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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 28: Poster III

CPP 28.14: Poster

Wednesday, March 20, 2024, 11:30–13:30, Poster C

Dipolar doping of organic semiconductors for photovoltaics — •Patrick Bunk, Hongwon Kim, Albin Cakaj, Alexander Hofmann, and Wolfgang Brütting — Experimental Physics IV, Institute of Physics, University of Augsburg, 86135 Augsburg, Germany

Previous investigations in the field of organic LEDs showed an improvement in device performance through the doping of dipolar materials, which exhibit a buildup of a giant surface potential (GSP)[1]. However, to the best of our knowledge, dipolar doping has not yet been investigated in the context of organic photovoltaics. For this reason, we investigated prototypical small molecular electron acceptor and donor materials doped with 1,3–Bis[2–(4–tert–butylphenyl)–1,3,4–oxadiazo–5–yl]benzene (Oxd–7) in different ratios using Kelvin Probe (KP). Throughout all doped electron acceptor materials, the GSP was completely suppressed. The doped electron donor (29H,31H–phthalocyaninato(2–)–N29,N30,N31,N32)copper(II) (CuPC) showed a partially suppressed GSP. To investigate the different phases of Oxd-7 in the host material, a Kelvin probe force microscope (KPFM) was used. Furthermore, X-ray diffraction (XRD) measurements led to a better understanding of the orientation of the molecules.

[1] Noguchi et al., Adv. Optical Mater. 2022, 10, 2201278, https://doi.org/10.1002/adom.202201278

Keywords: OPV; Dipolar Doping; Organic Semiconductors; GSP; Orientation