CdSe nanocrystals: controlled growth and diameter-dependent photoluminescence

Phosphonic and carboxylic acids were used as capping agents to fabricate CdSe nanocrystals (NCs) through organic synthesis, leading to a controlled growth of the NCs with adjustable morphologies from dots to rods. The binding energies and steric hindrance of ligands dramatically affected the growth kinetics of CdSe NCs, and therefore the resulting geometry of NCs. The detailed investigations of ligand effect on the growth of NCs and an efficient control over the NCs morphology were presented. CdSe nanorods (NRs) with various aspect ratios were created for studying relation between the diameter of NRs and photoluminescence (PL). Consequently, a synergic use of PL spectra and transmission electron microscopy images allowed us to systematically investigate the relationship between morphology and PL properties of as-prepared CdSe rods. The PL properties of CdSe NRs were finally found to be strongly diameter dependent and weakly related to their lengths.