Regensburg 2016 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 30: Poster: Organic Electronics and Photovoltaics

CPP 30.17: Poster

Dienstag, 8. März 2016, 18:15–21:00, Poster B2

Charge transfer excitions in weakly interacting organic-organic heterostructures — •Paul Beyer¹, Tino Meisel¹, Alexander Generalov², Ana Sofia Anselmo³, and Andreas Opitz¹ — ¹Institut für Physik, Humboldt-Universität zu Berlin, Germany — ²Maxlab, Lund University, Sweden — ³Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Germany

Different relative molecular orientations at organic-organic heterointerfaces dictate the orbital overlap between neighboring molecules, as well as electronic and structural properties, which are crucial for organic electronic devices. In order to access these properties we utilize a multi-technique approach, consisting of I/V measurements, absorption and photoelectron spectroscopy.

As a donor/acceptor combination, we chose two perylene derivatives: diindenoperylene (DIP) and functionalized perylene alkyldiimide with cyano groups (PDIR-CN₂). The usage of different substrates allows us to tune the molecular orientation inside the grown thin films. We investigated different devices with relevant architectures – planar heterojunctions (PHJ) and planar mixed heterojunctions (PM-HJ).

From absorption measurements, we observed blend exclusive features, proving the creation of new charge transfer states, specifically charge transfer excitons. Depending on the molecular orientation and, thus, the interface geometries, we found clear changes in ionization energies compared to the pristine materials, stemming from differences in energy level alignment.