| 1. |
- Andersson, Mattias, et al.
(författare)
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Intrinsic and extrinsic influences on the temperature dependence of mobility in conjugated polymers
- 2008
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Ingår i: Organic electronics. - : Elsevier. - 1566-1199 .- 1878-5530. ; 9:5, s. 569-574
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Tidskriftsartikel (refereegranskat)abstract
- The temperature dependence of charge carrier mobility in conjugated polymers and their blends with fullerenes is investigated with different electrical methods, through field effect transistor (FET), space charge limited current (SCLC) and charge extraction (CELIV) measurements. Simple models, such as the Gaussian disorder model (GDM), are shown to accurately predict the temperature behavior, and a good correlation between the different measurement methods is obtained. Inconsistent charge carrier concentrations in the modeling are explained through intrinsic non-equilibrium effects, and are responsible for the limited applicability of existing numerical models. A severe extrinsic influence from water in FETs with a hydrophilic insulator interface is also demonstrated. The presence of water leads to a significant overestimate of the disorder in the materials from measurements close to room temperature and erratic behavior in the 150-350 K range. To circumvent this problem it is shown to be necessary to measure under ultra high vacuum (UHV) conditions. © 2008 Elsevier B.V. All rights reserved.
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| 2. |
- Chen, Miaoxiang, 1962-, et al.
(författare)
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High carrier mobility in low band gap polymer-based field-effect transistors
- 2005
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 87:25, s. 252105-1-252105-3
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Tidskriftsartikel (refereegranskat)abstract
- A conjugated polymer with a low band gap of 1.21 eV, i.e., absorbing infrared light, is demonstrated as active material in field-effect transistors (FETs). The material consists of alternating fluorene units and low band gap segments with electron donor-acceptor-donor units composed of two electron-donating thiophene rings attached on both sides of a thiadiazolo-quinoxaline electron-acceptor group. The polymer is solution-processable and air-stable; the resulting FETs exhibit typical p-channel characteristics and field-effect mobility of 0.03 cm2 V−1 s−1.
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| 3. |
- 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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| 4. |
- Wang, Xiangjun, 1964-, et al.
(författare)
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Dynamic Control of Surface Energy and Topography of Microstructured Conducting Polymer Films
- 2008
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 24, s. 5942-5948
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Tidskriftsartikel (refereegranskat)abstract
- Microstructured polymer surfaces, including conducting and insulating polymers, have been prepared to achieve electrochemical control of the surface energy and topography. The reported surface switches include pillar- and mesh-like surface patterns of polypyrrole (PPy), poly(3,4-ethylene-dioxythiophene) (PEDOT), and photoresists. The structures have been evaluated by contact angle measurements and optical and scanning electron microscopy to determine the surfaces characteristics. These microstructured polymer surface switches can be electrochemically modified from dewetting to wetting conditions, with a maximum associated change of the water contact angle from 129° to 44°. This contact angle switching was observed for samples in which dynamic control of the surface topography and surface tension was coupled. Control of topography was achieved with a dynamic height-switching range of more than 3 ìm. In addition, dynamic control of anisotropic wetting is reported. Our experiments were carried out under conditions that are suitable for a biointerface, implying potential application in biotechnology and cell science. In particular, switching of the energy, chemistry, and topography of the surface, along with their associated orientation, are interesting features for dynamic (electronic) control of the seeding and proliferation for living cells. The technology reported promises for electronically controlled cell-growth within Petri dishes, well plates, and other cell-hosting tools.
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