| 1. |
- Auroux, Etienne, et al.
(författare)
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Evidence and Effects of Ion Transfer at Active-Material/Electrode Interfaces in Solution-Fabricated Light-Emitting Electrochemical Cells
- 2021
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Ingår i: Advanced Electronic Materials. - : Wiley-Blackwell Publishing Inc.. - 2199-160X. ; 7:8
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Tidskriftsartikel (refereegranskat)abstract
- The light-emitting electrochemical cell (LEC) allows for energy- and cost-efficient printing and coating fabrication of its entire device structure, including both electrodes and the single-layer active material. This attractive fabrication opportunity is enabled by the electrochemical action of mobile ions in the active material. However, a related and up to now overlooked issue is that such solution-fabricated LECs commonly comprise electrode/active-material interfaces that are open for transfer of the mobile ions, and it is herein demonstrated that a majority of the mobile anions in a common spray-coated active material can transfer into a spray-coated poly(3,4-ethylenedioxythiophene):poly(styrene-sulfonate) (PEDOT:PSS) positive electrode during LEC operation. Since it is well established that the mobile ion concentration in the active material has a profound influence on the LEC performance, this significant ion transfer is an important factor that should be considered in the design of low-cost LEC devices that deliver high performance.
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| 2. |
- Boota, M., et al.
(författare)
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Mechanistic Understanding of the Interactions and Pseudocapacitance of Multi-Electron Redox Organic Molecules Sandwiched between MXene Layers
- 2021
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Ingår i: Advanced Electronic Materials. - : Wiley. - 2199-160X. ; 7:4, s. 2001202-
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Tidskriftsartikel (refereegranskat)abstract
- Using a combined theoretical and experimental approach, a mechanistic understanding of the interactions and pseudocapacitance of different quinone-coupled viologen and pyridiniumium molecules sandwiched between titanium carbide (Ti3C2Tx) MXene layers has been provided. Three different derivatives of quinone-coupled viologen and pyridiniumium are synthesized using nucleophilic substitution reaction and subsequently hybridized with Ti3C2Tx MXene (organic@Ti3C2Tx) using self-assembly approach. The atomic structure of pristine Ti3C2Tx and organic@Ti3C2Tx hybrid films is investigated using grazing incidence X-ray diffraction and X-ray pair distribution function analysis using synchrotron radiation. Spectroscopic results confirm the coupling of quinones with viologen and pyridiniumium molecules and their non-covalent functionalization to the MXene without their catalytic decomposition. First-principles calculations confirm that the preferred orientation of organic molecules upon intercalation/adsorption is horizontal to the Ti3C2Tx surface. The authors reveal that these molecules attach to the Ti3C2Tx surface with a significantly high binding energy (up to −2.77 eV) via a charge transfer mechanism. The electronic structure calculations show that all organic@Ti3C2Tx hybrids preserved their metallic behavior. Free-standing organic@Ti3C2Tx hybrid films show a more than three times higher capacitance at ultra-high scan rates (up to 20 V s−1) compared to their pristine counterpart due to molecular pillaring of organic molecules between Ti3C2Tx layers via strong binding energies and charge transfer.
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| 4. |
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| 5. |
- Brett, Calvin, et al.
(författare)
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Humidity-Induced Nanoscale Restructuring in PEDOT:PSS and Cellulose Nanofibrils Reinforced Biobased Organic Electronics
- 2021
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Ingår i: Advanced Electronic Materials. - : Wiley. - 2199-160X. ; 7:6, s. 2100137-
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Tidskriftsartikel (refereegranskat)abstract
- In times where research focuses on the use of organic polymers as a base for complex organic electronic applications and improving device efficiencies, degradation is still less intensively addressed in fundamental studies. Hence, advanced neutron scattering methods are applied to investigate a model system for organic electronics composed of the widely used conductive polymer blend poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) together with nanocellulose as flexible reinforcing template material. In particular, the impact of relative humidity (RH) on the nanostructure evolution is studied in detail. The implications are discussed from a device performance point of view and the changing nanostructure is correlated with macroscale physical properties such as conductivity. The first humidification (95% RH) leads to an irreversible decrease of conductivity. After the first humidification cycle, however, the conductivity can be reversibly regained when returning to low humidity values (5% RH), which is important for device manufacturing. This finding can directly contribute to an improved usability of emerging organic electronics in daily live.
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| 6. |
- Brondin, Carlo Alberto, et al.
(författare)
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Tailoring Magnetic Anisotropy in Ultrathin Cobalt by Surface Carbon Chemistry
- 2024
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Ingår i: Advanced Electronic Materials. - 2199-160X. ; 10:4
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Tidskriftsartikel (refereegranskat)abstract
- The ability to manipulate magnetic anisotropy is essential for magnetic sensing and storage tools. Surface carbon species offer cost-effective alternatives to metal-oxide and noble metal capping layers, inducing perpendicular magnetic anisotropy in ultrathin ferromagnetic films. Here, the different mechanisms by which the magnetism in a few-layer-thick Co thin film is modified upon adsorption of carbon monoxide (CO), dispersed carbon, and graphene are elucidated. Using X-ray microscopy with chemical and magnetic sensitivity, the in-plane to out-of-plane spin reorientation transition in cobalt is monitored during the accumulation of surface carbon up to the formation of graphene. Complementary magneto-optical measurements show weak perpendicular magnetic anisotropy (PMA) at room temperature for dispersed carbon on Co, while graphene-covered cobalt exhibits a significant out-of-plane coercive field. Density-functional theory (DFT) calculations show that going from CO/Co to C/Co and to graphene/Co, the magnetocrystalline and magnetostatic anisotropies combined promote out-of-plane magnetization. Anisotropy energies weakly depend on carbidic species coverage. Instead, the evolution of the carbon chemical state from carbidic to graphitic is accompanied by an exponential increase in the characteristic domain size, controlled by the magnetic anisotropy energy. Beyond providing a basic understanding of the carbon-ferromagnet interfaces, this study presents a sustainable approach to tailor magnetic anisotropy in ultrathin ferromagnetic films. Magnetic properties of Co ultrathin films are shown to undergo dramatic changes upon surface carbon accumulation. Chemical transformation from molecular carbon monoxide to surface carbide and to a graphene layer progressively enhances the perpendicular magnetic anisotropy of Co. Calculations reveal that magnetocrystalline and magnetostatic contributions play distinctly different roles for the different carbon species.image
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| 7. |
- Brorsson, Joakim, 1988, et al.
(författare)
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Strategic Optimization of the Electronic Transport Properties of Pseudo-Ternary Clathrates
- 2022
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Ingår i: Advanced Electronic Materials. - : Wiley. - 2199-160X .- 2199-160X. ; 8:3
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Tidskriftsartikel (refereegranskat)abstract
- While alloying is a powerful handle for materials engineering, it is an ongoing challenge to navigate the large and complex parameter space of these materials. This applies in particular for thermoelectrics and even more so clathrates. Here, a combination of density functional theory calculations, alloy cluster expansions, Monte Carlo simulations, and Boltzmann transport theory calculations is used to identify compositions that yield high power factors in the pseudo-ternary clathrates Ba8AlxGayGe46−x−y and Ba8GaxGeySi46−x−y, while accounting for weight and raw material costs. The results show how a cost-efficient performance can be achieved by reducing the number of Al and Ga atoms per unit cell, while compensating the resulting increase in the carrier concentration via an extrinsic dopant. The approach used in this study is transferable and can be a useful tool for mapping the thermodynamic and transport properties of other multinary systems.
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| 8. |
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| 9. |
- Campion, James, 1989-, et al.
(författare)
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Ultra‐Wideband Integrated Graphene‐Based Absorbers for Terahertz Waveguide Systems
- 2022
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Ingår i: Advanced Electronic Materials. - : Wiley. - 2199-160X. ; 8:9, s. 2200106-2200106
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Tidskriftsartikel (refereegranskat)abstract
- This article presents novel graphene-based absorber materials which can be directly integrated in terahertz waveguide systems. A simple, low-cost integration method is developed, allowing graphene augmented inorganic nanofibers to be embedded inside a metallic waveguide. In contrast to existing absorbers, the ability to embed such materials in a metallic waveguide allows them to be integrated into complete terahertz systems for large-scale applications. The electromagnetic properties of such materials are then examined using standard network analysis techniques. A wideband measurement setup is developed to enable measurement of a single sample from 67 to 500 GHz, eliminating the need to fabricate multiple samples. The porosity of the integrated material leads to excellent electromagnetic performance across a wide range of frequencies. The samples are found to have a reflection coefficient less than −10 dB for frequencies above200 GHz, while their attenuation per unit length exceeds 35 dB mm−1. The low reflectivity of the material allows it to be used in systems applications where undesired reflections must be avoided. The electromagnetic shielding effectiveness of the material is assessed, with a total effectiveness of 20–45 dB observed for 0.84 mm thick samples.
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| 10. |
- Darabi, Sozan, 1994, et al.
(författare)
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Polymer-Based n-Type Yarn for Organic Thermoelectric Textiles
- 2023
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Ingår i: Advanced Electronic Materials. - : Wiley. - 2199-160X .- 2199-160X. ; 9:4
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Tidskriftsartikel (refereegranskat)abstract
- A conjugated-polymer-based n-type yarn for thermoelectric textiles is presented. Thermoelectric textile devices are intriguing power sources for wearable electronic devices. The use of yarns comprising conjugated polymers is desirable because of their potentially superior mechanical properties compared to other thermoelectric materials. While several examples of p-type conducting yarns exist, there is a lack of polymer-based n-type yarns. Here, a regenerated cellulose yarn is spray-coated with an n-type conducting-polymer-based ink composed of poly(benzimidazobenzophenanthroline) (BBL) and poly(ethyleneimine) (PEI). The n-type yarns display a bulk electrical conductivity of 8 × 10−3 S cm−1 and Seebeck coefficient of −79 µV K−1. A promising level of air-stability for at least 13 days can be achieved by applying an additional thermoplastic elastomer coating. A prototype in-plane thermoelectric textile, produced with the developed n-type yarns and p-type yarns, composed of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)-coated regenerated cellulose, displays a stable device performance in air for at least 4 days with an open-circuit voltage per temperature difference of 1 mV °C−1. Evidently, polymer-based n-type yarns are a viable component for the construction of thermoelectric textile devices.
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