Search results for "interfacial"

Interfacial engineering for single and multijunction vacuum-deposited perovskite solar cells

2019

Use of micro-tomography for validation of method to identify interfacial shear strength from tensile tests of short regenerated cellulose fibre compo…

2016

The interfacial shear strength of short regenerated cellulose fibre/polylactide composites was characterized by means of an industry-friendly adhesion test method. The interfacial shear strength was back-calculated from the experimental tensile stress-strain curves of composites by using a micro-mechanical model. The parameters characterizing the microstructure of the composites, e.g. fibre length and orientation distributions, used as input in the model were obtained by micro-tomography. The investigation was carried out on composites with untreated and surface treated fibres with various fibre weight contents (5wt%, 10wt%, and 15wt% for untreated fibres, and 15wt% for treated fibres). The…

Evaluation of interfacial stress transfer efficiency by coating fragmentation test

2007

Probabilistic model of coating fragmentation under uniaxial tensile loading is developed. Analytical expressions of the crack spacing evolution are obtained for small-strain and large-strain fragmentation regimes. The model is applied for coating and interface property identification of several thin brittle coating/polymer substrate systems. An estimate of the stress transfer length, derived from the fragmentation data, is found to correlate with the interfacial shear strength thus suggesting that both parameters reflect an intrinsic property related to the mechanical efficiency of coating/substrate interface.

Phonon Bridge Effect in Superlattices of Thermoelectric TiNiSn/HfNiSn With Controlled Interface Intermixing

2020

© 2020 by the authors

Kapitza resistance of laser-annealed surfaces

1984

Our understanding of the phonon processes at the interfaces between two media is still quite rudimentary. Particularly notorious is the helium-solid interface, where the accoustic impedances differ by a large amount. It is well known that the Kapitza resistance, i.e. the thermal boundary resistance between helium and a solid, is usually up to 100 times smaller than predicted by the acoustic theory as formulated by Khalatnikov [1]. However, it was shown by J. WEBER et al. [2] that there was no discrepancy at surfaces of freshly cleaved crystals, i.e. at surfaces of exceptional good quality. Thus it is clear that surface irregularities must be responsible for the anomalous Kapitza resistance.…

Magnetic Polyurethane Microcarriers from Nanoparticle-Stabilized Emulsions for Thermal Energy Storage

2020

Hydrated inorganic salts are phase change materials (PCMs) with promising thermal energy storage capacity. However, their application is commonly restricted because of problems of phase segregation...

Electrochemical Analysis of Catalytic and Oxygen Interfacial Transfer Effects on MnO2 Deposited on Gold Electrodes

2018

[EN] A theoretical model for obtaining thermochemical and kinetic information on oxygen interfacial transfer in metal oxides deposited on gold electrodes, based in the voltammetry of immobilized particle methodology, is presented. It is applied to MnO2 microparticulate deposits on gold in contact with aqueous NaOH solution using the voltammetric signals for the oxidation of gold to gold oxide monolayer and its subsequent desorptive reduction. Assuming reversibility, voltammetric peak potentials permit to estimate a variation of Gibbs free energy of interfacial oxygen transfer of -32 +/- 3 kj mol(-1). Analysis of peak current data based on the Sharp-Hancock formalism of solid-state kinetics …

ZnS Ultrathin interfacial layers for optimizing carrier management in Sb2S3-based photovoltaics

2021

Antimony chalcogenides represent a family of materials of low toxicity and relative abundance, with a high potential for future sustainable solar energy conversion technology. However, solar cells based on antimony chalcogenides present open-circuit voltage losses that limit their efficiencies. These losses are attributed to several recombination mechanisms, with interfacial recombination being considered as one of the dominant processes. In this work, we exploit atomic layer deposition (ALD) to grow a series of ultrathin ZnS interfacial layers at the TiO2/Sb2S3 interface to mitigate interfacial recombination and to increase the carrier lifetime. ALD allows for very accurate control over th…

Nanotribological, nanomechanical and interfacial characterization of atomic layer deposited TiO2 on a silicon substrate

2015

Abstract For every coating it is critical that the coatings are sufficiently durable to withstand practical applications and that the films adhere well enough to the substrate. In this paper the nanotribological, nanomechanical and interfacial properties of 15–100 nm thick atomic layer deposited (ALD) TiO 2 coatings deposited at 110–300 °C were studied using a novel combination of nanoscratch and scanning nanowear testing. Thin film wear increased linearly with increasing scanning nanowear load. The film deposited at 300 °C was up to 58±11 %-points more wear-resistant compared to the films deposited at lower temperatures due to higher hardness and crystallinity of the film. Amorphous/nanocr…

Interfacial disorder of graphene grown at high temperatures on 4H-SiC(000-1)

2016

This paper presents an investigation of the morphological and structural properties of graphene (Gr) grown on SiC(000-1) by thermal treatments at high temperatures (from 1850 to 1950 ºC) in Ar at atmospheric pressure. Atomic force microscopy and micro-Raman spectroscopy showed that the grown Gr films are laterally inhomogeneous in the number of layers, and that regions with different stacking-type (coupled or decoupled Gr films) can coexist in the same sample. Scanning transmission electron microscopy and electron energy loss spectroscopy showed that a nm-thick C-Si-O amorphous layer is present at the interface between Gr and SiC. Basing on these structural results, the mechanisms of Gr gro…