| 1. |
- Blaudeck, Thomas, et al.
(författare)
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Simplified Large-Area Manufacturing of Organic Electrochemical Transistors Combining Printing and a Self-Aligning Laser Ablation Step
- 2012
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Ingår i: Advanced Functional Materials. - : Wiley-VCH Verlag Berlin. - 1616-301X .- 1616-3028. ; 22:14, s. 2939-2948
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Tidskriftsartikel (refereegranskat)abstract
- A hybrid manufacturing approach for organic electrochemical transistors (OECTs) on flexible substrates is reported. The technology is based on conventional and digital printing (screen and inkjet printing), laser processing, and post-press technologies. A careful selection of the conductive, dielectric, and semiconductor materials with respect to their optical properties enables a self-aligning pattern formation which results in a significant reduction of the usual registration problems during manufacturing. For the prototype OECTs, based on this technology, on/off ratios up to 600 and switching times of 100 milliseconds at gate voltages in the range of 1 V were obtained.
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| 2. |
- Jauhiainen, Jyrki, et al.
(författare)
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Reviews and syntheses: Greenhouse gas exchange data from drained organic forest soils-A review of current approaches and recommendations for future research
- 2019
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Ingår i: Biogeosciences. - : Copernicus GmbH. - 1726-4170 .- 1726-4189. ; 16:23, s. 4687-4703
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Tidskriftsartikel (refereegranskat)abstract
- © Author(s) 2019. Drained organic forest soils in boreal and temperate climate zones are believed to be significant sources of the greenhouse gases (GHGs) carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O), but the annual fluxes are still highly uncertain. Drained organic soils exemplify systems where many studies are still carried out with relatively small resources, several methodologies and manually operated systems, which further involve different options for the detailed design of the measurement and data analysis protocols for deriving the annual flux. It would be beneficial to set certain guidelines for how to measure and report the data, so that data from individual studies could also be used in synthesis work based on data collation and modelling. Such synthesis work is necessary for deciphering general patterns and trends related to, e.g., site types, climate, and management, and the development of corresponding emission factors, i.e. estimates of the net annual soil GHG emission and removal, which can be used in GHG inventories. Development of specific emission factors also sets prerequisites for the background or environmental data to be reported in individual studies. We argue that wide applicability greatly increases the value of individual studies. An overall objective of this paper is to support future monitoring campaigns in obtaining high-value data.We analysed peer-reviewed public cations presenting CO2, CH4 and N2O flux data for drained organic forest soils in boreal and temperate climate zones, focusing on data that have been used, or have the potential to be used, for estimating net annual soil GHG emissions and removals. We evaluated the methods used in data collection and identified major gaps in background or environmental data. Based on these, we formulated recommendations for future research.
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| 3. |
- Laiho, Ari, et al.
(författare)
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Amphiphilic Poly(3-hexylthiophene)-Based Semiconducting Copolymers for Printing of Polyelectrolyte-Gated Organic Field-Effect Transistors
- 2013
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Ingår i: Macromolecules. - : American Chemical Society (ACS). - 0024-9297 .- 1520-5835. ; 46:11, s. 4548-4557
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Tidskriftsartikel (refereegranskat)abstract
- Polyelectrolytes are promising electronically insulating layers for low-voltage organic field effect transistors. However, the polyelectrolyte–semiconductor interface is difficult to manufacture due to challenges in wettability. We introduce an amphiphilic semiconducting copolymer which, when spread as a thin film, can change its surface from hydrophobic to hydrophilic upon exposure to water. This peculiar wettability is exploited in the fabrication of polyelectrolyte-gated field-effect transistors operating below 0.5 V. The prepared amphiphilic semiconducting copolymer is based on a hydrophobic regioregular poly(3-hexylthiophene) (P3HT) covalently linked to a hydrophilic poly(sulfonated)-based random block. Such a copolymer is obtained in a three-step strategy combining Grignard metathesis (GRIM), atom transfer radical polymerization (ATRP) processes, and a postmodification method. The structure of the diblock copolymer was characterized using FT-IR, 1H NMR spectroscopy, and gel permeation chromatography (GPC).
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| 4. |
- Laiho, Ari, et al.
(författare)
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Controlling the dimensionality of charge transport in organic thin-film transistors
- 2011
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 108:37, s. 15069-15073
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Tidskriftsartikel (refereegranskat)abstract
- Electrolyte-gated organic thin-film transistors (OTFTs) can offer a feasible platform for future flexible, large-area and low-cost electronic applications. These transistors can be divided into two groups on the basis of their operation mechanism: (i) field-effect transistors that switch fast but carry much less current than (ii) the electrochemical transistors which, on the contrary, switch slowly. An attractive approach would be to combine the benefits of the field-effect and the electrochemical transistors into one transistor that would both switch fast and carry high current densities. Here we report the development of a polyelectrolyte-gated OTFT based on conjugated polyelectrolytes, and we demonstrate that the OTFTs can be controllably operated either in the field-effect or the electrochemical regime. Moreover, we show that the extent of electrochemical doping can be restricted to a few monolayers of the conjugated polyelectrolyte film, which allows both high current densities and fast switching speeds at the same time. We propose an operation mechanism based on self-doping of the conjugated polyelectrolyte backbone by its ionic side groups.
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| 5. |
- Larsson, Oscar, et al.
(författare)
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Controlling the Dimensionality of Charge Transport in an Organic Electrochemical Transistor by Capacitive Coupling
- 2011
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Ingår i: Advanced Materials. - : Wiley-VCH Verlag Berlin. - 0935-9648 .- 1521-4095. ; 23:41, s. 4764-
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Tidskriftsartikel (refereegranskat)abstract
- The dimensionality of charge transport in an organic electrochemical transistor depends on the degree of advancement of the electrochemical half-reaction at the organic semiconductor/electrolyte interface. A carbon nanotube (CNT) nanoporous gate electrode leads to bulk transport in the semiconductor, while a flat Au gate electrode allows for localizing of the electrochemical oxidation of the semiconducting polymer at the organic semiconductor/electrolyte interface.
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| 6. |
- Larsson, Oscar, 1978-, et al.
(författare)
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Unifying electrochemical and field-effect mechanisms in electrolyte-gated organic field-effect transistors
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The combination of electrolytes and organic semiconductors has opened up new opportunities in photonics1, electronics2 and in energy storage3. In most of these devices, the key mechanisms involve the transport of charge carriers (electrons or ions) across the organic semiconductor-electrolyte interface. The formation of an electric double layer (EDL) at this polarized interface is fuzzier than at a metal-electrolyte interface since weak intermolecular interactions in the organic solid favour the penetration of ions4. An EDL established at the organic semiconductor-electrolyte interface, defined by a sheet of electronic charge carriers and a sheet of ions, has been proposed recently as the basic mechanism for electrolyte-gated organic field-effect transistors (EGOFETs)5, 6. Here, organic thin film transistors are used as a probe to investigate the organic semiconductor-electrolyte interface. We demonstrate that the capacitance value of the gate counter electrode dictates the degree of advancement7 of the electrochemical halfreaction (the extent of the reaction) at this interface. This finding unifies the mechanisms proposed for EGOFETs and organic electrochemical transistors (OECTs); and sets the ground description for an electrochemical half-reaction induced entirely by capacitive coupling.
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| 7. |
- Wang, Xiaodong, et al.
(författare)
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Remanent polarization in a cryptand-polyanion bilayer implemented in an organic field effect transistor
- 2012
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Ingår i: Applied Physics Letters. - : American Institute of Physics (AIP). - 0003-6951 .- 1077-3118. ; 100:2, s. 023305-
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Tidskriftsartikel (refereegranskat)abstract
- We investigate the possibility to maintain an electric polarization in an organic bilayer via ion trapping, i.e., without any external bias. In the cryptand-polyanion bilayer, ions of specific size can be strongly coordinated with organic macrocyclic molecules. Cations move from the polyanion layer to the cryptand layer upon applying a bias and are trapped in this layer. As a result, the voltage dependence of the polarization displays a hysteresis. The bilayer is then advantageously used as an electronic insulating layer in an organic field effect transistor. The ions trapping and de-trapping can be followed by the amplitude of the threshold voltage (V(th)) shift as well as its temporal evolution.
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