| 1. |
- Andersson, Viktor, et al.
(författare)
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Imaging of the 3D Nanostructure of a Polymer Solar Cell by Electron Tomography
- 2009
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Ingår i: Nano letters (Print). - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 9:2, s. 853-855
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Tidskriftsartikel (refereegranskat)abstract
- Electron tomography has been used for analyzing the active layer in a polymer solar cell, a bulk heterojunction of an alternating copolymer of fluorene and a derivative of fullerene. The method supplies a three-dimensional representation of the morphology of the film, where domains with different scattering properties may be distinguished. The reconstruction shows good contrast between the two phases included in the film and demonstrates that electron tomography is an adequate tool for investigations of the three-dimensional nanostructure of the amorphous materials used in polymer solar cells.
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| 2. |
- Andersson, Viktor, et al.
(författare)
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Morphology of organic electronic materials imaged via electron tomography
- 2012
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Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 247:3, s. 277-287
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Tidskriftsartikel (refereegranskat)abstract
- Several organic materials and blends have been studied with the use of electron tomography. Tomography reconstructions of active layers of organic solar cells, where various preparation techniques have been used, have been analysed and compared to device behaviour. In addition, materials with predefined structures, including contrast enhancing features, have been studied and double tilt data collection has been employed to improve reconstructions. Small changes in preparation procedures may lead to large differences in morphology and device performance, and the results also indicate a complex relation between these.
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| 3. |
- Asplund, Maria, 1978-, et al.
(författare)
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Composite biomolecule/PEDOT materials for neural electrodes
- 2008
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Ingår i: Biointerphases. - NY : American Institute of Physics. - 1559-4106 .- 1934-8630. ; 3:3, s. 83-93
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Tidskriftsartikel (refereegranskat)abstract
- Electrodes intended for neural communication must be designed to meet boththe electrochemical and biological requirements essential for long term functionality. Metallic electrode materials have been found inadequate to meet theserequirements and therefore conducting polymers for neural electrodes have emergedas a field of interest. One clear advantage with polymerelectrodes is the possibility to tailor the material to haveoptimal biomechanical and chemical properties for certain applications. To identifyand evaluate new materials for neural communication electrodes, three chargedbiomolecules, fibrinogen, hyaluronic acid (HA), and heparin are used ascounterions in the electrochemical polymerization of poly(3,4-ethylenedioxythiophene) (PEDOT). The resultingmaterial is evaluated electrochemically and the amount of exposed biomoleculeon the surface is quantified. PEDOT:biomolecule surfaces are also studiedwith static contact angle measurements as well as scanning electronmicroscopy and compared to surfaces of PEDOT electrochemically deposited withsurfactant counterion polystyrene sulphonate (PSS). Electrochemical measurements show that PEDOT:heparinand PEDOT:HA, both have the electrochemical properties required for neuralelectrodes, and PEDOT:heparin also compares well to PEDOT:PSS. PEDOT:fibrinogen isfound less suitable as neural electrode material.
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| 4. |
- Asplund, M, et al.
(författare)
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Toxicity evaluation of PEDOT/biomolecular composites intended for neural communication electrodes
- 2009
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Ingår i: BIOMEDICAL MATERIALS. - : IOP Publishing. - 1748-6041 .- 1748-605X. ; 4:4, s. 045009-
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Tidskriftsartikel (refereegranskat)abstract
- Electrodes coated with the conducting polymer poly(3,4-ethylene dioxythiophene) (PEDOT) possess attractive electrochemical properties for stimulation or recording in the nervous system. Biomolecules, added as counter ions in electropolymerization, could further improve the biomaterial properties, eliminating the need for surfactant counter ions in the process. Such PEDOT/biomolecular composites, using heparin or hyaluronic acid, have previously been investigated electrochemically. In the present study, their biocompatibility is evaluated. An agarose overlay assay using L929 fibroblasts, and elution and direct contact tests on human neuroblastoma SH-SY5Y cells are applied to investigate cytotoxicity in vitro. PEDOT: heparin was further evaluated in vivo through polymer-coated implants in rodent cortex. No cytotoxic response was seen to any of the PEDOT materials tested. The examination of cortical tissue exposed to polymer-coated implants showed extensive glial scarring irrespective of implant material (Pt:polymer or Pt). However, quantification of immunological response, through distance measurements from implant site to closest neuron and counting of ED1+ cell density around implant, was comparable to those of platinum controls. These results indicate that PEDOT: heparin surfaces were non-cytotoxic and show no marked difference in immunological response in cortical tissue compared to pure platinum controls.
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| 5. |
- Barrau, Sophie, et al.
(författare)
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Nanomorphology of Bulk Heterojunction Organic Solar Cells in 2D and 3D Correlated to Photovoltaic Performance
- 2009
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Ingår i: Macromolecules. - : American Chemical Society (ACS). - 0024-9297 .- 1520-5835. ; 42:13, s. 4646-4650
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Tidskriftsartikel (refereegranskat)abstract
- Control of the nanoscale morphology of the donor-acceptor material blends inorganic solar Cells is critical for optimizing the photovoltaic performances. The influence of intrinsic (acceptor materials) and extrinsic (donor:acceptor weight ratio, substrate, solvent) parameters was investigated, by atomic force microscopy (AFM) and electron tomography (ET), on the nanoscale phase separation of blends of a low-band-gap alternating polyfluorene copolymers (APFO-Green9) with [6,6]-phenyl-C-71-butyric acid methyl ester ([70]PCBM). The photovoltaic performances display an optimal efficiency for the device elaborated with a 1:3 APFO-Green polymer:[70][PCBM weight ratio and spin-coated from chloroform solution. The associated active layer morphology presents small phase-separated domains which is a good balance between as a large interfacial donor-acceptor area and Continuous paths of the donor and acceptor phases to the electrodes.
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| 6. |
- Björk, Per, et al.
(författare)
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Biomolecular nanowires decorated by organic electronic polymers
- 2010
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Ingår i: JOURNAL OF MATERIALS CHEMISTRY. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 20:12, s. 2269-2276
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate the shaping and forming of organic electronic polymers into designer nanostructures using biomacromolecules. In order to create nanowires, nanohelixes and assemblies of these, we coordinate semiconducting or metallic polymers to biomolecular polymers in the form of DNA and misfolded proteins. Optoelectronic and electrochemical devices utilizing these shaped materials are discussed.
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| 7. |
- Liu, Lianlian, 1988-, et al.
(författare)
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Black Charcoal for Green and Scalable Wooden Electrodes for Supercapabatteries
- 2022
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Ingår i: Energy Technology. - : Wiley-VCH Verlag GMBH. - 2194-4288 .- 2194-4296. ; 10:3
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Tidskriftsartikel (refereegranskat)abstract
- A green, though black, sustainable and low-cost carbon material-charcoal produced from wood-is developed for electricity storage. Charcoal electrodes are fabricated by ball-milling charcoal and adding protein nanofibril binders. The charcoal electrode presents a capacitance of 360 F g(-1) and a conductivity of 0.2 S m(-1). A pair of redox peaks is observed in the cyclic voltammetry and assigned to originate from quinone groups. Compared with other wooden electrodes, these charcoal electrodes display better cycling stability with 88% capacity retention after 1000 cycles. Their discharge capacity is 2.5 times that of lignosulfonate/graphite hybrid electrodes.
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| 8. |
- Müller, Christian, et al.
(författare)
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Functionalisation of recombinant spider silk with conjugated polyelectrolytes
- 2011
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Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry. - 0959-9428 .- 1364-5501. ; 21:9, s. 2909-2915
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Tidskriftsartikel (refereegranskat)abstract
- Conjugated polyelectrolytes are demonstrated to permit facile staining of recombinant spider silk fibres. We find that the polyelectrolyte concentration and pH of the staining solution as well as the incubation temperature strongly influence the efficiency of this self-assembly process, which appears to be principally mediated through favourable electrostatic interactions. Thus, depending on the choice of staining conditions as well as the polyelectrolyte, electrically conductive or photoluminescent recombinant silk fibres could be produced. In addition, staining of natural Bombyx mori silk is established, which emphasises the versatility of the here advanced approach to functionalise silk-based materials.
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| 9. |
- Teixeira, A.I., et al.
(författare)
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The promotion of neuronal maturation on soft substrates
- 2009
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Ingår i: Biomaterials. - : Elsevier BV. - 0142-9612 .- 1878-5905. ; 30:27, s. 4567-4572
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Tidskriftsartikel (refereegranskat)abstract
- Microenvironmental mechanical properties of stem cell niches vary across tissues and developmental stages. Accumulating evidence suggests that matching substrate elasticity with in vivo tissue elasticity facilitates stem cell differentiation. However, it has not been established whether substrate elasticity can control the maturation stage of cells generated by stem cell differentiation. Here we show that soft substrates with elasticities commensurable to the elasticity of the brain promote the maturation of neural stem cell-derived neurons. In the absence of added growth factors, neurons differentiated on soft substrates displayed long neurites and presynaptic terminals, contrasting with the bipolar immature morphology of neurons differentiated on stiff substrates. Further, soft substrates supported an increase in astrocytic differentiation. However, stiffness cues could not override the dependency of astrocytic differentiation on Notch signaling. These results demonstrate that substrate elasticity per se can drive neuronal maturation thus defining a crucial parameter in neuronal differentiation of stem cells.
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| 10. |
- Thaning, Elin M., et al.
(författare)
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Stability of Poly(3,4-ethylene dioxythiophene) Materials Intended for Implants
- 2010
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Ingår i: Journal of Biomedical Materials Research - Part B Applied Biomaterials. - : Wiley. - 1552-4973 .- 1552-4981. ; 93B:2, s. 407-415
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Tidskriftsartikel (refereegranskat)abstract
- This study presents experiments designed to study the stability of the conducting polymer poly(3,4-ethylene dioxythiophene) (PEDOT), under simulated physiological conditions using phosphate-buffered saline (PBS) and hydrogen peroxide (H2O2) (0 01M) at 37 degrees C over a 5- to 6-week period Voltage pulsing in PBS was used as an additional test environment The influence of switching the counter ion used in electropolymerization from polystyrene sulphonate (PSS) to heparin was investigated Absorbance spectroscopy and cyclic voltammetry were used to evaluate the material properties Most of the samples in H2O2 lost both electroactivity and optical absorbance within the study period, but PEDOT.PSS was found slightly more stable than PEDOT heparin. Polymers were relatively stable in PBS throughout the study period, with around 80% of electroactivity remaining after 5 weeks, disregarding delamination, which was a significant problem especially for polymer on indium tin oxide substrates Voltage pulsing in PBS did not increase degradation. The counter ion influenced the time course of degradation in Oxidizing agents.
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