic procedure using cadmium carboxylate as cadmium and elemental sulfur as sulfur precursor. It is found that fatty acid enhances the reactivity of sulfur precursor, which accelerates the rate of both nucleation and growth of CdS nanocrystals. By controlling this reactivity, high-quality CdS nanocrystals are synthesized at reduced temperature (∼150 °C). This well-known colloidal synthetic method is also found to be a biphasic reaction system where sulfur approaches from the gas phase as H2S and “Cd” from the solution phase.