| 11. |
- Hamedi, Mahiar, et al.
(författare)
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Fiber-Embedded Electrolyte-Gated Field-Effect Transistors for e-Textiles
- 2009
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Ingår i: Advanced Materials. - : Wiley. - 0935-9648 .- 1521-4095. ; 21:5, s. 573-577
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Tidskriftsartikel (refereegranskat)abstract
- Electrolyte-gate organic field-effect transistors embedded at the junction of textile microfibers are demonstrated. The fiber transistor operates below I V and delivers large current densities. The transience of the organic thin-film transistors current and the impedance spectroscopy measurements reveal that the channel is formed in two steps.
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| 12. |
- Hamedi, Mahiar, et al.
(författare)
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Towards woven logic from organic electronic fibres
- 2007
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Ingår i: Nature Materials. - : Springer Science and Business Media LLC. - 1476-1122 .- 1476-4660. ; 6:5, s. 357-362
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Tidskriftsartikel (refereegranskat)abstract
- The use of organic polymers for electronic functions is mainly motivated by the low-end applications, where low cost rather than advanced performance is a driving force. Materials and processing methods must allow for cheap production. Printing of electronics using inkjets1 or classical printing methods has considerable potential to deliver this. Another technology that has been around for millennia is weaving using fibres. Integration of electronic functions within fabrics, with production methods fully compatible with textiles, is therefore of current interest, to enhance performance and extend functions of textiles2. Standard polymer field-effect transistors require well defined insulator thickness and high voltage3, so they have limited suitability for electronic textiles. Here we report a novel approach through the construction of wire electrochemical transistor (WECT) devices, and show that textile monofilaments with 10–100 m diameters can be coated with continuous thin films of the conducting polythiophene poly(3,4-ethylenedioxythiophene), and used to create micro-scale WECTs on single fibres. We also demonstrate inverters and multiplexers for digital logic. This opens an avenue for three-dimensional polymer micro-electronics, where large-scale circuits can be designed and integrated directly into the three-dimensional structure of woven fibres.
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| 13. |
- Hevekerl, Heike, 1982-, et al.
(författare)
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Dark states in ionic oligothiophene bioprobes-evidence from fluorescence correlation spectroscopy and dynamic light scattering
- 2014
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Ingår i: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-6106 .- 1520-5207. ; 118:22, s. 5924--5933
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Tidskriftsartikel (refereegranskat)abstract
- Luminescent conjugated polyelectrolytes (LCPs) can upon interaction with biological macromolecules change their luminescent properties, and thereby serve as conformation- and interaction-sensitive biomolecular probes. However, to exploit this in a more quantitative manner, there is a need to better understand the photophysical processes involved. We report studies of the conjugated pentameric oligothiophene, derivative p-FTAA, which changes optical properties with different p-FTAA concentrations in aqueous buffers, and in a pH and oxygen saturation dependent manner. Using dynamic light scattering, luminescence spectroscopy and fluorescence correlation spectroscopy, we find evidence for a monomer dimer equilibrium, for the formation of large clusters of p-FTAA in aqueous environment, and can couple aggregation to changed emission properties of oligothiophenes. In addition, we observe the presence of at least two dark transient states, one presumably being a triplet state. Oxygen was found to statically quench the p-FTAA fluorescence but also to promote molecular fluorescence by quenching dark transient states of the p-FTAA molecules. Taken together, this study provides knowledge of fluorescence and photophysical features essential for applying p-FTAA and other oligothiophene derivatives for diagnostic purposes, including detection and staining of amyloid aggregates.
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| 14. |
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| 15. |
- Karlsson, Roger, et al.
(författare)
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Iron-Catalyzed Polymerization of Alkoxysulfonate-Functionalized 3,4-Ethylenedioxythiophene Gives Water-Soluble Poly(3,4-ethylenedioxythiophene) of High Conductivity
- 2009
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Ingår i: Chemistry of Materials. - : American Chemical Society (ACS). - 0897-4756 .- 1520-5002. ; 21:9, s. 1815-1821
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Tidskriftsartikel (refereegranskat)abstract
- Chemical polymerization of a 3,4-ethylenedioxythiophene derivative bearing a sulfonate group (EDOTS) is reported. The polymer, PEDOT-S, is fully water-soluble and has been produced by polymerizing EDOT-S in water, using Na2S2O8 and a catalytic amount of FeCl 3. Elemental analysis and XPS measurements indicate that PEDOT-S is a material with a substantial degree of self-doping, but also contains free sulfate ions as charge-balancing counterions of the oxidized polymer. Apart from selfdoping PEDOT-S, the side chains enable full water solubility of the material; DLS studies show an average cluster size of only 2 nm. Importantly, the solvation properties of the PEDOT-S are reflected in spin-coated films, which show a surface roughness of 1.2 nm and good conductivity (12 S/cm) in ambient conditions. The electro-optical properties of this material are shown with cyclic voltammetry and spectroelectrochemical experiment reveals an electrochromic contrast (̃48% at λmax ) 606 nm).
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| 16. |
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| 17. |
- 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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| 18. |
- Müller, Christian, et al.
(författare)
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Woven Electrochemical Transistors on Silk Fibers
- 2011
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Ingår i: ADVANCED MATERIALS. - : John Wiley and Sons, Ltd. - 0935-9648 .- 1521-4095. ; 23:7, s. 898-
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Tidskriftsartikel (refereegranskat)abstract
- Woven electrochemical transistors on silk fibers from the silkworm Bombyx mori are demonstrated. This is achieved with carefully chosen electrolyte chemistry: electrically conducting silk fibers are produced by dyeing silk fibers with a conjugated polyelectrolyte and gating is accomplished by use of an electrolyte mixture composed of imidazolium-based ionic liquids.
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| 19. |
- Musumeci, Chiara, et al.
(författare)
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Multiparameter investigation of bulk heterojunction organic photovoltaics
- 2017
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Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 7:73, s. 46313-46320
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Tidskriftsartikel (refereegranskat)abstract
- A key parameter to improve the performance of organic solar cells is the optimization of electronic phenomena at donor-acceptor interfaces through the optimization of the morphology of the bulk heterojunction. The correlative mapping of morphological, electrical and mechanical properties at the nanoscale by advanced scanning probe microscopy techniques allows for a detailed characterization of the local structure-property relationships in bulk heterojunctions solar cells. Unique opportunities for the investigation of these photoactive films are shown here, ultimately suggesting fundamental guidelines toward the accurate engineering of these materials at the nanoscale.
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| 20. |
- 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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