Synergistic effect of carboxylic and amine ligands on the synthesis of CdSe nanocrystals

We demonstrate the drastic improvement in absorbance and photoluminescence (UV-PL) of CdSe nanocrystals (NCs) upon adding both a carboxylic acid and an amine ligand to the cadmium acetate green chemistry source. We combined carboxylate complexes of lauric acid (LAc), myristic acid (MAc), stearic acid (SAc) and oleic acid (OAc), along with the lewis bases octyl amine (OAm), dodecyl amine (DDAm), hexadecyl amine (HDAm) and octadecyl amine (ODAm) to study their effect on CdSe NCs quality. While single use of either acid or amine ligands does not lead to an advantageous change in CdSe nanocrystal yield and properties, an evident synergistic effect is observed on the CdSe nanocrystals optical properties upon concurrent use of acid and amine ligands. By this, a remarkable improvement in particle quality is achieved, as measured by a sharp and narrow peak of 18 nm (FWHM) in the photoluminescence spectral distribution corresponding to a particle size of 2.2 nm.