Bonding Structures Research Articles

Double hydrogen bonding-induced compact H-type π-π stacking enhancing rapid carrier transfer in perylene diimide supramolecules achieving high oxygen evolution performance

Perylene diimides (PDI) are widely used in photocatalytic oxygen evolution due to their deep valence band potentials. Here, we report the synthesis of a unique supramolecular photocatalyst (designated s-PDI-P1) by introducing hydroxyl and carboxyl groups at the imide position of PDI. This modification allows the formation of intermolecular double hydrogen bond structures between the hydroxyl groups, oxygen atoms on the perylene cores and the carboxyl groups. The resulting double hydrogen bonding structures reduce lateral slip and promote the formation of supramolecular structures with H-type π-π stacking. In addition, the intermolecular hydrogen bonding interactions between the hydroxyl groups and the oxygen atoms on the perylene cores bring the PDI molecules closer together, enhancing the conjugation of the PDI supramolecules and facilitating the formation of ultrathin nanosheet-like structures. In this study, we successfully constructed ultrathin nanosheets of the supramolecular photocatalyst s-PDI-P1 with a compact H-type π-π stacking structure, which exhibited enhanced charge transfer capability, shorter charge migration distance, and achieved a high photocatalytic oxygen evolution rate of 3.23 mmolg-1h−1. These results highlight the potential of intermolecular double hydrogen bond structures to improve the separation and migration driving force of photogenerated charges, thus providing a novel design strategy for organic photocatalysts.

Tetrahedral Bonding Structure (Ni3 -Se) Induced by Lattice-Distortion of Ni to Achieve High Catalytic Activity in Na-Se Battery.

Fabrication of transition-metal catalytic materials is regarded as a promising strategy for developing high-performance sodium-selenium (Na-Se) batteries. However, more systematic explorations are further demanded to find out how their bonding interactions and electronic structures canaffect the Na storage process. This study finds that lattice-distorted nickel (Ni) structure canform different bonding structures with Na2 Se4 , providing high activity to catalyze the electrochemical reactions in Na-Se batteries. Using this Ni structure to prepare electrode (Se@NiSe2 /Ni/CTs) canrealize rapid charge transfer and high cycle stability of the battery. The electrode exhibits high storage performance of Na+ ; i.e., 345 mAhg⁻1 at 1 C after 400 cycles, and 286.4 mAhg⁻1 at 10 C in rate performance test. Further results reveal the existence of a regulated electronic structure with upshifts of the d-band center in the distorted Ni structure. This regulation changes the interaction between Ni and Na2 Se4 to form a Ni3 -Se tetrahedral bonding structure. This bonding structure canprovide higher adsorption energy of Ni to Na2 Se4 to facilitate the redox reaction of Na2 Se4 during the electrochemical process. This study can inspire the design of bonding structure with high performance in conversion-reaction-based batteries.

Accurate Characterization of the Adhesive Layer Thickness of Ceramic Bonding Structures Using Terahertz Time-Domain Spectroscopy.

Ceramic adhesive structures have been increasingly used in aerospace applications. However, the peaks of the signal on the upper and lower surface of the adhesive layer are difficult to measure directly due to the thin thickness of the adhesive layer and the effect of the attenuation dispersion of the ceramic layer. Thus, the existing non-destructive testing techniques have been ineffective in detecting adhesive quality. In this paper, the thickness of the adhesive layer is measured using terahertz time-domain spectroscopy. A sparse deconvolution method is proposed for the terahertz time-domain spectral signal of ceramic adhesive structures with different adhesive layer thicknesses. The results show that the methods proposed in this paper can realize the separation of reflection signals for glue layers with a thickness of 0.20 mm. By comparing with a wavelet denoising method and a modified covariance method (AR/MCM), the effectiveness of the sparse deconvolution method in estimating the thickness of the glue layer is demonstrated. This work will provide the theoretical and experimental basis for using terahertz time-domain spectroscopy to detect the homogeneity of ceramic adhesive structures.

Nondestructive Evaluation of Composite Bonding Structure Used in Electrical Insulation Based on Active Infrared Thermography.

Nondestructive testing and evaluation of composite insulating components of electrical equipment is extremely necessary for assuring the safety of a power system. However, most existing nondestructive testing methods are not applicable for fast and effective live detection due to their time-consuming operation, high cost, and contact or near-field measurement. In this work, the effectiveness of active infrared thermography was investigated for detecting defects in silicone rubber (SIR)–fiber-reinforced plastic (FRP) bonding structures, which have been commonly used in insulating components of power equipment. The effectiveness of differential thermal image for enhancing the contrast of defective and sound areas and eliminating additive noise was demonstrated. Particularly, frame difference thermal image obtained by subtracting two differential thermal images extracting from respectively before and after the contrast inversion was proposed to enhance defect identification. The results revealed that defects of various sizes and depths such as voids, cracks, and interface disbonding of the SIR–FRP bonding structure were accurately detected by thermographic data. With the advantages of a quick and simple process, safety, universal applicability, visual results, far-field measurement, and quantitative defect estimation capabilities, active infrared thermography would be quite promising for live detection of electrical equipment.

Interface Characterization and Analysis of 4H-SiC Direct Bonding Structure Based on Plasma Processing

A plasma-assisted direct bonding method for 4H-SiC is put forward to prepare all-SiC vacuum-sealed cavity in this paper. This method takes three significant steps of bonding surface treatment, hydrophilic pre-bonding and hot pressing bonding. The SiC bonded sample with a cylindrical sealing cavity structure was prepared under a pressure of 2 MPa for a period of 1 h at 1000 °C using the direct bonding method. The bonded sample’s airtightness is approximately 0.1 × 10−9 pa·m3 s−1, and the bonding strength reaches 24.9 MPa, meeting the requirements of most pressure sensors. The cavity structure of the bonded sample is unbroken and the bonding interface is smooth without stress concentration under a scanning electron microscope (SEM). Transmission electron microscope (TEM) observation results reveal that bonding interface is amorphous with a thickness of less than 1 nm. The bonding interface is mainly composed of carbon and silicon which is analyzed through energy dispersive X-ray (EDX). It is speculated that the transition layer of ultrathin amorphous SiC is formed during bonding process. Finally, the SiC bonding mechanism is discussed in detail based on the experimental results. All-SiC bonding structures with a vacuum-sealed cavity can be applied to fabricate mechanical quantity sensors for use in severe environment.

(3-Aminopropyl)trimethoxysilane Self-Assembled Monolayer as Barrier of Porous SiOCH for Electroless Cu Metallization: Optimizations of SiOCH Hydroxylation and Monolayer Functionalization

Self-assembled monolayers (SAMs) are potential diffusion barriers of nanoporous carbon-doped organosilica (p-SiOCH) for Cu metallization. A concern regarding silanization of the p-SiOCH using a wet chemical process is that its dielectric properties and bonding structures could be damaged by the chemical solution used, which is rarely addressed. In this study, the capacity of various (3-aminopropyl)trimethoxysilane self-assembled monolayers (APTMS-SAMs) as a barrier of p-SiOCH for electroless Cu metallization is evaluated. The processing of hydroxylation of the p-SiOCH (for silanization) and functionalization of APTMS-SAMs (for seeding of electroless metallization) was controlled through examining dielectric properties and bond structures of the hydroxylated p-SiOCH and functionalized APTMS-SAMs. Through tailoring the wet chemical treatments, the dielectric constant, insulating capacity, and bonding structure of post-treated p-SiOCH could be preserved at the pristine states, and the APTMS-SAM fabricated turns out to be a reliable barrier thermally stable up to 500 °C, 100 °C greater than that of the p-SiOCH without an SAM barrier. The integration of electroless Cu metallization reliably with p-SiOCH using a near-zero-thickness monolayer (free of a conventional metallic barrier) in an all-wet manner will be demonstrated. However, to make this approach working, both the hydroxylation of p-SiOCH and functionalization of APTMS-SAM have to be optimized.

Bond Structures between Wood Components and Citric Acid in Wood-Based Molding.

Citric acid-based wood adhesive is considered a chemical-bonding wood adhesive. However, the detailed structures of the bonds between wood components and citric acid remain unknown. Here, we examine the chemical bonding structures between citric acid and wood by heteronuclear single quantum coherence-nuclear magnetic resonance (HSQC-NMR) analysis of wood-based molding using Japanese cedar (Cryptomeria japonica) and citric acid. In the HSQC-NMR spectrum of the wood molding, some esterified C/H correlation peaks appeared. The primary hydroxyl groups of polysaccharides, such as cellulose and galactoglucomannan, and the primary hydroxyl groups of the β-O-4 and β-5 substructures in lignin were found to be esterified with citric acid. In contrast, the secondary hydroxyl groups, except for xylan, barely reacted because of the steric hindrance. Additionally, the C/H correlation peak volumes of the reducing ends of mannan and xylan in the anomeric region increased after molding. It was clarified that the glycosidic bonds in the hemicelluloses were cleaved under the acidic molding condition with citric acid. The HSQC-NMR analysis revealed that the esterification of hemicellulose and lignin, and degradation of hemicellulose, proceeded under the molding condition. These results will promote understanding of the adhesive mechanism of citric acid-based wood adhesive and of the properties of the molding.

Direct Measurement of Electron Transfer Rates between Iron(II) Phthalocyanine and Gold with Different Interface Structures

Electron transfer in a metal/molecule system has been extensively studied using various methods. In particular, the relation between the structure of metal/molecule junctions and the electron transfer property is of great interest in the research field of molecular devices. In this study, we measured electron transfer rates of iron(II) phthalocyanine/gold system with different junctions to study the contribution of the atomistic interfacial structures to the electron transfer characteristics.An Au single-crystal disk with (111) or (100) orientation was modified with self-assembled monolayers of imidazole-terminated alkanethiols with the alkyl chain of ten carbon atoms (ImC10SH). Then, iron(II) phthalocyanine (FePc) complexes were attached on top of the monolayer through the axial ligation of the central Fe ions with the imidazole groups. The Au-S bonding structure was measured using Surface-enhanced Raman spectroscopy (SERS).1) The electron transfer rate between Au and FePc was measured by analyzing the cyclic voltammogram (CV) of redox behavior for FePc in 0.1 M perchloric acid aqueous solution.SERS measurements showed that the Au-S bonding structures were different between Au(111) and Au(100). According to the peak position of nAu-S, the dominant Au-S structure was determined to be three-fold hollow geometry on Au(111) and two-fold bridge geometry on Au(100). Figure shows the scan rate dependence of CVs of FePc/ImC10SH/Au(100) and FePc/ImC10SH/Au(111). With increasing the scan rate, the peak separation between the oxidation and reduction peaks became larger in both cases. However, the magnitude of the separation was larger for Au(111) than for Au(100), suggesting that the electron transfer through the Au-S junction was slower at the hollow site on Au(111) than at the bridge site on Au(100). The electron transfer rate can be calculated from the relation between the peak separation and the scan rate. We will present detailed quantitative analysis of the electron transfer rate for different Au-S bond structures, alkyl chain lengths, etc.1) M. Inagaki, K. Motobayashi, K, Ikeda, J. Phys. Chem. Lett., 8, 4236 (2017)Figure. Scan rate dependence of CVs of FePc/ImC10SH/Au(100) and, FePc/ImC10SH/Au(111) in 0.1 M perchloric acid aqueous solution. Figure 1

Multiscale Analysis on the Effect of Lap Length on Bonding Strength of Adhesively Bonding Structures of Plain Weave Composites

Multiscale Analysis on the Effect of Lap Length on Bonding Strength of Adhesively Bonding Structures of Plain Weave Composites

Element to Change the Bonding Structures of SnO 2 Thin Films

Element to Change the Bonding Structures of SnO 2 Thin Films

Identification and Characterization of Molecular Bonding Structures by ab initio Quasi-Atomic Orbital Analyses.

The quasi-atomic analysis of ab initio electronic wave functions in full valence spaces, which was developed in preceding papers, yields oriented quasi-atomic orbitals in terms of which the ab initio molecular wave function and energy can be expressed. These oriented quasi-atomic orbitals are the rigorous ab initio counterparts to the conceptual bond forming atomic hybrid orbitals of qualitative chemical reasoning. In the present work, the quasi-atomic orbitals are identified as bonding orbitals, lone pair orbitals, radical orbitals, vacant orbitals and orbitals with intermediate character. A program determines the bonding characteristics of all quasi-atomic orbitals in a molecule on the basis of their occupations, bond orders, kinetic bond orders, hybridizations and local symmetries. These data are collected in a record and provide the information for a comprehensive understanding of the synergism that generates the bonding structure that holds the molecule together. Applications to a series of molecules exhibit the complete bonding structures that are embedded in their ab initio wave functions. For the strong bonds in a molecule, the quasi-atomic orbitals provide quantitative ab initio amplifications of the Lewis dot symbols. Beyond characterizing strong bonds, the quasi-atomic analysis also yields an understanding of the weak interactions, such as vicinal, hyperconjugative and radical stabilizations, which can make substantial contributions to the molecular bonding structure.

Probing Chemical Bonding and Electronic Structures in ThO- by Anion Photoelectron Imaging and Theoretical Calculations.

Because of renewed research on thorium-based molten salt reactors, there is growing demand and interest in enhancing the knowledge of thorium chemistry both experimentally and theoretically. Compared with uranium, thorium has few chemical studies reported up to the present. Here we report the vibrationally resolved photoelectron imaging of the thorium monoxide anion. The electron affinity of ThO is first reported to be 0.707 ± 0.020 eV. Vibrational frequencies of the ThO molecule and its anion are determined from Franck-Condon simulation. Spectroscopic evidence is obtained for the two-electron transition in ThO-, indicating the strong electron correlation among the (7sσ)2(6dδ)1 electrons in ThO- and the (7sσ)2 electrons in ThO. These findings are explained by using quantum-chemical calculations including spin-orbit coupling, and the chemical bonding of gaseous ThO molecules is analyzed. The present work will enrich our understanding of bonding capacities with the 6d valence shell.

Collision Induced Unfolding of Intact Antibodies: Rapid Characterization of Disulfide Bonding Patterns, Glycosylation, and Structures.

Monoclonal antibodies (mAbs) are among the fastest growing class of therapeutics due to their high specificity and low incidence of side effects. Unlike most drugs, mAbs are complex macromolecules (∼150 kDa), leading to a host of quality control and characterization challenges inherent in their development. Recently, we introduced a new approach for the analysis of the intact proteins based on ion mobility-mass spectrometry (IM-MS). Our protocol involves the collision induced unfolding (CIU) of intact antibodies, where collisional heating in the gas-phase is used to generate unfolded antibody forms, which are subsequently separated by IM and then analyzed by MS. Collisional energy is added to the antibody ions in a stepwise fashion, and "fingerprint plots" are created that track the amount of unfolding undergone as a function of the energy imparted to the ions prior to IM separation. In this report, we have used these fingerprints to rapidly distinguish between antibody isoforms, possessing different numbers and/or patterns of disulfide bonding and general levels of glycosylation. In addition, we validate our CIU protocols through control experiments and systematic statistical evaluations of CIU reproducibility. We conclude by projecting the impact of our approach for antibody-related drug discovery and development applications.

X-ray photoelectron spectroscopy study of high-k CeO2/La2O3 stacked dielectrics

This work presents a detailed study on the chemical composition and bond structures of CeO2/La2O3 stacked gate dielectrics based on x-ray photoelectron spectroscopy (XPS) measurements at different depths. The chemical bonding structures in the interfacial layers were revealed by Gaussian decompositions of Ce 3d, La 3d, Si 2s, and O 1s photoemission spectra at different depths. We found that La atoms can diffuse into the CeO2 layer and a cerium-lanthanum complex oxide was formed in between the CeO2 and La2O3 films. Ce3+ and Ce4+ states always coexist in the as-deposited CeO2 film. Quantitative analyses were also conducted. The amount of CeO2 phase decreases by about 8% as approaching the CeO2/La2O3 interface. In addition, as compared with the single layer La2O3 sample, the CeO2/La2O3 stack exhibits a larger extent of silicon oxidation at the La2O3/Si interface. For the CeO2/La2O3 gate stack, the out-diffused lanthanum atoms can promote the reduction of CeO2 which produce more atomic oxygen. This result confirms the significant improvement of electrical properties of CeO2/La2O3 gated devices as the excess oxygen would help to reduce the oxygen vacancies in the film and would suppress the formation of interfacial La-silicide also.

Understanding Local Bonding Structures of Ni-Doped Chromium Nitride Coatings through Synchrotron Radiation NEXAFS Spectroscopy

CrN has widespread applications as protective coatings, for example, in aircraft jet engines whereby their high hardness and good oxidation resistance render metal components resistant to harsh operating conditions. Alloying elements are commonly incorporated (doped) into the coatings to further enhance their thermomechanical properties. However, the effect of dopants on the electronic properties and their roles in modifying the grain boundary configurations remain unclear. Lack of such critical knowledge has hindered the development of design strategies for high performance CrN-based coatings. To address this challenging issue, in the present study near-edge X-ray absorption fine structure (NEXAFS) investigations of Cr1–yNiyN coatings at the Cr L3,2-edge (570–610 eV), Ni L3,2-edge (840–890 eV), and N K-edge (380–450 eV) regions were conducted using synchrotron radiation soft X-ray (SXR) spectroscopy in both Auger electron yield (AEY) and total fluorescence yield (TFY) modes. The chemical states in CrNiN were found to change with the increase of Ni content, manifested as a small chemical shift and moderate change of shapes of various absorption edges. The CrN grain size also became smaller with increasing Ni concentration. These findings help improve our understanding of local bonding structures, which could potentially lead to improved coating designs for highly demanding applications.

物理気相成長法による超ナノ微結晶ダイヤモンド/水素化アモルファスカーボン混相膜の創製とその化学結合構造

物理気相成長法による超ナノ微結晶ダイヤモンド/水素化アモルファスカーボン混相膜の創製とその化学結合構造

Influence of Disbond Defects on the Dispersion Properties of Adhesive Bonding Structures

With increasing application of adhesive bonding structures, the quality assessment of adhesive bonding became critical. Ultrasonic approach was an acknowledged promising method in many Nondestructive testing (NDT) techniques. The research object was to use analytical models to develop a quantitative understanding of the affections in different situations on the dispersion properties. An improved global matrix method was introduced to compute the dispersive curves, which can effectively eliminate the instability for thicker layers and higher frequencies. In order to evaluate the disbond defect, the cohesive strength degradation mode and the spring mode were then adopted to describe the cohesive failure and the interface failure, respectively. In the paper, cohesive failure, interface failure and mixed failure were analyzed for the steel/adhesive layer/insulation layered structure. Interface failure induced the modes of multilayer structure to regress to the modes of single layers, while the cohesive failure made the dispersive curves move to the lower frequency direction, and changing the relative position of spring layer led the dispersive curves shift to the higher frequency direction. Among all the factors, the interface failure was dominant. Finally, the variety of the dispersive modes in a special frequency band (1~1.5MHz) was found that can be regarded as parameters of the adhesive bonding quality.

Analyses of plasma reactive sputter deposition of CNx films by OES

Adding Ar to the sputtering gas N2 had influence upon the species distribution in the gas phase. Our experimental results suggest that the N-to-C ratio is not sensitive to the local binding states of elements in the CNx films. In order to increase the percentage of one of desired bonding structures in the film it is relatively limited by means of optimizing the discharge parameters such as the voltage of graphite target and flow ratio of sputtering gases. Other methods such as physical and/or chemical treatments of deposition surface may be effective. As reported work shows, increasing temperature of substrate is useful to decomposition of parayanogen structure[2] or impact of ions on deposition surface to formsp 3 bond structurer[1]. It is believed that finding new methods of deposition surface treatments is worth further considering if we hope to deposit and increase one of desired percentage ofbond structure in the films.

Closed-Form Solution for Thermo-Elastoplastic Strains in Semiconductor Chip Bonding Structures

A closed-form solution is presented for calculating the strains produced by temperature changes in semiconductor chip bonding structures ; it is based on beam theory and elasto-perfect plastic bonding layer assumptions. This solution agrees well with three-dimensional FEM and experimental results. The parameters that govern the strains produced in bonding structures are derived from this solution. These parameters are charted in order to obtain the maximum shearing strains of bonding layers and the maximum normal stresses of chips.

New Parameter for Controlling Strains in Semiconductor Chip Bonding Structures with Multi-Bonding Layers.

A new parameter, Cij, is proposed for taking into account the effects of the interaction of multi-bonding layers on the strains of bonding layers with nonelastic behavior in semiconductor chip bonding structures under temperature changes. The previously proposed strain solution of a single bonding layer is extended to the solution of multi-bonding layers through use of this new parameter. This solution shows good agreement with FEM results. It is found from the consideration of sample structures that Cij is a useful parameter for optimizing multi-bonding layer structures.