Determination of the electronic energetics of CdTe nanoparticle assemblies on Au electrodes by photoemission, electrochemical, and photocurrent Studies

This work explores the electronic states of CdTe semiconductor nanoparticles (NPs) that are immobilized on a polycrystalline Au film through an organic linker (dithiol). The HOMO and LUMO energies of the CdTe NPs were determined by using photoelectron spectroscopy and cyclic voltammetry. The results from these measurements show that the HOMO energy is independent of the nanoparticle size and is pinned to the Fermi level, whereas the LUMO energy changes systematically with the size of the NP. Studies with different capping ligands imply that the dithiol ligand removes surface states and enhances the optoelectronic properties of the NPs.