Structure-property Interplay Research Articles

Structure–Property Interplay Within Microporous Manganese Dioxide Tunnels For Sustainable Energy Storage

AbstractTunnel‐structured manganese dioxides (MnO2), also known as octahedral molecule sieves (OMS), are widely studied in geochemistry, deionization, energy storage and (electro)catalysis. These functionalities originate from their characteristic sub‐nanoscale tunnel framework, which, with a high degree of structural polymorphism and rich surface chemistry, can reversibly absorb and transport various ions. An intensive understanding of their structure–property relationship is prerequisite for functionality optimization, which has been recently approached by implementation of advanced (in situ) characterizations providing significant atomistic sciences. This review will thus timely cover recent advancements related to OMS and their energy storage applications, with a focus on the atomistic insights pioneered by researchers including our group: the origins of structural polymorphism and heterogeneity, the evolution of faceted OMS crystals and its effect on electrocatalysis, the ion transport/storage properties and their implication for processing OMS. These studies represent a clear rational behind recent endeavors investigating the historically applied OMS materials, the summary of which is expected to deepen the scientific understandings and guide material engineering for functionality control.

Structure-Property Interplay Within Microporous Manganese Dioxide Tunnels For Sustainable Energy Storage.

Tunnel-structured manganese dioxides (MnO2 ), also known as octahedral molecule sieves (OMS), are widely studied in geochemistry, deionization, energy storage and (electro)catalysis. These functionalities originate from their characteristic sub-nanoscale tunnel framework, which, with a high degree of structural polymorphism and rich surface chemistry, can reversibly absorb and transport various ions. An intensive understanding of their structure-property relationship is prerequisite for functionality optimization, which has been recently approached by implementation of advanced (in situ) characterizations providing significant atomistic sciences. This review will thus timely cover recent advancements related to OMS and their energy storage applications, with a focus on the atomistic insights pioneered by researchers including our group: the origins of structural polymorphism and heterogeneity, the evolution of faceted OMS crystals and its effect on electrocatalysis, the ion transport/storage properties and their implication for processing OMS. These studies represent a clear rational behind recent endeavors investigating the historically applied OMS materials, the summary of which is expected to deepen the scientific understandings and guide material engineering for functionality control.

Unexpected Near-Infrared to Visible Nonlinear Optical Properties from 2-D Polar Metals.

Near-infrared-to-visible second harmonic generation from air-stable two-dimensional polar gallium and indium metals is described. The photonic properties of 2D metals, including the largest second-order susceptibilities reported for metals (approaching 10 nm/V), are determined by the atomic-level structure and bonding of two-to-three-atom-thick crystalline films. The bond character evolved from covalent to metallic over a few atomic layers, changing the out-of-plane metal-metal bond distances by approximately ten percent (0.2 Å), resulting in symmetry breaking and an axial electrostatic dipole that mediated the large nonlinear response. Two different orientations of the crystalline metal atoms, corresponding to lateral displacements <2 Å, persisted in separate micrometer-scale terraces to generate distinct harmonic polarizations. This strong atomic-level structure-property interplay suggests metal photonic properties can be controlled with atomic precision.

New Structure-Nonlinear Optical Property Correlation in “Russian Doll” Complexes Formed by Nested Pd(II) Nanorings

In an attempt to reveal a new structure–property interplay between the relative cavity size of the host–guest nanohoop complexes and nonlinear optical (NLO) responses, a series of “Russian doll” co...

Structure-property interplay of asymmetric membranes comprising of soft polydimethylsiloxane chains and hard silica nanomaterials

Silica nanomaterials modified with monomolecular C18-alkyl silane or oligomeric dimethylsiloxane units were loaded in-situ during the formation of PDMS membrane. The small-angle neutron scattering (SANS) study was performed to probe structural compatibility between the modified silica and PDMS. The Ornstein-Zernike (OZ) and Debye-Anderson-Brumberger (DAB) models were excellently fit to the SANS data describing nanoscale structure morphology in terms of correlation length scales of the soft and hard segmental units. The polymeric chain was stretched or contracted depending upon the type and amount of silica incorporation. This indicated limiting amount of silica incorporation in the PDMS membrane structure depending upon structural compatibility between the silica and PDMS. The C18-alkyl silylated silica was found to be the best compatible with the membrane structure. The membrane with 30% (w/w) C18-alkyl silylated -silica loading exhibited the best performance in pervaporation separation of alcohol/water.

High quality epitaxial fluorine-doped SnO2 films by ultrasonic spray pyrolysis: Structural and physical property investigation

Despite its wide use in the display and photovoltaic industries, fluorine-doped tin oxide (F:SnO2, FTO) has been studied only in its polycrystalline form. In this work, we report on the first growth of epitaxial FTO thin film by ultrasonic spray pyrolysis – a simple chemical deposition method – and we reveal the structure-property interplay by investigating in details its growth, morphology and strain/defects. Epitaxial FTO films are successfully grown on (110) rutile TiO2 single crystals and form mosaic domains with an out-of-plane distribution smaller than 0.5°, showing high structural quality comparable to epitaxial films prepared by molecular beam epitaxy and pulsed-laser deposition. Owing to the large lattice mismatch with rutile TiO2, the FTO film develops significant structural defects to release the epitaxial strain and is consequently nearly fully relaxed with a slight residual strain of 0.1–0.2%. With the help of an innovative nano-beam precession electron diffraction technique, the strain distribution is mapped at the TiO2/FTO interface, from which we identify the interfacial and secondary strain relaxation taking place mainly in the first 22nm in the FTO film. The Hall-mobility of the epitaxial FTO films is close to the state-of-the-art and expected to improve further at lower doping concentrations.

Comparison of two different carbon nanotubes-based hybrid multiscale composites with respect to mechanical and electrical properties

ABSTRACTPristine and carboxylic acid functionalised carbon nanotubes (CNTs-P and CNTs-COOH) hybrid composites based on ultrasonically processed nanocomposite epoxy matrix have been prepared. The thermodynamic interactions between CNTs and epoxy components are evaluated through solution experiment. The measurements of mechanical properties and volume electrical resistivity are performed to characterise the structure-property interplay of CNTs hybrid composites. A 0.3 wt-% CNTs-COOH loading significantly enhances the glass transition temperatures (Tg) of the resultant hybrid composites. The re-agglomeration of CNTs-P has been ascribed to the thermodynamic and kinetic factors, which determine the morphological characteristics of CNTs within the overall composites. CNTs-P network enables a continuous conductive path to be present in the composites at lower CNTs-P concentration. An analysis of the effects of the functionalisation of CNTs on the structure and properties of their hybrid composites has been carried out.

A structure-property interplay between the width and height of cages and the static third order nonlinear optical responses for fullerenes: applying gamma density analysis.

To reveal a new structure-property relationship regarding the nonlinear optical (NLO) properties of fullerenes that are associated with gamma (γ) density, fullerenes I (C40, C50, C60 and C70), whose heights range from 4.83 to 7.96 Å, and II (C24, C36, C48 and C72), whose widths range from 4.45 to 8.22 Å, have been the research objects. Calculation of their geometric and electronic structures, absorption spectra, and the second hyperpolarizability (γ) and the γ density analysis have been performed. It is found that the electronic spatial extent and the polarizability (α) value increase linearly as the fullerenes increase by every 12 carbon atoms. Similarly, the γ values are also proportional to the fullerene size. It is worth noting that the relative magnitude of γxxxx and γzzzz was exactly consistent with that of the width and height of fullerenes. The analysis of γ density provides the essential reason for this result, that is, the magnitude of the contribution to γ values associated with γ densities is proportional to the density amplitudes multiplied by the distance between them. Larger fullerenes possess larger density amplitudes and longer distances, resulting in larger γ values with respect to smaller fullerenes. This work presents a new structure-property interplay between the width and height of the fullerenes and their second hyperpolarizability γ. Moreover, the γ density analysis provides a new insight to explore the nature of the relationship between the structure and the NLO properties.

Towards the modeling of quantum-dot sensitized solar cells: from structural and vibrational features to electron injection through lattice-mismatched interfaces

Structure-property interplay investigation in quantum dot solar cells, using a combined experimental and theoretical approach.

Probing the Structure-Property Interplay of Plasmonic Nanoparticle Transducers Using Femtosecond Laser Spectroscopy.

The characteristic feature of noble metal nanoparticles is the localized surface plasmon resonance (LSPR). Plasmon-supporting nanoparticles can function as transducers because of the LSPR's ability to amplify electromagnetic fields and its sensitivity to changes in the surrounding dielectric. The performance of these materials in transducer applications is inherently related to nanoparticle structure. This Perspective describes the use of femtosecond laser-based spectroscopies to elucidate the nanoscale structure-property interplay. First, femtosecond time-resolved transient extinction measurements that probe the LSPR following nanoparticle photoexcitation are described. These measurements illustrate how nanostructure dimensions influence sensitivity to changes in the interfacial dielectric. The combination of single-particle nonlinear optical (NLO) measurements and electron microscopy is also used to describe the symmetry of plasmon surface fields in nanoparticle assemblies. In particular, the use of continuous polarization variation-detected second-harmonic generation to describe electric and magnetic dipolar contributions to NLO properties is discussed.