| 1. |
- Aasmundtveit, K.E., et al.
(författare)
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Structural ordering in phenyl-substituted polythiophenes
- 2000
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Ingår i: Macromolecules. - : American Chemical Society (ACS). - 0024-9297 .- 1520-5835. ; 33:15, s. 5481-5489
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Tidskriftsartikel (refereegranskat)abstract
- Various substituted poly(phenylthiophene)s have been studied by X-ray diffraction. They are semicrystalline, with very different degrees of crystallinity. Those with para-substituted phenyl groups have a low degree of crystallinity, whereas those with ortho-substituted phenyl groups are more crystalline. The most crystalline materials in this study have two equally long substituents on the phenyl ring, one at the ortho position and the other at the ortho or meta position on the opposite side of the phenyl ring. Poly(3-(2,5-dioctylphenyl)thiophene) (PDOPT) was most thoroughly studied, and a structural model is proposed. The structure of PDOPT is quite different from previously studied substituted polythiophenes in that the octyl side chains are directed normal to the thiophene planes. In this way, the conjugated polymer chains are kept separated from each other. Solution-cast and spin-cast PDOPT films are anisotropic, with the octyl side chains oriented normal to the film surface in both cases. This is contrary to the situation for poly(3-alkylthiophene)s, where solution-cast and spin-cast films orient in different ways.
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| 2. |
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| 3. |
- Chen, LC, et al.
(författare)
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Excitation transfer in polymer photodiodes for enhanced quantum efficiency
- 2000
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Ingår i: Advanced Materials. - 0935-9648 .- 1521-4095. ; 12:15, s. 1110-
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Tidskriftsartikel (refereegranskat)abstract
- The realization of polymer solar cells is the driving force behind this research. In an idea inspired by photosynthesis, the authors have constructed efficient bilayer photodiodes by a well-chosen combination of conjugated polymers (see Figure) in the donor layer. Forster energy transfer within the donor layer allows the absorbed light to be channeled to the C-60 acceptor layer, improving the total photoconversion of the blend device.
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| 4. |
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| 5. |
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| 6. |
- Inganäs, Olle, et al.
(författare)
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Low bandgap alternating polyfluorene copolymers in plastic photodiodes and solar cells
- 2004
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Ingår i: Applied Physics A. - : Springer Science and Business Media LLC. - 0947-8396 .- 1432-0630. ; 79:1, s. 31-35
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Tidskriftsartikel (refereegranskat)abstract
- We report a comparative study of plastic photodiodes using four different copolymers of fluorene, with a variation of alkyl side chain length and chemical structure. Photodiode materials are formed by blending the polymers with a fullerene derivative and spincoating the blend solution. A photovoltage of 1 V is obtained in devices, where the anode is a doped polymer and the cathode is LiF/Al. Monochromatic quantum efficiencies are better than 40% over most of the absorption range, and under solar light AM 1.5 simulation, we reach energy efficiencies beyond 2%. The high fill factors obtained in some of the devices indicate that these are of interest for more elaborate optimisation. Reasons for the benign electrical transport are discussed. © Springer-Verlag 2004.
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| 7. |
- Jacobson, S., et al.
(författare)
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Alloreactivity but Failure to Reject Human Islet Transplants by Humanized Balb/c/Rag2(-/-)gc(-/-) Mice
- 2010
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Ingår i: Scandinavian Journal of Immunology. - : Wiley. - 0300-9475 .- 1365-3083. ; 71:2, s. 83-90
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Tidskriftsartikel (refereegranskat)abstract
- A human islet transplant can cure patients with type 1 diabetes. A drawback of islet transplantation is the life-long immunosuppressive medication, often associated with severe side effects. Moreover, in spite of the immunosuppressive therapy, islets are lost in the majority of transplanted patients over time. An improved small animal model for studies on human islet allograft rejection mechanisms and the development of new measures for its prevention is clearly warranted. Here, we evaluated the potential of Balb/cRag2(-/-)gamma c(-/-) mice carrying a human-like immune system (so-called humanized mice) as a tool for studies on the rejection of transplanted human islets. Human T cells from Balb/cRag2(-/-)gamma c(-/-) mice, which as neonates had been transplanted with CD34(+) human cord blood haematopoietic stem cells (HIS mice), proliferated in response to allogeneic human dendritic cells, but failed to reject a human islet allograft transplanted to the renal subcapsular space as assessed by immunohistochemistry and analysis of human serum C-peptide levels. Histological analysis revealed that few if any T cells had migrated to the grafted tissue. These observations question the usefulness of the HIS mouse model for studies on human islet allograft rejection mechanisms and highlight the need for further improvements.
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| 8. |
- Johansson, Tomas, et al.
(författare)
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Electrochemical bandgaps of substituted polythiophenes
- 2003
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Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 13:6, s. 1316-1323
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Tidskriftsartikel (refereegranskat)abstract
- The electrochemical bandgaps for different soluble substituted polythiophenes have been measured by cyclic voltammetry. The effect of substituents on the oxidation/reduction potentials is discussed. Bandgaps obtained by cyclic voltammetry have been found to be in general higher than optical bandgaps. Among regioregular polymers substituted with a phenyl group at position 3 of the thiophene ring, examples are found that give very symmetric voltammograms. Rationalization for this behaviour is discussed from a conformational point of view.
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| 9. |
- Jonforsen, M., et al.
(författare)
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Photodiodes made from poly(pyridopyrazine vinylene) : polythiophene blends
- 2001
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Ingår i: Synthetic metals. - 0379-6779 .- 1879-3290. ; 119:1-3, s. 185-186
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Tidskriftsartikel (refereegranskat)abstract
- A PPV-type polymer with the pyridopyrazine heterocycle (EHH-PPyPzV) has been synthesised and found to have high electron affinity according to electrochemical measurements. When used as the electron accepting material in single-layer-photodiodes, with a thiophene copolymer (PEOPT-co-PAAPT) as the electron donating material, IPCE (incident photon to current conversion efficiency) up to 1% was measured. Atomic force microscopy was used to analyse the blend morphology in the devices.
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| 10. |
- Lindgren, S., et al.
(författare)
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Laser flip-chip mounting for passive alignment and high-frequency modulation
- 1996
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Ingår i: Optical Communication, 1996. ECOC ’96. 22nd European Conference on. ; , s. 103-106
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Konferensbidrag (refereegranskat)abstract
- We have developed a silicon motherboard for flip-chip mounting of lasers in a way that is compatible with high-frequency modulation (24 GHz) and which allows passive alignment of the lasers to single-mode fibres.
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