Toward Efficient Toxic-Gas Detectors: Exploring Molecular Interactions of Sarin and Dimethyl Methylphosphonate with Metal-Centered Phthalocyanine Structures

Aldahhak, Hazem; Powroźnik, Paulina; Pander, Piotr; Jakubik, W.; Dias, Fernando B.; Schmidt, Wolf Gero; Gerstmann, Uwe; Krzywiecki, Maciej

doi:10.1021/acs.jpcc.9b11116

Cited by 21 publications

(20 citation statements)

References 77 publications

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“…Then, the total NEXAFS spectrum of the molecular system was obtained from the superposition of the individual spectra offset by the corresponding core-level shifts, calculated within DFT − for each carbon atom (see, e.g. , refs , , , and for further details). For structures with axial symmetry, the XAS cross section (σ XAS ) for an E -field component, tilted by an angle θ with respect to the surface normal, can be accurately calculated by averaging over two orthogonal azimuthal orientations (for an arbitrary angle φ 0 ): In the present case, the 3-fold symmetry of the substrate is broken by the attached molecules.…”

Section: Materials and Methodsmentioning

confidence: 99%

Tetracene Ultrathin Film Growth on Hydrogen-Passivated Silicon

et al. 2020

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Inorganic−organic interfaces are important for enhancing the power conversion efficiency of silicon-based solar cells through singlet exciton fission (SF). We elucidated the structure of the first monolayers of tetracene (Tc), an SF molecule, on hydrogen-passivated Si( 111) ] and hydrogenated amorphous Si (a-Si:H) by combining near-edge X-ray absorption fine structure (NEXAFS) and Xray photoelectron spectroscopy (XPS) experiments with density functional theory (DFT) calculations. For samples grown at or below substrate temperatures of 265 K, the resulting ultrathin Tc films are dominated by almost upright-standing molecules. The molecular arrangement is very similar to the Tc bulk phase, with only a slightly higher average angle between the conjugated molecular plane normal and the surface normal (α) around 77°. Judging from carbon K-edge X-ray absorption spectra, the orientation of the Tc molecules are almost identical when grown on H−Si(111) and a-Si:H substrates as well as for (sub)mono-to several-monolayer coverages. Annealing to room temperature, however, changes the film structure toward a smaller α of about 63°. A detailed DFT-assisted analysis suggests that this structural transition is correlated with a lower packing density and requires a well-chosen amount of thermal energy. Therefore, we attribute the resulting structure to a distinct monolayer configuration that features less inclined, but still well-ordered molecules. The larger overlap with the substrate wave functions makes this arrangement attractive for an optimized interfacial electron transfer in SF-assisted silicon solar cells.

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Section: Materials and Methodsmentioning

confidence: 99%

Tetracene Ultrathin Film Growth on Hydrogen-Passivated Silicon

et al. 2020

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“…They found that gas adsorption causes the electronic structure on the surface and local spin density polarization to change drastically. The above studies indicate that the process of gas adsorption is related to the crystal structure and electronic characteristics of the surface, as well as the electronic structure and molecular orbitals of the adsorbed gas …”

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confidence: 97%

“…The above studies indicate that the process of gas adsorption is related to the crystal structure and electronic characteristics of the surface, as well as the electronic structure and molecular orbitals of the adsorbed gas. 40 We used first-principles calculations to clarify the changes in the electronic structure and the periodicity of the lattice on WO 3 following gas adsorption. In particular, the charge transfer 39 mechanism was investigated using Bader charge analysis.…”

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Microscopic Nature of Gas Adsorption on WO₃ Surfaces: Electron Interaction and Localization

Jiang

Tao

et al. 2020

J. Phys. Chem. Lett.

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Even though WO3 has been used in gas-sensors for many years, little is known about the gas-sensing mechanism. Using first-principles density functional theory and experimental methods, we study the adsorption of CO, H2, NH3, and NO2 on the surface of WO3 (001). The results indicate that the surface undergoes reconstruction after gas adsorption, which inevitably causes the localization of surface electrons and a change of the electric (sensing) signal. Through the analysis of atomic orbital and molecular orbital, the adsorption mechanism can be effectively predicted. The above analysis confirms that the resistance change is only related to the electronic behavior of the surface and the gas. We corrected problems associated with adsorption energy to characterize the adsorption strength of a gas on a surface, and we investigated the effect of the test temperature and test environment on both electronic interaction and the final electric sensing signal.

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“…This principle can be straightforwardly extrapolated for the entire class of strong electron–donor/acceptor toxic analyte molecules like NO 2 , NO, CO 2 , CO, NH 3, and more, and even for lethal agents as dimethyl methylphosphonate (DMMP) and sarin. [ 57 ] We scrutinized light absorption mechanisms in the hybrid AuNP–CT monolayer and found out the sixfold increase in efficiency of the internal optical transition from nondegenerate low‐lying doubly occupied orbitals toward degenerate half‐empty orbital that can be exploited for ultrafast control over the SOMO–LUMO transition and possibly for switching an electronic configuration of SOMO via breaking its degeneracy. As there is only one electron at SOMO, a paramagnetic response from CT complexes can be anticipated.…”

Section: Discussionmentioning

confidence: 99%

Resonant Plasmon‐Enhanced Absorption of Charge Transfer Complexes in a Metal–Organic Monolayer

Krichevsky

Tolbin

Dubinina

et al. 2021

Advanced Optical Materials

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Plasmonic enhancement of absorption in charge‐transfer (CT) complexes formed under NO2 gas adsorption onto 2D hybrid structure, based on the metal–organic monolayer and gold nanoparticles (AuNPs), is demonstrated. By using Langmuir–Blodgett deposition of low‐symmetry zinc phthalocyanine (ZnPc) molecules, the metal–organic monolayer is fabricated with greatly suppressed intermolecular aggregation. Oxidation of the monolayer through coordination of NO2 molecules with axial zinc ions of ZnPc molecules gives rise to the specific absorption band inherited to cation radical ZnPc+. The hybrid AuNPs–ZnPc structure is engineered to maximize exciton–plasmon interaction of CT complexes at the radical form of the metal–organic monolayer. Excellent spectral and spatial overlaps with plasmon resonance boost absorption of CT internal optical transition, so‐called “fingerprint” band, by a factor of six from 0.45% to 2.8% in total. The approach paves the way for efficient plasmonic control over photochemical reactions promoted by charge‐transfer complexes in metal–organic films. In particular, the plasmonic effect is harnessed to improve NO2 gas sensing properties; the experimental study shows a 15‐fold increase of the detection efficiency in the specific band of CT complexes under the gas exposure.

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Toward Efficient Toxic-Gas Detectors: Exploring Molecular Interactions of Sarin and Dimethyl Methylphosphonate with Metal-Centered Phthalocyanine Structures

Cited by 21 publications

References 77 publications

Tetracene Ultrathin Film Growth on Hydrogen-Passivated Silicon

Tetracene Ultrathin Film Growth on Hydrogen-Passivated Silicon

Microscopic Nature of Gas Adsorption on WO₃ Surfaces: Electron Interaction and Localization

Resonant Plasmon‐Enhanced Absorption of Charge Transfer Complexes in a Metal–Organic Monolayer

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Toward Efficient Toxic-Gas Detectors: Exploring Molecular Interactions of Sarin and Dimethyl Methylphosphonate with Metal-Centered Phthalocyanine Structures

Cited by 21 publications

References 77 publications

Tetracene Ultrathin Film Growth on Hydrogen-Passivated Silicon

Tetracene Ultrathin Film Growth on Hydrogen-Passivated Silicon

Microscopic Nature of Gas Adsorption on WO3 Surfaces: Electron Interaction and Localization

Resonant Plasmon‐Enhanced Absorption of Charge Transfer Complexes in a Metal–Organic Monolayer

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Product

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Microscopic Nature of Gas Adsorption on WO₃ Surfaces: Electron Interaction and Localization