Effect of P-Containing Ligands on the Structural and Optical Properties of (CdSe)(n) (n=3, 6, 10) Clusters

摘要

The effect of phosphorus-containing ligands on the structure, energetics and properties of the (CdSe)(n) clusters (n = 3, 6, and 10) with different number of PH3 and PMe3 ligands were studied by using density functional theory calculations. The P atom in the ligand interacts with Cd and forms a strong Cd-P coordination bond. The introduction of ligands does not change the cluster architecture, but leads to considerable changes in Cd-Se bondlength, charge distribution, binding energy, HOMO-LUMO gap and optical absorption. The ligand influence is enhanced with increasing ligand coverage. A blueshift in absorption band was predicted for the clusters with increasing ligands, resulting from the electron donating characteristics of the ligands that hamper electron transition from Se to Cd. As P-containing ligands are often used in the preparation of CdSe nanocrystals, our calculations reveal the influence of ligand-cluster interaction on the cluster geometrical and electronic properties, which would be helpful for the nanocrystal design and synthesis.