Mapping Atomic Contact between Pentacene and a Au Surface using Scanning Tunneling Spectroscopy

Song, Young Jae; Lee, Kyuho; Kim, Seong Heon; Choi, Byung-Hee; Yu, Jaejun; Kuk, Young

doi:10.1021/nl904119y

Cited by 13 publications

(12 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Because both species are weakly adsorbed on the surface at a distance larger than 3.2 Å , the effects of registration site (A 3 at a hollow site and B 3 at a top site) is negligible. The observed different electronic characteristics exemplify that a subtle change of the molecular adsorption height (0.13 Å measured and 0.11 Å calculated) effectively modulates the molecular states [24]. Furthermore, we observed that some C molecules (denoted as C H ) have an apparent height higher than the normal C 3 molecules, as revealed in the line profile of Fig.…”

mentioning

confidence: 62%

Cooperative Modulation of Electronic Structures of Aromatic Molecules Coupled to Multiple Metal Contacts

et al. 2013

View full text Add to dashboard Cite

We use cryogenic scanning tunneling microscopy and spectroscopy and density-functional theory calculations to inspect the modulation of electronic states of aromatic molecules. The molecules are selfassembled on a Cu(111) surface forming molecular networks in which the molecules are in different contact configurations, including laterally coupled to different numbers of coordination bonds and vertically adsorbed at different heights above the substrate. We quantitatively analyze the molecular states and find that a delocalized empty molecular state is modulated by these multiple contacts in a cooperative manner: its energy is down shifted by $0:16 eV for each additional lateral contact and by $0:1 eV as the vertical molecule-surface distance is reduced by 0.1 Å in the physisorption regime. We also report that in a moleculemetal-molecule system the bridging metal can mediate the electronic states of the two molecules. DOI: 10.1103/PhysRevLett.110.046802 PACS numbers: 73.20.Hb, 68.37.Ef, 73.63.Rt, 85.65.+h The electronic structure of a molecule is subject to the coupling of the molecule with its environment [1,2]. A thorough understanding of this issue is of great importance in the field of molecular electronics considering that the characteristics of molecular devices are determined by the molecular electronic structures and their contacts [3]. For example, a metal-molecule interface may strongly modify the molecular orbitals, and consequently, molecular conductance [3]. As one of the ultimate goals of molecular electronics is to realize single-molecule devices, wherein single molecules are connected to electrodes, one needs to understand how molecule-electrode coupling affects the molecular electronic structures at the level of individual molecules. Scanning tunneling microscopy and spectroscopy (STM-STS) have been used to address this challenging problem owing to their capability of resolving geometric details of molecule-metal contacts and simultaneously measuring the single-molecule electronic properties. These studies revealed in great detail that the molecular frontier orbitals are modulated when the molecules are coupled to metal atoms or a metal substrate [4][5][6][7][8][9][10][11][12][13][14]. So far, most of these studies focused on molecules coupled to one or at most two metal contacts. In future single-molecule devices, however, the molecules will be mostly connected to multiple electrodes, for example, to source, drain and gate electrodes in a field-effect transistor [15][16][17][18][19][20]. It is highly desirable to study individual molecules that are coupled to multiple metal contacts.In this Letter, we report on a combined study with low-temperature STM-STS and density-functional theory (DFT) of the electronic structures of extended aromatic molecules that are coupled with multiple metal contacts. The molecules are attached laterally to two or three neighboring molecules through metal-ligand coordination bonds and vertically to a metal surface at different distance. These parameters can be se...

show abstract

mentioning

confidence: 62%

Cooperative Modulation of Electronic Structures of Aromatic Molecules Coupled to Multiple Metal Contacts

et al. 2013

View full text Add to dashboard Cite

show abstract

“…18 Recently reported density functional theory (DFT) calculations for the organic semiconductor pentacene on an Au substrate gave similar results, suggesting orbital hybridization between pentacene and Au. 14 Figure 2c shows energy level diagrams for OTAP, OTAN, and Au. The HOMO levels for OTAP and OTAN are 5.53 and 5.34 eV, respectively.…”

Section: Resultsmentioning

confidence: 99%

Electroconductive π-Junction Au Nanoparticles

Kanehara

Takeya

Uemura

et al. 2012

Bulletin of the Chemical Society of Japan

View full text Add to dashboard Cite

The fabrication of printed electronic circuits using solution-based electroconductive materials at low temperature is essential for the realization of modern printed electronics including transistors, photovoltaic cells, and light-emitting devices. Despite the progress in the field of semiconductor solution materials, reliable electrodes are always fabricated by a vacuum deposition process resulting in only partially solution-processed devices. In this paper, we show that planar phthalocyanine-conjugated Au nanoparticles (NPs) significantly improve the interparticle-carrier-transport properties. The deposition of a solution of the Au NPs under ambient conditions results in an electroconductive metallic thin film without further post-treatment. Maximum conductivity reaches >6600 S cm ¹1 and the conductivity remains unchanged for at least 1 year under ambient conditions. The all-solution-processed organic field-effect transistor (OFET) fabricated under ambient conditions exhibits mobility values as high as 2 cm 2 V ¹1 s ¹1, the value of which is comparable to OFET devices having vacuum-deposited Au electrodes.Electrodes are necessary in all types of electric devices such as transistors, photovoltaic cells, and light-emitting devices. These devices are commonly fabricated by employing expensive vacuum deposition processes. A promising alternative that is cheaper and faster for fabricating devices is wet printing using material from specially designed solutions.1 Many examples of solution processes for transistors, 210 photovoltaic cells, 11 and light-emitting devices 12 have been reported. However, in order to achieve high efficiency and reliable devices, vacuum-processed metals and conductive metal oxide electrodes must be used, thereby producing only partially solution-processed devices. To realize the fabrication of allsolution-processed devices, electrodes must be fabricated at relatively low temperatures from a solution, and the resultant electrode must fulfill three requirements: they must have (1) good contacts, i.e., low resistance at the semiconductor electrode interface, (2) high electroconductivity, and (3) high oxidation stability. In this study, we report that the Au nanoparticles (NPs) possessing orbital hybridization between the Au core and relatively large aromatic molecules meet these three requirements, and consequently, produce reliable electrodes that are comparable to vacuum-deposited Au electrodes.For the fabrication of NP-based electrodes under ambient conditions, surface ligands of inorganic NPs must meet two requirements: they must (1) adhere firmly to the NP surface for colloidal stabilization and (2) provide stable and facile carrier transport between NPs. We found that orbital hybridization between ³ orbitals of aromatic molecules and inorganic orbitals of the Au NPs improves the interparticle-carrier transport. The molecular orbital structure of aromatic compounds is altered when the ³-conjugated plane of aromatic compounds closely bonds while parallel to the metal surface, 1315 and thi...

show abstract

“…This indicates that the TiO 2 anatase substrate does not significantly hybridize frontier molecular orbital states of pentacene in this adsorption configuration, in contrast to chemisorption on metallic substrates where significant orbital broadening and charge transfer were observed. [24][25][26] Bader charge analysis 27,28 revealed that pentacene transfers only 0.1 e − to the TiO 2 substrate.…”

Section: (E)mentioning

confidence: 99%

Pentacene/TiO₂Anatase Hybrid Interface Study by Scanning Probe Microscopy and First Principles Calculations

Todorović

Stetsovych

Moreno

et al. 2018

ACS Appl. Mater. Interfaces

View full text Add to dashboard Cite

The understanding and control of the buried interface between functional materials in optoelectronic devices is key to improving device performance. We combined atomic resolution scanning probe microscopy with first-principles calculations to characterize the technologically relevant organic/inorganic interface structure between pentacene molecules and the TiO anatase (101) surface. A multipass atomic force microscopy imaging technique overcomes the technical challenge of imaging simultaneously the corrugated anatase substrate, molecular adsorbates, monolayers, and bilayers at the same level of detail. Submolecular resolution images revealed the orientation of the adsorbates with respect to the substrate and allowed direct insights into interface formation. Pentacene molecules were found to physisorb parallel to the anatase substrate in the first contact layer, passivating the surface and promoting bulk-like growth in further organic layers. While molecular electronic states were not significantly hybridized by the substrate, simulations predicted localized pathways for molecule-surface charge injection. The localized states were associated with the molecular lowest unoccupied molecular orbital inside the oxide conduction band, pointing to efficient transfer of photo-induced electron charge carriers across this interface in prospective photovoltaic devices. In uncovering the atomic arrangement and favorable electronic properties of the pentacene/anatase interface, our findings testify to the maturity and analytic power of our methodology in further studies of organic/inorganic interfaces.

show abstract

Mapping Atomic Contact between Pentacene and a Au Surface using Scanning Tunneling Spectroscopy

Cited by 13 publications

References 25 publications

Cooperative Modulation of Electronic Structures of Aromatic Molecules Coupled to Multiple Metal Contacts

Cooperative Modulation of Electronic Structures of Aromatic Molecules Coupled to Multiple Metal Contacts

Electroconductive π-Junction Au Nanoparticles

Pentacene/TiO₂Anatase Hybrid Interface Study by Scanning Probe Microscopy and First Principles Calculations

Contact Info

Product

Resources

About

Mapping Atomic Contact between Pentacene and a Au Surface using Scanning Tunneling Spectroscopy

Cited by 13 publications

References 25 publications

Cooperative Modulation of Electronic Structures of Aromatic Molecules Coupled to Multiple Metal Contacts

Cooperative Modulation of Electronic Structures of Aromatic Molecules Coupled to Multiple Metal Contacts

Electroconductive π-Junction Au Nanoparticles

Pentacene/TiO2Anatase Hybrid Interface Study by Scanning Probe Microscopy and First Principles Calculations

Contact Info

Product

Resources

About

Pentacene/TiO₂Anatase Hybrid Interface Study by Scanning Probe Microscopy and First Principles Calculations