Dresden 2020 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 49: Poster Session II
CPP 49.36: Poster
Tuesday, March 17, 2020, 14:00–16:00, P1A
Influence of morphology on the work function reduction by polyethylenimine — Sujitkumar Bontapalle1,2, •Andreas Opitz2, Raphael Schlesinger2, Seth R. Marder3, Susy Varughese1, and Norbert Koch2,4 — 1Department of Chemical Engineering, Indian Institute of Technology Madras, Chennai, India — 2Department of Physics and IRIS Adlershof, Humboldt-Universität zu Berlin, Berlin, Germany — 3School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics (COPE), Georgia Institute of Technology Atlanta, Atlanta, USA — 4Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin, Germany
Polyethylenimine (PEI) layers are used to reduce the work function of electrode materials and are frequently applied to organic or perovskite opto-electronic devices. Intermixing of PEI from water-based solution with the conductive polymer poly(3,4-ethylenedioxythiophene):polystyrene sulfonate mixture can be avoided by the usage of anhydrous butanol as solvent for PEI. This preserves also the transparency of the polymer mixture. Heating of inhomogeneous PEI films in ultra-high vacuum ensures the removal of residual solvent and the homogeneous coverage. Thus, the work function of PEI film is reduced to about 1.65 eV below the original substrate work function, which gives 2.3 eV as lowest observed value for zinc oxide.