Regensburg 2019 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
CPP: Fachverband Chemische Physik und Polymerphysik
CPP 50: Organic Electronics and Photovoltaics III - Organic Photovoltaics
CPP 50.5: Vortrag
Donnerstag, 4. April 2019, 10:30–10:45, H18
Impact of Structural Defects on the Energy Level Alignment in planar Pentacene-Perfluoropentacene Heterojunctions — •Jan Hagenlocher1, Alexander Hinderhofer1, Satoshi Kera2, and Frank Schreiber1 — 1Universität Tübingen, Tübingen, Germany — 2Institute for Molecular Science, Okazaki, Japan
The majority of today's organic (opto-)electronic devices comprise a number of different organic-semiconductor layers. The functionality of such complex heterostructures depends on the relative alignment of the frontier molecular-orbital energies in the individual layers with respect to those in all others. In this study we investigated the dependence of this energy level alignment on structural defects in an organic-organic heterojunction of perfluoropentacene (PFP)-on-pentacene (PEN) using x-ray scattering, atomic force microscopy and ultraviolet photoelectron spectroscopy. The density of structural defects was varied by changing the growth temperature of the bottom PEN film. A direct relationship between the defect density and the energy level alignment was found, where the binding energies together with a change in the electrostatic potential at the interface vary systematically with the defect density. This indicates that a key factor affecting the energy level alignment is the number of transferred electrons from the substrate to unoccupied gap states in the PFP film. The described gap states originate from the structural defects and can be effectively controlled by adjusting the growth conditions of the organic films.