Berlin 2024 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 39: Poster: Metal Substrates

O 39.9: Poster

Dienstag, 19. März 2024, 18:00–20:00, Poster D

P2O and P4O on Ag(111): Homogeneous layers, heterostructures, and mixed layers — Ravi Priya, Keda Jin, and •Peter Jakob — Department of Physics, Philipps-Universität Marburg, Germany

A refined structural analysis of 6,13-pentacenequinone (P2O) and 5,7,12,14-pentacenetetrone (P4O) phases on Ag(111) has been conducted using SPA-LEED. In addition, FT-IR absorption spectroscopy and TDS have been employed to characterize the various phases and associated phase transformations. For both species, lateral ordering is governed by orientation-dependent intermolecular interactions including steric hindrance and in particular hydrogen bonding. P2O as well as P4O display characteristic reflexes in LEED, signalling long-range ordering. These patterns are largely retained up to bilayer coverages. When heterolayers are grown, the reflexes of the ordered contact layers are preserved. Layer exchange is found to occur for the 'P4O on P2O' stacking at T > 200K; no such processes are found for the reversed stacking sequence up to the desorption temperatures of second layer P2O. Different ordered P2O-P4O mixed phases have been identified depending on their relative concentrations in the monolayer and their structure determined. In our study different initial layers have been used to create the various P2O-P4O mixed phases: (i) well-defined 'P4O on P2O' heterolayer stacks plus thermal annealing, (ii) co-deposition of P2O and P4O at 83K, followed by annealing, and (iii) incremental increase of P4O concentration within P2O/Ag(111) monolayer by stepwise addition of P4O followed by annealing.

Keywords: Pentacenequinone; Pentacenetetrone; IRAS; SPA-LEED; IDCT