Dresden 2020 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 86: Organic Electronics and Photovoltaics III

CPP 86.2: Talk

Thursday, March 19, 2020, 09:45–10:00, ZEU 260

Single step production of a self-organized, low work function cathode interlayer from polymer blend solution — •Dominique Lungwitz¹, Keli Fabiana Seidel², Andreas Opitz¹, Thomas Krüger³, Jan Behrends³, Seth R. Marder⁴, and Norbert Koch^1,5 — ¹Institut für Physik and IRIS Adlershof, Humboldt Universität zu Berlin, Germany — ²Physics Department, Universidade Tecnológica Federal do Paraná, Brasil — ³Berlin Joint EPR Lab and Institut für Experimentalphysik, Freie Universität Berlin, Germany — ⁴School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics (COPE), Georgia Institute of Technology Atlanta, USA — ⁵Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Germany

Using cathode interlayers for reducing the work function of electrodes in organic electronic devices is a widely studied method. Here, we report a simple procedure to obtain a self-organized interlayer on ITO electrodes from a blend solution of P(NDI2OD-T2) and PEI. Reduced contact resistance and increased polymer conductivity are observed due to vertical phase separation. Fermi level pinning of P(NDI2OD-T2) at PEI covered ITO electrodes leads to the lowest possible electron injection barrier. Furthermore, an increased charge carrier density was measured. Finally, we relate the increase in polymer conductivity to a reduction of interfacial electron trapping and a morphology change. The results show clearly the importance of differentiation between work function reduction upon interfacial layers and conductivity increase upon changes of structural conformation.