Regensburg 2019 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 37: Poster Session III
CPP 37.46: Poster
Mittwoch, 3. April 2019, 11:00–13:00, Poster B1
Dipolar doping of organic semiconductors to enhance carrier injection — •Alexander Hofmann1, Vivien Wessels1, Simon Züfle2, Stéphane Altazin2, Kohei Shimizu3, Beat Ruhstaller2, Hisao Ishii3, and Wolfgang Brütting1 — 1Institute of Physics, University of Augsburg, 86135 Augsburg, Germany — 2Institute of Computational Physics, ZHAW, 8401 Winterthur, Switzerland — 3Center for Frontier Science, Chiba University, Chiba, 263-8522 Japan
We have investigated the prototypical polar organic system N,N’-Di(1-naphthyl)-N,N’-diphenyl-(1,1’-biphenyl)-4,4’-diamine (NPB) doped with tris-(8-hydroxyquinolate) aluminum (Alq3) in different ratios by various electrical and optical techniques. Throughout all devices and measurements, a maximum of injected charge carriers and current for low to moderate doping ratios is observed. The strong dipole moment of polar organic materials like Alq3, if not oriented perfectly isotropic, will lead to the buildup of a giant surface potential (GSP). It has been shown previously, that depending on polarity and carrier species, injection can be improved or hindered1. By combining electrical2 and optical measurements as well as simulations, we find a complex relation of positive and negative effects on overall device performance that, besides the influence of the GSP on injection and doping on transport, also reveal a change in NPB energy levels provoked by the dipolar surrounding.
[1] Organic Electronics 39, 244-249 (2016) [2] Journal of Applied Physics 122, 115502 (2017)