CoPc adsorption on Cu(111): Origin of the C4 to C2 symmetry reduction

Cuadrado, R.; Cerdá, Jorge I.; Wang, Yongfeng; Ge, Xinlei; Berndt, Richard; Tang, Hao

doi:10.1063/1.3502682

Cited by 60 publications

(72 citation statements)

References 44 publications

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“…It should be noted that the linear central depression of the TiOPc-dep molecule on the Cu(100) surface (Figure 3(c)) also indicates a 2-fold symmetric feature of the TiOPc-dep/Cu(100) system. The observed symmetry reduction could be resulted from the incommensurability of the 4-fold symmetric phthalocyanine and 6-fold symmetric metal surface [30] or the charge redistribution within the Pc ring because of the charge transfer between molecule and the substrate [5,31]. Considering the weak coupling of Pc ring with the substrate for the O-down configuration and the unobservable symmetry reduction for the TiOPc-pro molecule, a stronger molecule-substrate interaction can be suggested for the TiOPc-dep/Cu(100) system and the charge transfer between O atom and the copper surface leads to the charge redistribution within the Pc ring.…”

Section: Resultsmentioning

confidence: 99%

Orientation of molecular interface dipole on metal surface investigated by noncontact atomic force microscopy

et al. 2013

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We investigated the orientations of interface dipole moments of individual non-planar titanyl phthalocyanine (TiOPc) molecules on Cu(111) and Cu(100) substrates using scanning tunneling microscope (STM) and noncontact atomic force microscope (NC-AFM). The dipole moment orientations corresponding to two different configurations of individual TiOPc molecules were determined unambiguously. The correlation between the actual molecular structures and the corresponding STM topographies is proposed based on the sub-molecular resolution imaging and local contact potential difference (LCPD) measurements. Comparing with the pristine substrate, the LCPD shift due to the adsorption of non-planar molecule is dependent on the permanent molecular dipole, the charge transfer between the surface and the molecule, and the molecular configurations. This work would shed light on tailoring interfacial electronic properties and controlling local physical properties via polar molecule adsorption. titanyl phthalocyanine, interface dipole, non-contact atomic force microscopy, scanning tunneling microscopy, Kelvin probe force microscopy Citation:Yuan B K, Chen P C, Zhang J, et al. Orientation of molecular interface dipole on metal surface investigated by noncontact atomic force microscopy. Chin Sci Bull, 2013Bull, , 58: 36303635, doi: 10.1007 Interface dipoles induced by self-assembly of organic molecules on metal surfaces play an important role in controlling the surface and/or interface properties, especially in the modification of work function of the metal substrate and the energy-level alignment of organic semiconductor with the metal Fermi level [1,2]. Interface dipole is strongly influenced by the permanent dipole of the organic molecule and the "bonding" dipole induced by the molecule-metal interaction [3][4][5][6]. To understand the energy-level alignment at the interface and design interfaces with desired properties, atomic level investigations on the molecular structures of organic adsorbates and interfacial electronic structures are highly required and challenging. Metal phthalocyanines (MPcs), together with their derivatives, have attracted great interest over the past years because of their unique optical and electrical properties [7]. Non-planar MPcs, such as titanyl phthalocyanine (TiOPc), tin phthalocyanine (SnPc) [8], vanadyl phthalocyanine (VOPc) [9,10], chloroaluminum phthalocyanine (ClAlPc) [5] and chlorogallium phthalocyanine (GaClPc) [3], may adsorb on metal surface with two opposite molecular orientations, which give rise to different dipole moments ( Figure 1(b)). Different adsorption configurations have significant influence on the functionalities of molecules and surface and/or interface properties. However, the studies on the effects of the non-planar molecular structure and interfacial electronic structure on interface dipole are still limited. It is thus important to investigate the charge redistribution across the molecule and the metal substrate and to determine the orientations of interface dipole mome...

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Section: Resultsmentioning

confidence: 99%

Orientation of molecular interface dipole on metal surface investigated by noncontact atomic force microscopy

et al. 2013

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“…An alternative route is to evaluate the H sa and M λ sa matrices over an ample set of r tip tip positions and use them as data to set up a parametrization scheme that allows us to approximate these matrices on the fly for any r tip . Such an approach has already been implemented for the H sa matrix elements when simulating topographic images under the elastic regime, 46 while extending it to the M λ sa matrices in order to generate IETS maps in a fast way will be the subject of future works.…”

Section: Discussionmentioning

confidence: 99%

Lowest order in inelastic tunneling approximation: Efficient scheme for simulation of inelastic electron tunneling data

2013

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We have developed an efficient and accurate formalism which allows the simulation at the ab initio level of inelastic electron tunneling spectroscopy data under a scanning tunneling microscope setup. It exploits fully the tunneling regime by carrying out the structural optimization and vibrational mode calculations for surface and tip independently. The most relevant interactions in the inelastic current are identified as the inelastic tunneling terms, which are taken into account up to lowest order, while all other inelastic contributions are neglected. As long as the system is under tunneling regime conditions and there is no physisorbed molecule on the surface or tip apex, this lowest order in inelastic tunneling (LOIT) approach reduces drastically the computational cost compared to related approaches while maintaining a good accuracy. Adopting the wide-band limit for both tip and surface further reduces calculation times significantly, and is shown to give similar results to when the full energy dependence of the Green's functions is taken into account. The LOIT is applied to the Cu(111) + CO system probed by a clean and a CO contaminated tip to find good agreement with previous works. Different parameters involved in the calculations such as basis sets, k sampling, tip-sample distance, or temperature, among others, are discussed in detail.

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“…Similarly, SnPc adsorbed on Ag(111) also shows a C 2 symmetry in STM images (Figure 1(b)). Density functional calculations -with or without van der Waals (vdW) interactions -reveal that the atomic positions in the two perpendicular pairs of molecule ligands are different for both CoPc on Cu(111) 61 and SnPc on Ag(111) (Figure 1(c)). Consequently, the interaction and charge transfer between substrate and molecule should be different for the two molecular axes.…”

Section: Copc On Cu(111)mentioning

confidence: 99%

Review Article: Structures of phthalocyanine molecules on surfaces studied by STM

Wang¹,

Wu²,

Berndt³

2012

AIP Advances

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This review mainly focuses on progress recently achieved in the growth of phthalocyanine molecules on single-crystal surfaces of sub-monolayer up to few-monolayer thin films studied by scanning tunneling microscopy in our groups. On metallic surfaces such as Au(111), Ag(111) and Cu(111), molecular superstructures are determined by combining directional intermolecular interactions caused by symmetry reduction, molecule-substrate interactions and indirect long-range interactions due to quantum interference of surface state electrons. On semiconducting TiO2 surface, molecular assembling structures are dictated by the strong molecule-substrate interaction. However, on insulating NaCl film, molecule-molecule interaction dominates over the molecule-NaCl coupling, leading to molecular growth behavior. Knowledge obtained from these studies would help people better understand the physicochemical properties of the phthalocyanine molecules at surfaces so that their new applications could be further explored and uncovered in the future

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CoPc adsorption on Cu(111): Origin of the C4 to C2 symmetry reduction

Cited by 60 publications

References 44 publications

Orientation of molecular interface dipole on metal surface investigated by noncontact atomic force microscopy

Orientation of molecular interface dipole on metal surface investigated by noncontact atomic force microscopy

Lowest order in inelastic tunneling approximation: Efficient scheme for simulation of inelastic electron tunneling data

Review Article: Structures of phthalocyanine molecules on surfaces studied by STM

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