Fine control of the growth and optical properties of CdSe quantum dots by varying the amount of stearic acid in a liquid paraffin matrix

Although stearic acid is a widely used amphiphilic compound in hot-matrix syntheses of quantum dots, the effect of its concentration has not been studied in details in order to achieve better control over the nanocrystal growth process. Here we systematically investigate various mixtures of stearic acid and non-coordinating solvent (paraffin) as the matrix for nucleation and growth of CdSe nanocrystals. The smallest nanoparticles with highest particle concentration in the reaction solution are formed at ca. 35 wt.% of stearic acid. This peculiar trend is confirmed with two different ratios of selenium (Se):Cd precursors. Our findings allow precise tuning of nanoparticle sizes and size distribution, particle concentrations and optical properties in this synthesis, which is among the best candidates for industrial applications.