STM investigation of porphyrin isomers on metal substrates

Terui, Toshifumi; Kamikado, Toshiya; Okuno, Yoshishige; Suzuki, Hitoshi; Mashiko, Shinro

doi:10.1016/j.cap.2003.10.018

Cited by 10 publications

(7 citation statements)

References 14 publications

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“…Note in this case that the phenyl rings are situated at the highest contrast because the 2‘,6‘-bis(3,3-dimethyl-1-butyloxy) substituents extend above them (see Figure ). The structures proposed for the A and B islands are similar to the “face-on” , and “edge-on” 16 stacking modes of porphyrin molecules observed in monolayers and the solid state. The nc-AFM contrast can derive from variations in the local electronic structure, the geometric structure, and/or the rigidity within the molecule.…”

supporting

confidence: 62%

The Effect of Molecular Orientation on the Potential of Porphyrin−Metal Contacts

et al. 2007

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The effect of molecular orientation at metal contacts on interface properties was determined by examining the local work function of porphyrin on atomically smooth graphite. The orientation was varied by self-assembly from the vapor phase, and the local potential was quantified by Kelvin force microscopy (scanning surface potential microscopy). When the porphyrin ring is oriented parallel to the substrate, the surface work function is 50 mV less than that of the highly ordered pyrolytic graphite; in contrast, when the porphyrin molecular plane is oriented perpendicular to the substrate, the surface work function is unchanged. The orientation dependence of the surface work function is determined by the geometric relationships between the delocalized charge densities in the molecule and substrate and possible interface bonding. The differences in interface properties with molecular configuration have important design implications to molecular electronic and organic electronic devices.

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confidence: 62%

The Effect of Molecular Orientation on the Potential of Porphyrin−Metal Contacts

et al. 2007

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“…Therefore, porphyrin derivatives adsorbed on surfaces can be regarded as model systems to study their functionality in biological molecules in detail. Numerous studies demonstrate that monolayers or submonolayers of porphyrins tend to arrange themselves in well-defined long range ordered lateral structures. − The combination of both functionality and structure makes them ideal candidates for molecular devices.…”

Section: Introductionmentioning

confidence: 99%

Understanding the Contrast Mechanism in Scanning Tunneling Microscopy (STM) Images of an Intermixed Tetraphenylporphyrin Layer on Ag(111)

et al. 2008

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The appearance of tetraphenylporphyrins in scanning tunneling micrographs depends strongly on the applied bias voltage. Here, we report the observation and identification of certain features in scanning tunneling microscopy (STM) images of intermixed layers of tetraphenylporphyrin (2HTPP) and cobalt-tetraphenylporphyrin (CoTPP) on Ag(111). A significant fraction of an ordered monolayer of commercially available CoTPP appears as "pits" at negative bias voltages around -1 V. The obvious possibility that these pits are missing molecules within the ordered layer could be ruled out by imaging the molecules at reduced bias voltages, at which the contrast of the pits fades, and at positive bias voltages around +1 V, at which the image contrast is inverted. With the investigation of the electronic structure, in particular the density of states (DOS) close to the Fermi level, of CoTPP and 2HTPP layers by means of ultraviolet photoelectron spectroscopy (UPS) and scanning tunneling spectroscopy (STS), the contrast mechanism was clarified. The correlation of the bias dependent contrast with the UPS data enabled us to interpret the "pits" as individual 2HTPP molecules. Additional evidence could be provided by imaging layers of different mixtures of 2HTPP and CoTPP and by high-resolution STM imaging of the features in CoTPP.

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“…A variety of molecular assembly structures, ranging from alkanes, 40,[64][65][66] acids, [67][68][69][70] alcohols, 41,71 bifunctional molecules, [72][73][74] pi-conjugated molecules 75 (i.e. porphyrin [76][77][78][79] and phthalocyanine derivatives [80][81][82][83][84] ) to fullerenes 80,85,86 and biological molecules have been reported. 80,[87][88][89] Recently, with the rapid development of biosensors, assembly of biological molecules like amino acids, 90,91 proteins, [92][93][94] peptides, 95,96 and DNA 97,98 is beginning to be of particular interest due to their potential application in biosensors.…”

Section: Introductionmentioning

confidence: 99%

Interfacial self-assembly of amino acids and peptides: Scanning tunneling microscopy investigation

Liu

Zhang

2011

Nanoscale

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Proteins play important roles in human daily life. To take advantage of the lessons learned from nature, it is essential to investigate the self-assembly of subunits of proteins, i.e., amino acids and polypeptides. Due to its high resolution and versatility of working environment, scanning tunneling microscopy (STM) has become a powerful tool for studying interfacial molecular assembly structures. This review is intended to reflect the progress in studying interfacial self-assembly of amino acids and peptides by STM. In particular, we focus on environment-induced polymorphism, chiral recognition, and coadsorption behavior with molecular templates. These studies would be highly beneficial to research endeavors exploring the mechanism and nanoscale-controlling molecular assemblies of amino acids and polypeptides on surfaces, understanding the origin of life, unravelling the essence of disease at the molecular level and deeming what is necessary for the "bottom-up" nanofabrication of molecular devices and biosensors being constructed with useful properties and desired performance.

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STM investigation of porphyrin isomers on metal substrates

Cited by 10 publications

References 14 publications

The Effect of Molecular Orientation on the Potential of Porphyrin−Metal Contacts

The Effect of Molecular Orientation on the Potential of Porphyrin−Metal Contacts

Understanding the Contrast Mechanism in Scanning Tunneling Microscopy (STM) Images of an Intermixed Tetraphenylporphyrin Layer on Ag(111)

Interfacial self-assembly of amino acids and peptides: Scanning tunneling microscopy investigation

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