| 1. |
- Mathijssen, Simon G. J., et al.
(författare)
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Charge trapping at the dielectric of organic transistors visualized in real time and space
- 2008
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Ingår i: Advanced Materials. - : Wiley-VCH Verlag. - 0935-9648 .- 1521-4095. ; 20:5, s. 975-
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Tidskriftsartikel (refereegranskat)abstract
- Scanning Kelvin probe microscopy demonstrates that water-induced charge trapping at the SiO2 dielectric visualized in real time and space - is responsible for the commonly observed gate-bias-induced threshold-voltage shift in organic field-effect transistors. When a bias is applied to the electrodes, charges are injected onto the SiO2 (see background of the figure). When the contacts are grounded, the charges are released again (foreground picture).
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| 2. |
- Mathijssen, Simon G. J., et al.
(författare)
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Manipulating the local light emission in organic light-emitting diodes by using patterned self-assembled monolayers
- 2008
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Ingår i: Advanced Materials. - : Wiley-VCH Verlag. - 0935-9648 .- 1521-4095. ; 20:14, s. 2703-
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Tidskriftsartikel (refereegranskat)abstract
- Patterned organic light-emitting diodes are fabricated by using microcontactDrinted self-assembled monolayers on a gold anode (see background figure). Molecules with dipole moments in opposite directions result in an increase or a decrease of the local work function (foreground picture), providing a direct handle on charge injection and enabling local modification of the light emission
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| 3. |
- Mathijssen, Simon G. J., et al.
(författare)
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Monolayer coverage and channel length set the mobility in self-assembled monolayer field-effect transistors
- 2009
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Ingår i: Nature Nanotechnology. - : Nature Publishing Group. - 1748-3387 .- 1748-3395. ; 4:10, s. 674-680
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Tidskriftsartikel (refereegranskat)abstract
- The mobility of self-assembled monolayer field-effect transistors (SAMFETs) traditionally decreases dramatically with increasing channel length. Recently, however, SAMFETs using liquid-crystalline molecules have been shown to have bulk-like mobilities that are virtually independent of channel length. Here, we reconcile these scaling relations by showing that the mobility in liquid crystalline SAMFETs depends exponentially on the channel length only when the monalayer is incomplete. We explain this dependence both numerically and analytically, and show that charge transport is not affected by carrier injection, grain boundaries or conducting island size. At partial coverage, that is when the monolayer is incomplete, liquid-crystalline SAMFETs thus form a unique model system to study size-dependent conductance originating from charge percolation in two dimensions.
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| 4. |
- Smits, Edsger C. P., et al.
(författare)
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Bottom-up organic integrated circuits
- 2008
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Ingår i: Nature. - : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; 455:7215, s. 956-959
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Tidskriftsartikel (refereegranskat)abstract
- Self- assembly - the autonomous organization of components into patterns and structures(1) - is a promising technology for the mass production of organic electronics. Making integrated circuits using a bottom- up approach involving self- assembling molecules was proposed(2) in the 1970s. The basic building block of such an integrated circuit is the self- assembled- monolayer field- effect transistor ( SAMFET), where the semiconductor is a monolayer spontaneously formed on the gate dielectric. In the SAMFETs fabricated so far, current modulation has only been observed in submicrometre channels(3-5), the lack of efficient charge transport in longer channels being due to defects and the limited intermolecular pi-pi coupling between the molecules in the self-assembled monolayers. Low field- effect carrier mobility, low yield and poor reproducibility have prohibited the realization of bottom- up integrated circuits. Here we demonstrate SAMFETs with long- range intermolecular pi - pi coupling in the monolayer. We achieve dense packing by using liquid- crystalline molecules consisting of a pi- conjugated mesogenic core separated by a long aliphatic chain from a monofunctionalized anchor group. The resulting SAMFETs exhibit a bulk- like carrier mobility, large current modulation and high reproducibility. As a first step towards functional circuits, we combine the SAMFETs into logic gates as inverters; the small parameter spread then allows us to combine the inverters into ring oscillators. We demonstrate real logic functionality by constructing a 15- bit code generator in which hundreds of SAMFETs are addressed simultaneously. Bridging the gap between discrete monolayer transistors and functional self-assembled integrated circuits puts bottom- up electronics in a new perspective.
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