Regensburg 2022 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 32: Poster Tuesday: Adsorption and Catalysis 1
O 32.7: Poster
Dienstag, 6. September 2022, 11:00–13:00, P3
Thickness-dependent energy level alignment of terrylene molecules on WS2 monolayer — •Qiang Wang1, Sifan You3, Björn Kobin2, Patrick Amsalem1, Lifeng Chi3, Stefan Hecht2, and Norbert Koch1 — 1Institut für Physik & IRIS Adlershof Humboldt-Universität zu Berlin, Berlin, Germany — 2Department of Chemistry & IRIS Adlershof Humboldt-Universität zu Berlin, Berlin, Germany — 3Institute of Functional Nano and Soft Materials (FUNSOM) , Soochow University, Suzhou, China
The exceptional large surface ratio makes 2D TMDC notably sensitive to extrinsic modification. In particular, we study the Van der Waals structure of WS2 monolayers modified by the conjugated terrylene molecules. We show the terrylene/WS2 heterostructures exist in different stacking configurations dependent on the layered coverage, revealed by photoemission spectroscopy and scanning tunnelling microscopy (STM). Electronically, the hybrid heterostructures exhibit type-II energy level alignment. It is further determined that the ionization potentials of terrylene, are reduced by 0.54 eV as the molecule switching from flat-lying to standing orientation. The adsorption behaviour is spatially resolved by STM, indicating two different atomic assembles. As determined by photophysical characterization, low energy electron-hole pairs are also populated upon molecule deposition. Meanwhile the external dielectric screening lowers the Rydberg states of WS2. Our findings reveal the vertical 2D heterostructures enable effective tailoring of both electronic and photophysical properties, which can be applied for various optoelectronic devices.