TY - JOUR
T1 - Microscopic Hopping Mechanism of an Isolated PTCDA Molecule on a Reactive Ge(001) Surface
AU - Shiota, Tomoya
AU - Mizukami, Wataru
AU - Tochihara, Hiroshi
AU - Yagyu, Kazuma
AU - Suzuki, Takayuki
AU - Aoki, Yuriko
N1 - Funding Information:
This work was supported in part by funds (Grant Nos. 185008 and 177105) from the Central Research Institute of Fukuoka University. W.M. wishes to thank JSPS KAKENHI No. 18K14181. Y.A. also thanks JSPS KAKENHI No. 16KT0059. Calculations were performed using the computational facilities in the Institute of Solid State Physics at the University of Tokyo and in the Research Institute for Information Technology (RIIT) at Kyushu University, Japan.
Publisher Copyright:
© 2020 American Chemical Society.
Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2020/11/12
Y1 - 2020/11/12
N2 - The molecular hopping of a lone 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) molecule adsorbed on a Ge(001) surface is studied by density functional theory calculations and the climbing-image nudged elastic band method, in which the PTCDA molecule moves along a trough between two adjacent Ge dimer rows. We confirm the previously reported stable state (SS) structure and determine the transition state (TS) structure during the hopping. The TS exhibits the following characteristic features: PTCDA is almost flat above the surface and the adsorption energy (-1.69 eV) is mostly due to the van der Waals (vdW) interaction. The hopping rate constant calculated from the Gibbs free energy of activation indicates that PTCDA is unlikely to hop at 500 K but likely to hop at about 700 K. From changes of Ge-O bond distances during the hopping, the mechanism is named an "inchworm/cheetah"-like hopping with concerted dimer flipping. The origin of the adsorption energy changes from the chemical interaction plus the vdW interaction at the SS to the vdW interaction at the TS during the hopping. The present study gives an insight that strongly adsorbed planar molecules with functional groups on reactive semiconductor surfaces are more mobile than expected.
AB - The molecular hopping of a lone 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) molecule adsorbed on a Ge(001) surface is studied by density functional theory calculations and the climbing-image nudged elastic band method, in which the PTCDA molecule moves along a trough between two adjacent Ge dimer rows. We confirm the previously reported stable state (SS) structure and determine the transition state (TS) structure during the hopping. The TS exhibits the following characteristic features: PTCDA is almost flat above the surface and the adsorption energy (-1.69 eV) is mostly due to the van der Waals (vdW) interaction. The hopping rate constant calculated from the Gibbs free energy of activation indicates that PTCDA is unlikely to hop at 500 K but likely to hop at about 700 K. From changes of Ge-O bond distances during the hopping, the mechanism is named an "inchworm/cheetah"-like hopping with concerted dimer flipping. The origin of the adsorption energy changes from the chemical interaction plus the vdW interaction at the SS to the vdW interaction at the TS during the hopping. The present study gives an insight that strongly adsorbed planar molecules with functional groups on reactive semiconductor surfaces are more mobile than expected.
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U2 - 10.1021/acs.jpcc.0c05858
DO - 10.1021/acs.jpcc.0c05858
M3 - Article
AN - SCOPUS:85095830759
SN - 1932-7447
VL - 124
SP - 24704
EP - 24712
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
IS - 45
ER -