Measurement of the Internal Orbital Alignment of Oligothiophene-TiO2 Nanoparticle Hybrids

X-ray photoemission spectroscopy (XPS), ultraviolet photoemission spectroscopy (UPS), and ultraviolet–visible spectroscopy (UV–vis) were used to investigate the electronic structure of the inner-molecule interface in oligothiophene-TiO2 organic molecule/nanoparticle hybrids. In these molecular structures the TiO2 nanoparticles were covalently bonded to the oligothiophene ligands. The discussed experiments utilized electrospray in-vacuum deposition, enabling the in situ characterization of these materials without the presence of significant ambient contamination. A comparison between the electronic structures of the individual molecular components of the hybrid with the assembled material enabled the determination of the orbital line-up at the internal interface of the hybrid molecules. Transmission electron microscopy (TEM) was used to investigate the morphology and size distribution of the nanoparticles. The results showed that the covalent bond causes an interface dipole at the junction between organic ...