Measurement and prediction of the NEXAFS spectra of pyrimidine and purine and the dissociation following the core excitation

Lin, Yi; Lin, Huei R.; Liu, Wei-Lun; Lee, Yuan T.; Tseng, Chien-Ming; Ni, Chi-Kung; Liu, Chen Lin; Tsai, Cheng Cheng; Chen, Jien Lian; Hu, Wei

doi:10.1016/j.cplett.2015.07.033

Cited by 21 publications

(27 citation statements)

References 25 publications

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“…From the C K-edge spectrum of B2PyMPM, two prominent splitting peaks are observed at 285.0 and 285.7 eV, stemming from the unsaturated C 1s → π* transitions. According to the theoretical study of the NEXAFS of pyridine and pyrimidine, 37 − 39 the lower energy peak is attributed to the C=C carbon atoms and the higher energy peak is attributed to the C=N carbon atoms (see Figure 3 e), which are in line with the XPS fitting results. We can also find two dominant peaks in the same region of B3 and B4PyMPM, due to the higher resolution of the NEXAFS as compared to the C 1s XPS spectra.…”

Section: Results and Discussionsupporting

confidence: 79%

Understanding Interface Dipoles at an Electron Transport Material/Electrode Modifier for Organic Electronics

Chen

Liu

Fahlman

2021

ACS Appl. Mater. Interfaces

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Interface dipoles formed at an electrolyte/electrode interface have been widely studied and interpreted using the “double dipole step” model, where the dipole vector is determined by the size and/or range of motion of the charged ions. Some electron transport materials (ETMs) with lone pairs of electrons on heteroatoms exhibit a similar interfacial behavior. However, the origin of the dipoles in such materials has not yet been explored in great depth. Herein, we systematically investigate the influence of the lone pair of electrons on the interface dipole through three pyridine derivatives B2–B4PyMPM. Experiments show that different positions of nitrogen atoms in the three materials give rise to different hydrogen bonds and molecular orientations, thereby affecting the areal density and direction of the lone pair of electrons. The interface dipoles of the three materials predicted by the “double dipole step” model are in good agreement with the ultraviolet photoelectron spectroscopy results both in spin-coated and vacuum-deposited films. These findings help to better understand the ETMs/electrode interfacial behaviors and provide new guidelines for the molecular design of the interlayer.

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Section: Results and Discussionsupporting

confidence: 79%

Understanding Interface Dipoles at an Electron Transport Material/Electrode Modifier for Organic Electronics

Chen

Liu

Fahlman

2021

ACS Appl. Mater. Interfaces

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“…In addition, two peaks at 286 and 288 eV were found in the TEY data on charging/discharging cycles that remained after discharge back to 0.5 V. These two peaks were not observed in the fluorescence yield spectra reflecting the bulk carbon species. We attributed the peak at 286 eV to carbon in the C–N and C–H bonds of 1-ethyl-3-methylimidazolium cations in the electrolyte residue 22 . The peak observed by TEY at 288 eV—likely resulted from interactions between carbon and chloride ligand of chloroaluminate anions and C–Cl bonding on the surface or edges of NG flakes 23 .…”

Section: Resultsmentioning

confidence: 99%

Advanced rechargeable aluminium ion battery with a high-quality natural graphite cathode

et al. 2017

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Recently, interest in aluminium ion batteries with aluminium anodes, graphite cathodes and ionic liquid electrolytes has increased; however, much remains to be done to increase the cathode capacity and to understand details of the anion–graphite intercalation mechanism. Here, an aluminium ion battery cell made using pristine natural graphite flakes achieves a specific capacity of ∼110 mAh g−1 with Coulombic efficiency ∼98%, at a current density of 99 mA g−1 (0.9 C) with clear discharge voltage plateaus (2.25–2.0 V and 1.9–1.5 V). The cell has a capacity of 60 mAh g−1 at 6 C, over 6,000 cycles with Coulombic efficiency ∼ 99%. Raman spectroscopy shows two different intercalation processes involving chloroaluminate anions at the two discharging plateaus, while C–Cl bonding on the surface, or edges of natural graphite, is found using X-ray absorption spectroscopy. Finally, theoretical calculations are employed to investigate the intercalation behaviour of choloraluminate anions in the graphite electrode.

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“…Figure 2a shows the adsorption step-edge normalized N K-edge NEXAFS spectra measured at 90°, 70°, 50° and 30° photon incidence angle with respect to the sample surface. The spectra display two main resonances: a N 1s to π* transition at 398.7 eV 31 and a N 1s to σ* transition at 407.1 eV. 12 Note that the π* resonance is attenuated probably due to intermolecular interactions or interactions with the substrate.…”

Section: Resultsmentioning

confidence: 99%

Electronic Structure of a Self-Assembled Monolayer with Two Surface Anchors: 6-Mercaptopurine on Au(111)

et al. 2018

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The electronic structure of aromatic and aliphatic thiols on Au(111) has been extensively studied in relation to possible applications in molecular electronics. In this work, the effect on the electronic structure of an additional anchor to the S-Au bond using 6-mercaptopurine as a model system has been investigated. Results from X-ray photoelectron spectroscopy, near-edge X-ray absorption fine structure spectroscopy, and density functional theory (DFT) confirm that this molecule adsorbs on Au(111) with S-Au and iminic N-Au bonds. Combined ultraviolet photoelectron spectroscopy and DFT data reveal that formation of the 6MP self-assembled monolayer generates a molecular dipole perpendicular to the surface, with negative charges residing at the metal/monolayer interface and positive charges at the monolayer/vacuum interface, which lowers the substrate work function. Scanning tunneling microscopy shows two surface molecular domains: a well-ordered rectangular lattice where molecules are tilted on average 30° with respect to the substrate and aligned 6MP islands where molecules are standing upright. Finally, we found a new electronic state located at -1.7 eV with respect to the Fermi level that corresponds to a localized π molecular state, while the state corresponding to the N-Au bond is hybridized with Au d electrons and stabilized at much lower energies (-3 eV).

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Measurement and prediction of the NEXAFS spectra of pyrimidine and purine and the dissociation following the core excitation

Cited by 21 publications

References 25 publications

Understanding Interface Dipoles at an Electron Transport Material/Electrode Modifier for Organic Electronics

Understanding Interface Dipoles at an Electron Transport Material/Electrode Modifier for Organic Electronics

Advanced rechargeable aluminium ion battery with a high-quality natural graphite cathode

Electronic Structure of a Self-Assembled Monolayer with Two Surface Anchors: 6-Mercaptopurine on Au(111)

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