8 research outputs found

    Energy level alignment of blended organic semiconductors and electrodes at the interface

    No full text
    The energy level alignment of a blended mixture of organic semiconductors is often depicted as having a common vacuum level. However, this is not a universal phenomenon among the vast number of organic semiconductors that currently exist, as in many cases the energy levels align via the Fermi level. In this report, the energy level alignments of the mixtures; poly(9-vinylcarbazole) (PVK) and 2,7-bis(diphenylphosphoryl)-9,9′-spirobifluorene (SPPO13) and poly(3-hexylthiophene-2,5-diyl) (P3HT) and SPPO13, with varying SPPO13 concentrations, are measured. It was found that the blended systems exhibit two different vacuum levels with the dipole between the PVK and SPPO13 increasing with the SPPO13 concentration, whilst the P3HT and SPPO13 vacuum levels only experience a small change. This is attributed to the decreasing electronic screening with increasing SPPO13 concentration. These new observations have an important implication in our understanding of interfacial behaviour for blended systems commonly used in various organic electronic devices

    The All-Seeing Eye of Resonant Auger Electron Spectroscopy : A Study on Aqueous Solution Using Tender X-rays

    No full text
    X-ray absorption and Auger electron spectroscopies are demonstrated to be powerful tools to unravel the electronic structure of solvated ions. In this work for the first time, we use a combination of these methods in the tender X-ray regime. This allowed us to address electronic transitions from deep core levels, to probe environmental effects, specifically in the bulk of the solution since the created energetic Auger electrons possess large mean free paths, and moreover, to obtain dynamical information about the ultrafast delocalization of the core-excited electron. In the considered exemplary aqueous KCl solution, the solvated isoelectronic K+ and Cl- ions exhibit notably different Auger electron spectra as a function of the photon energy. Differences appear due to dipole-forbidden transitions in aqueous K+ whose occurrence, according to the performed ab initio calculations, becomes possible only in the presence of solvent water molecules
    corecore