Controlled Deposition Number of Organic Molecules Using Quartz Crystal Microbalance Evaluated by Scanning Tunneling Microscopy Single-Molecule-Counting

Inami, Eiichi; Yamaguchi, Masataka; Yamaguchi, Takayuki; Shimasaki, M.; Yamada, Toyo Kazu

doi:10.1021/acs.analchem.8b01118

Cited by 12 publications

(12 citation statements)

References 30 publications

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“…On-surface metalation of metalfree tetraphenylporphyrin (2HTPP) monolayer islands on Au(111) was demonstrated with 3d-metal adsorption at room temperature and liquid nitrogen temperature of 78.5 K in UHV via a home-built low-temperature UHV-STM setup (base pressure <8 × 10 −9 Pa). 51 Our system included an introduction, a preparation, and an STM analytical chamber. They were interconnected for performing sample preparations and their STM characterization without breaking UHV.…”

Section: Methodsmentioning

confidence: 99%

Direct Imaging of Precursor Adcomplex States during Cryogenic-Temperature On-Surface Metalation: Scanning Tunneling Microscopy Study on Porphyrin Array with Fe Adsorption at 78.5 K

et al. 2020

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On-surface metalation of metal-free π-conjugated planar molecules, such as metal-free tetraphenylporphyrin (2HTPP), using 3d transition metals prepared in ultrahigh vacuum (UHV), attracted significant attention as a newly developed bottom-up method to create a building block for 1-nm-size nano devices, one-or two-dimensional nano networks, as a precursor of further on-surface synthesis or a magnetic atom array aligned on a well-ordered molecular template with an extreme low impurity concentration. Experimental and theoretical studies for this type of on-surface metalation via dehydrogenation (e.g., 2HTPP + Fe → H 2 + FeTPP) have been successfully demonstrated by depositing 3d metal atoms on metal-free π-conjugated planar molecular array at 300 K with subsequent annealing of 350−700 K in UHV. Significantly, photoemission spectroscopy study for the on-surface metalation process at cryogenic temperatures suggested a precursor adcomplex state different from the normal metalation state. In this study, we demonstrate that on-surface metalation at cryogenic temperature reduces thermal diffusion of both metal atoms and molecules, which allows gentle adsorption of the 3d metal atoms inside the molecule, providing precursor adcomplex states while preserving the original well-ordering molecular array structure. Using scanning tunneling microscopy (STM) we investigated Fe deposition on a well-ordered metal-free tetraphenylporphyrin (2HTPP) monolayer array islands with an Au(111) substrate temperature maintained at 78.5 K. Through direct STM topographic and spectroscopy imaging supported by density functional theory calculations, we identify three types of TPP appearance: (1) original 2HTPP, (2) 2HTPP with an Fe atom on top (precursor adcomplex "α" state), and (3) 2HTPP with an Fe atom inside (precursor adcomplex "γ" state, where a clear LUMO peak change was observed).

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Section: Methodsmentioning

confidence: 99%

Direct Imaging of Precursor Adcomplex States during Cryogenic-Temperature On-Surface Metalation: Scanning Tunneling Microscopy Study on Porphyrin Array with Fe Adsorption at 78.5 K

et al. 2020

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“…This setup resulted in a sublimation rate of 0.155 nm/min, which we accurately monitored using a quartz crystal microbalance (QCM) with parameters z impedance = 1 and density = 1. 59 In this study, approximately 0.8 nm of TBB precursors, ascertained via QCM analysis, was deposited on both Au(001) and Cu(111) substrates. On the Au(001) substrate, the deposition of this 0.8 nm layer yielded a self-assembled monolayer (SAM) film at 300 K (Figure S2).…”

Section: Home-built Uhv Stm Setupmentioning

confidence: 99%

Growth of Transition-Metal Cobalt Nanoclusters on 2D Covalent Organic Frameworks

Yamada,

Kanazawa,

Fukutani

et al. 2024

J. Phys. Chem. C

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Two-dimensional (2D) covalent organic frameworks (COFs) fabricated through on-surface synthesis were investigated as a honeycomb nanopore template for the growth of 3d-transition-metal nanoclusters (NCs) with a size of 2 nm on a metallic substrate. The evolution of these NCs and their electronic characteristics were studied employing scanning tunneling microscopy/spectroscopy (STM/STS), angle-resolved ultraviolet photoelectron spectroscopy (ARUPS), and X-ray photoelectron spectroscopy (XPS) under an ultrahigh-vacuum (UHV) condition at room temperature. The 2D COFs were synthesized on Cu(111) substrate utilizing 1,3,5-tris(4-bromophenyl)benzene (TBB) precursors, which engendered a honeycomb nanopore array of approximately 2 nm in size. In contrast to the behavior observed in the Co/Cu( 111) system producing triangular-shaped bilayerstacking nanoclusters measuring 10−20 nm, STM imaging of Co/COFs/Cu(111) revealed the growth of Co NCs of approximately 1.5 nm within a single COF nanopore. This growth occurred without forming a monolayer film beneath the COFs, providing direct evidence that the 2D COFs on Cu(111) can effectively entrap Co atoms within the nanopore, giving rise to Co NCs. Spectroscopy measurements, including STS/UPS/XPS, confirmed the different local densities of states for Co NCs and COFs, corroborating the coexistence of Co NCs and COFs on the surface.

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“…The growth of organic films by molecular evaporation and deposition on atomically clean substrates in ultrahigh vacuum (UHV) has been studied intensively in the last decades. − UHV growth has several advantages with respect to chemical growth methods such as drop-casting a molecular solution on the substrate in air. − First, contamination of the film with solvent residue, a common problem with solution-based processes, is excluded in UHV. Second, the formation of well-ordered molecular arrays can be controlled more easily in molecular beam epitaxy under UHV conditions, because of the cleanliness of the substrate and control of deposition rate and substrate temperature.…”

Section: Introductionmentioning

confidence: 99%

“…Since atomically flat and clean (impurity <1%) substrate surfaces are obtained in UHV, new novel molecular nanostructures can be designed using the atomic precise control of the substrate surface crystalline structures. So far, UHV growth of two-dimensional molecular arrays has mainly focused on flat plane π-conjugated organic molecules, such as phthalocyanine (Pc), porphyrin (TPP), pentacene, perylenetracarboxylic dianhydride (PTCDA), and tetracyanoquinodimethane (TCNQ). − These rigid molecules are not deformed or deconstructed during the sublimation and heating to 400–600 K, which allows for controllable sublimation from molecular powders in an aluminum or quartz crucible in UHV. On atomically flat noble metal substrates, such flat, π-conjugated molecules can self-assemble into well-ordered arrays.…”

Section: Introductionmentioning

confidence: 99%

Well-Ordered Monolayer Growth of Crown-Ether Ring Molecules on Cu(111) in Ultra-High Vacuum: An STM, UPS, and DFT Study

et al. 2019

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Crown-ether (CR) ring molecules are known as host molecules for capturing guest species inside the ring. So far CR molecular films have only been grown by drop-casting a CR solution on an inert substrate in air which offers little control over the molecular structure. Here we report the successful growth of a well-ordered CR molecular array on an atomically flat and clean noble metal Cu(111) substrate at 300 K in ultra-high vacuum (UHV), using 4,4′,5,5′-tetrabromodibenzo[18] crown-6 ether (Br-CR). The adsorption, self-assembly, and electronic structures of Br-CR were studied by means of UHV low-temperature scanning tunneling microscopy and spectroscopy, low electron energy diffraction, and angle-resolved ultraviolet photoemission spectroscopy. We found that (1) the Br-CR ring, which is bent both in the crystal and gas phase, flattens upon adsorption on Cu(111). Density functional theory reveals that the two benzene groups of the molecule lie flat on the surface such as to maximize the substrate-molecule interaction. (2) The moderate molecule−substrate interaction allows thermal diffusion of the Br-CR molecules, resulting in the formation of self-assembled monolayer islands with 7 × 4 superstructure. (3) While the deposition of 0.05 ML Br-CR forms multidomain islands with disordered defects, a drastic improvement occurred at 0.25 ML, where only atomically flat single-domain islands were grown. This Br-CR flat ring cavity array could become a template for designing novel two-dimensional arrays of desired guest atoms, ions, or functionalized molecules.

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Controlled Deposition Number of Organic Molecules Using Quartz Crystal Microbalance Evaluated by Scanning Tunneling Microscopy Single-Molecule-Counting

Cited by 12 publications

References 30 publications

Direct Imaging of Precursor Adcomplex States during Cryogenic-Temperature On-Surface Metalation: Scanning Tunneling Microscopy Study on Porphyrin Array with Fe Adsorption at 78.5 K

Direct Imaging of Precursor Adcomplex States during Cryogenic-Temperature On-Surface Metalation: Scanning Tunneling Microscopy Study on Porphyrin Array with Fe Adsorption at 78.5 K

Growth of Transition-Metal Cobalt Nanoclusters on 2D Covalent Organic Frameworks

Well-Ordered Monolayer Growth of Crown-Ether Ring Molecules on Cu(111) in Ultra-High Vacuum: An STM, UPS, and DFT Study

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