Structural evolution of pentacene on a Ag(110) surface

Abstract

Structural evolution of pentacene thin films on Ag͑110͒ crystal, during molecular deposition and during a subsequent change of substrate temperature, was investigated in situ by a molecular beam epitaxy low-energy electron diffraction technique. The pentacene molecules exhibit high mobility on the Ag͑110͒ surface at room temperature and the adsorbate shows a structural evolution from disorder in the submonolayer to an ordered structure when it reaches one monolayer. Heating the substrate to 145°C results in no further structural transition. The ordered monolayer structure on Ag͑110͒ has two domains mirrored at the crystal axis of the silver substrate. Molecular mechanics calculations indicate that the pentacene molecules lie flat on the Ag͑110͒ surface, which is in good agreement with the experimental results. The calculation also gives the favorable position; i.e., the orientation of pentacene on the Ag͑110͒.

Electrostatic field effect on molecular structures at metal surfaces

“…The detailed protocol can be found in Ref. [34][35][36]. The Ag(1 1 0) crystal was cleaned by standard sputtering with argon ions for 15 min at the pressure of 5 Â 10 À6 mbar followed by annealing at 350°C for 3 min.…”

Identifying Multiple Configurations of Complex Molecules in Dynamical Processes: Time Resolved Tunneling Spectroscopy and Density Functional Theory Calculation

“…Experiments were performed using an Omicron UHV MBE-LTSTM system with a base pressure below 3:0 Â 10 À10 mbar [17], and all the experiment results were acquired at 80 K. The molecules of ðt-BuÞ 4 -ZnPc and FePc were purchased from Sigma-Aldrich Inc. Molecules were evaporated to an atomically clean Au(111) surface using the same technique as described in a previous study [18]. STM images were taken in a constant-current mode and the I-t spectra were recorded with the feedback loop open.…”

Structural transition of pentacene monolayer on Ga bilayer: From brick-wall structure to herringbone pattern of molecular dimers

“…Pn is a planar organic molecule that consists of five aromatic rings arranged in a linear fashion. When Pn is deposited on Au(1 1 1) [13,14], Ag(1 1 0) [11], Cu(1 1 0) [7][8][9], Cu(1 0 0) [22] and Si(1 1 1)-Agp 3 · p 3 [23], the brick-wall packing of Pn molecules is observed in the monolayer regime. When the highly polar quinone groups are added to the Pn molecules, the packing pattern transforms into the herringbone pattern [22].…”

“…In the 2-D brick-wall patterns, the molecular layer consists of parallel molecular rows, within which the molecules also have the side-by-side alignment, but with a significant shift along the molecular long axis. This is a typical packing pattern for the aromatic molecules without functional groups, identified for example in case of anthracene and Pn deposited on Ag(1 1 0) [10,11], perylene deposited on Au(1 1 1) [12], and Pn deposited on Au(1 1 1) [13,14].…”

“…When brought into contact with the weakly reactive substrates, the flat-lying geometry with aromatic ring parallel to the substrate is preferred [6]. However, a variety of packing patterns have been observed for the two-dimensional alignments of the aromatic molecules on solid surfaces [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Especially, in case of the linear aromatic molecules having the anisotropic shapes, the packing patterns depend strongly on the competition between the inter-molecular and substrate-molecule interactions.…”