Search results for "SCOPE"
showing 10 items of 2420 documents
Insights into Kelvin probe force microscopy data of insulator-supported molecules
2015
We present a detailed analysis and understanding of Kelvin probe force microscopy (KPFM) data for a system of point charges in a vacuum-dielectric tip-sample system. Explicit formulae describing the KPFM signal $\ensuremath{\Delta}V$ are derived for the two KPFM operation modes, namely amplitude modulation and frequency modulation (FM). The formulae allow for a physical interpretation of the resulting KPFM signal, reveal contributing parameters, and especially disclose an additive behavior. We numerically evaluate these equations and show exemplary KPFM slice data for a single point charge. The theoretical analysis is complemented by two-dimensional FM-KPFM maps obtained experimentally on 2…
Assessment of Polarity in GaN Self-Assembled Nanowires by Electrical Force Microscopy
2015
In this work, we demonstrate the capabilities of atomic force microscopies (AFMs) for the nondestructive determination of the polarity of GaN nanowires (NWs). Three complementary AFMs are analyzed here: Kelvin probe force microscopy (KPFM), light-assisted KPFM, and piezo-force microscopy (PFM). These techniques allow us to assess the polarity of individual NWs over an area of tens of μm(2) and provide statistics on the polarity of the ensemble with an accuracy hardly reachable by other methods. The precise quantitative analysis of the tip-sample interaction by multidimensional spectroscopic measurements, combined with advanced data analysis, has allowed the separate characterization of elec…
Studies of host-guest thin films of corona-poled betaine-type polar molecules by kelvin probe technique and atomic force microscopy
2004
In this work betaine-type molecules were investigated. As a result of the asymmetry of charge distribution, molecules possess in the ground state a considerable permanent dipole moment. The decay of surface potential of poled polymer films is dependent at least on two relaxation processes. The influence of glass transition of PMMA on thermal dependence of the surface potential is shown. The transition temperature, where no changes of the surface potential appeared, is related to glass transition temperature of the host-guest system. The topography of the film surface was obtained by AFM.
Kelvin probe force microscopy studies of the charge effects upon adsorption of carbon nanotubes and C 60 fullerenes on hydrogen-terminated diamond
2018
Hydrogen-terminated diamond is known for its unusually high surface conductivity that is ascribed to its negative electron affinity. In the presence of acceptor molecules, electrons are expected to transfer from the surface to the acceptor, resulting in p-type surface conductivity. Here, we present Kelvin probe force microscopy (KPFM) measurements on carbon nanotubes and C60 adsorbed onto a hydrogen-terminated diamond(001) surface. A clear reduction in the Kelvin signal is observed at the position of the carbon nanotubes and C60 molecules as compared with the bare, air-exposed surface. This result can be explained by the high positive electron affinity of carbon nanotubes and C60, resulting…
The Interplay of Contact Layers: How the Electron Transport Layer Influences Interfacial Recombination and Hole Extraction in Perovskite Solar Cells.
2018
Charge-selective contact layers in perovskite solar cells influence the current density–voltage hysteresis, an effect related to ion migration in the perovskite. As such, fullerene-based electron transport layers (ETLs) suppress hysteresis by reducing the mobile ion concentration. However, the impact of different ETLs on the electronic properties of other constituent device layers remains unclear. In this Kelvin probe force microscopy study, we compared potential distributions of methylammonium lead iodide-based solar cells with two ETLs (planar TiO2 and C60-functionalized self-assembled monolayer) with different hysteretic behavior. We found significant changes in the potential distributio…
Light-induced charge separation in a donor–chromophore–acceptor nanocomposite poly[TPA-Ru(tpy)2]@ZnO
2013
The synthesis and characterisation of a new donor–chromophore–acceptor system based on poly(vinyltriphenylamine) as the electron donor and a glycine-functionalised bis(2,2′;6′,2′′-terpyridine)ruthenium(II) complex acting both as a chromophore and as an anchor group attached to ZnO nanorods as the electron acceptor are described. The TPA-containing block copolymer was synthesised by Reversible Addition Fragmentation Chain Transfer (RAFT) polymerisation and the ruthenium complex glycine conjugates prepared by Solid Phase Peptide Synthesis (SPPS) were attached via post-polymerisation esterification. GPC, NMR, IR and UV-Visible spectroscopy were used to characterise the multifunctional chromoph…
Cosmic ray composition and energy spectrum from 1–30 PeV using the 40-string configuration of IceTop and IceCube
2012
Astroparticle physics 42, 15 - 32 (2013). doi:10.1016/j.astropartphys.2012.11.003
EA Planning, Development and Management Process for Agile Enterprise Development
2005
In this study, we suggest an enterprise architecture (EA) development process model suitable for EA projects limited in scope and time. Several EA process models have been put forward, which have in common the idea of comprehensive EA management and development that is generic, cyclic and ongoing in a user organization. The suggested models are of varying level of abstraction. It is not simple to select the right issues from them for a restricted development effort. An ICT services provider needs a process model to follow in EA consulting and development projects. This approach is also needed for incremental EA development by user organizations. Starting with the suggested EA process models…
Extending the international new venture phenomenon to digital platform providers : A longitudinal case study
2018
People increasingly interact with services enabled by digital platforms. This has been a consequence of the digitalization of artifacts, which has transmuted traditional businesses into digital forms. With the increasing digitalization and modularization of services, digital platforms have given many digital service providers possibilities to scale globally, and to rapidly transcend national borders by serving multi-sided markets. However, we still know very little about how digital platform providers actually internationalize their services, or how they make their platforms available for global markets. In this paper, we contribute to the increasing literature on digital-based INVs, examin…
Synthesis, characterization and study of covalently modified triazole LAPONITE® edges
2020
Abstract LAPONITE® (Lap) clay mineral was successful functionalized by triazole groups in a two steps procedure. First, the Lap edges were modified with 3-azidopropyltrimethoxysilane by traditional heating and microwave irradiation. Microwave irradiation allowed us to obtain high loading onto the Lap edges in lower times compared to those obtained through conventional method. Afterwards, the triazole moieties were obtained by reaction between azido functionalized Lap and propargyl alcohol. The successful functionalization of Lap was proved by thermogravimetric analysis, FT-IR spectroscopy, dynamic light scattering and ζ-potential measurements. Finally, the effects of the surface modificatio…