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HL: Fachverband Halbleiterphysik

HL 19: Organic Electronics and Photovoltaics I (joint session CPP/HL)

HL 19.8: Vortrag

Dienstag, 28. März 2023, 11:30–11:45, GÖR 226

Uniaxially Aligned Merocyanine Films by Graphene Nanoribbon Templated Growth — •Philipp Weitkamp, Lukas Böhner, Nora Gildemeister, Dirk Hertel, and Klaus Meerholz — Physikalische Chemie, Universität zu Köln, Deutschland

We herein report the unique and novel approach of achieving a polycrystalline thin film consisting of uniaxially aligned domains by using 7-armchair graphene nanoribbon (7-aGNR) monolayers as van-der-Waals template. For this purpose, a merocyanine dye was evaporated on 7-aGNRs, transferred on quartz glass substrates. The alignment of the formed molecular aggregate along the GNR alignment direction was proven by polarisation dependent absorbance spectroscopy. The J- and H-transition, formed by the dye aggregate, were correlated with distinct axes of the crystal structure. By combining this correlation with polarisation dependent absorbance measurements and X-ray diffraction experiments we elucidated the three-dimensional structure of the formed aggregate thin film. The growth mode of these films was investigated as a function of the applied layer thickness. Atomic force microscopy-based morphology analysis and X-ray diffraction experiments were used to reveal the anisotropic on-surface crystallisation along the 7-aGNR long axes direction. Furthermore, we found that the delocalisation length of the aggregate increases with increasing in-plane order. Finally, we demonstrated that the in-plane alignment leads to an anisotropic charge carrier transport by implementing the templated merocyanine thin film as active layer in a top-gated organic field effect transistor.