Regensburg 2025 – scientific programme
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DS: Fachverband Dünne Schichten
DS 1: Thin Film Properties
DS 1.8: Talk
Monday, March 17, 2025, 11:45–12:00, H3
Ultrathin-Film Y6 at Air-Water Interface via the Langmuir-Blodgett Technique for Optoelectronic Application — •Yisak Tsegazab Gerase1, 2 and Martin Presselt1, 2 — 1Institute of Physical Chemistry, Jena, Germany — 2Leibniz Institute of Photonic Technology, Jena, Germany
Supramolecular structures are critical to the optoelectronic properties of films. The Langmuir-Blodgett (LB) technique provides precise molecular assembly, enabling control and homogenization of the morphology of Y6 Langmuir films, which is essential for scalable fabrication and commercial production. Y6, a non-fullerene acceptor, has significantly improved the power conversion efficiency of organic solar cells. We monitored the in-situ formation of Y6 Langmuir films using Brewster angle microscopy, surface pressure isotherms, and fluorescence spectroscopy. Isotherms revealed high packing densities, while compression-expansion cycles showed increased stiffness due to intermolecular rearrangements. BAM images confirmed smooth, well-defined quasi-2D films, and in-situ fluorescence spectroscopy identified the existence of Y6 fluorophore at the air-water interface and with lateral compression growth in supramolecular structure were observed. In agreement with in-situ observations, these well-ordered morphologies were further characterized after deposition on solid supports. Y6 films used in organic thin-film transistors showed a mobility of about 0.007 cm2 /Vs as cast film, comparable to other deposition techniques.
Keywords: isotherm; interface; monolayer; solar cell; morphology