| 1. |
- Arja, Katriann, et al.
(författare)
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Enhanced Fluorescent Assignment of Protein Aggregates by an Oligothiophene-Porphyrin-Based Amyloid Ligand
- 2013
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Ingår i: Macromolecular rapid communications. - : Wiley-VCH Verlag. - 1022-1336 .- 1521-3927. ; 34:9, s. 723-730
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Tidskriftsartikel (refereegranskat)abstract
- Fluorescent probes identifying protein aggregates are of great interest, as deposition of aggregated proteins is associated with many devastating diseases. Here, we report that a fluorescent amyloid ligand composed of two distinct molecular moieties, an amyloidophilic pentameric oligothiophene and a porphyrin, can be utilized for spectral and lifetime imaging assessment of recombinant A 1-42 amyloid fibrils and A deposits in brain tissue sections from a transgenic mouse model with Alzheimers disease pathology. The enhanced spectral range and distinct lifetime diversity of this novel oligothiopheneporphyrin-based ligand allow a more precise assessment of heterogeneous amyloid morphology compared with the corresponding oligothiophene dye.
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| 2. |
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| 3. |
- Cappel, Ute B., et al.
(författare)
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Characterization of the Interface Properties and Processes in Solid State Dye-Sensitized Solar Cells Employing a Perylene Sensitizer
- 2011
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Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 115:10, s. 4345-4358
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Tidskriftsartikel (refereegranskat)abstract
- We recently reported on a perylene sensitizer, ID176, which performs much better in solid state dye-sensitized solar cells than in those using liquid electrolytes with iodide/tri-iodide as the redox couple (J. Phys. Chem. C2009, 113, 14595-14597). Here, we present a characterization of the sensitizer and of the TiO2/dye interface by UV-visible absorption and fluorescence spectroscopy, spectroelectrochemistry, photoelectron spectroscopy, electroabsorption spectroscopy, photoinduced absorption spectroscopy, and femtosecond transient absorption measurements. We report that the absorption spectrum of the sensitizer is red-shifted by addition of lithium ions to the surface due to a downward shift of the excited state level of the sensitizer, which is of the same order of magnitude as the downward shift of the titanium dioxide conduction band edge. Results from photoelectron spectroscopy and electrochemistry suggest that the excited state is largely located below the conduction band edge of TiO2 but that there are states in the band gap of TiO2 which might be available for photoinduced electron injection. The sensitizer was able to efficiently inject into TiO2, when a lithium salt was present on the surface, while injection was much less effective in the absence of lithium ions or in the presence of solvent. In the presence of the hole conductor 2,2-,7,7-tetrakis-(N,N-di-p-methoxyphenyl-amine)-9,9-spirobifluorene (spiro-MeOTAD) and LiTFSI, charge separation was monitored by the emergence of a Stark shift of the dye in transient absorption spectra, and both injection and regeneration appear to be completed within 1 ps. Regeneration by spiro-MeOTAD is therefore several orders of magnitude faster than regeneration by iodide, and ID176 can even be photoreduced by spiro-MeOTAD.
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| 4. |
- Gibson, Elizabeth A., et al.
(författare)
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Cobalt Polypyridyl-Based Electrolytes for p-Type Dye-Sensitized Solar Cells
- 2011
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Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 115:19, s. 9772-9779
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Tidskriftsartikel (refereegranskat)abstract
- A series of polypyridyl cobalt complexes with different substituents was applied as redox mediators in p-type dye-sensitized solar cells (p-DSCs), consisting of mesoporous NiO sensitized with a perylenemonoimide naphthalenediimide (PMI-NDI) dyad. The photocurrent and photovoltages of the devices were found to depend on the steric bulk of the redox species rather than their electrochemical potential. Bulky substituents were found to slow the detrimental charge recombination reactions between holes in the NiO semiconductor and the reduced form of the redox couple. The open-circuit potential (V-OC) of each of the devices was superior to the equivalent PMI-NDIsensitized p-DSCs containing the triiodide/iodide redox couple.
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| 5. |
- Le Pleux, Loic, et al.
(författare)
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Synthesis, photophysical and photovoltaic investigations of acceptor-functionalized perylene monoimide dyes for nickel oxide p-type dye-sensitized solar cells
- 2011
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Ingår i: ENERGY & ENVIRONMENTAL SCIENCE. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 4:6, s. 2075-2084
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Tidskriftsartikel (refereegranskat)abstract
- We report on the synthesis, electrochemical, photophysical, and photovoltaic properties of a series of three organic dyads comprising a perylene monoimide (PMI) dye connected to a naphthalene diimide (NDI) or a fullerene (C-60) for application in dye-sensitized solar cells (DSCs) with nanocrystalline NiO electrodes. It was found that the secondary electron acceptor (NDI or C-60) in all the three dyads extends the charge separated state lifetime by about five orders of magnitude compared to the respective parent PMI dye. Nanosecond pump-probe experiments of the NiO/dyads in the presence of the electrolyte show that the reduction of triiodide by the secondary electron acceptor is slow in all the dyads, which we ascribe to a weak driving force for this reaction. This reaction is significantly faster with the cobalt electrolyte (tris(4,4'-di-tert-butyl-2,2'-bipyridine)cobalt(II/III)), whose driving force is larger; however, its reaction with the reduced dyads is still rather slow. We demonstrate that the larger photovoltage observed with the cobalt electrolyte (V-OC = 285 mV) relative to the iodide electrolyte (V-OC = 120 mV) is due to a decrease in the dark current for the former owing to slower interfacial electron transfer of the reduced mediator with the injected holes into the NiO electrode. In terms of photovoltaic performances, the most efficient dyad is the system in which the NDI is directly connected to the PMI (eta = 0.14% under AM 1.5 with the cobalt electrolyte), but the dyad containing the fullerene acceptor exhibits the highest IPCE and the highest short circuit current density (IPCE = 57%, J(SC) = 1.88 mA cm(-2)) with the iodide electrolyte. The latter performances are attributed to the slightly stronger reducing power of C-60 relative to NDI, which favours the reduction of the mediator in the electrolyte.
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| 6. |
- Nyström, Sofie, et al.
(författare)
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Evidence for Age-Dependent in Vivo Conformational Rearrangement within A beta Amyloid Deposits
- 2013
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Ingår i: ACS Chemical Biology. - : American Chemical Society. - 1554-8929 .- 1554-8937. ; 8:6, s. 1128-1133
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Tidskriftsartikel (refereegranskat)abstract
- Deposition of aggregated A beta peptide in the brain is one of the major hallmarks of Alzheimers disease. Using a combination of two structurally different, but related, hypersensitive fluorescent amyloid markers, LCOs, reporting on separate ultrastructural elements, we show that conformational rearrangement occurs within A beta plaques of transgenic mouse models as the animals age. This important mechanistic insight should aid the design and evaluation of experiments currently using plaque load as readout.
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| 7. |
- Odobel, Fabrice, et al.
(författare)
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Recent advances and future directions to optimize the performances of p-type dye-sensitized solar cells
- 2012
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Ingår i: Coordination chemistry reviews. - : Elsevier BV. - 0010-8545 .- 1873-3840. ; 256:21-22, s. 2414-2423
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Forskningsöversikt (refereegranskat)abstract
- This review provides a summary of the most important developments in the field of solar cells based on the sensitization of p-type semiconductors, such as NiO, and identifies the future challenges and opportunities to enhance their overall performance. In particular, the main factors responsible for the low open-circuit voltage, short circuit photocurrent and fill factor are discussed in detail.
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| 8. |
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| 9. |
- Sjöberg, Ronald, et al.
(författare)
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Biosensor based protein profiling on reverse phase serum microarray
- 2012
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Ingår i: Journal of Proteomics and Bioinformatics. - : OMICS Publishing Group. - 0974-276X. ; 5:8, s. 185-189
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Tidskriftsartikel (refereegranskat)abstract
- The reverse phase serum microarray format enables multi-parallel and simultaneous analysis of literally thousands of samples, a feature which is of uttermost importance for protein profiling of clinical samples. We have here screened 2400 serum samples for their potential IgA deficiency by using a fluorescence based reverse phase serum microarray platform and a biosensor based label-free microarray platform for verification and also compared our microarray-results to clinical routine ELISA. We have been able to identify possible IgA-deficiencies and to show the suitability of our microarray-platforms for large-scale screening of clinical serum samples. The two microarray methods show reproducibility and correlation towards each other and low variation between replicates within each platform. Both of the microarray platforms show less agreement towards ELISA. The fluorescence based microarray method has been shown to be applicable for large-scale screening of clinically important serum samples for detection of possibly IgA-deficient patients. Furthermore, it was found that the microarray based biosensor method could be used for determining the relative differences in concentration of IgA between the samples.
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| 10. |
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