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Müller, Christian
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Campoy-Quiles, M., Müller, C., Garriga, M., Wang, E., Inganäs, O. & Alonso, M. I. (2014). On the complex refractive index of polymer:fullerene photovoltaic blends. Paper presented at 6th International Conference on Spectroscopic Ellipsometry (ICSE). Thin Solid Films, 571, 371-376
Öppna denna publikation i ny flik eller fönster >>On the complex refractive index of polymer:fullerene photovoltaic blends
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2014 (Engelska)Ingår i: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 571, s. 371-376Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

We present a detailed investigation of the refractive index of polymer:fullerene blends for photovoltaic applications. The donor polymers poly[2,7-(9,9-dioctylfluorene)-alt-5,5-(4,7-di-2-thienyl-2,1,3-benzothiadiazole)] (APFO3), poly[2,3-bis-(3-octyloxyphenyl)quinoxaline-5,8-diyl-alt-thiophene-2,5-diyl] (TQ1), and poly[2,7-(9,9-dioctylfluorene)-alt-5,5-(5,10-di-2-thienyl-2,3,7,8-tetraphenyl-pyrazino[2,3-g] quinoxaline)] (APFO-Green9) were blended with either [6,6]-phenyl-C-61-butyric acid methyl ester (PCBM) or [6,6]-phenyl-C-71-butyric acid methyl ester (PC71BM). We measured variable angle spectroscopic ellipsometry for three systems, namely APFO3:PCBM, TQ1:PC71BM and APFO-Green9:PC71BM, as a function of composition and analyze the data employing a number of models. We found that Bruggeman effective medium approximations (EMA) are not precise for the description of the optical properties of these blends. This is due to a number of reasons. First, we find that there are energy shifts associated to changes in conjugation length that cannot be accounted for using EMA. Second, blending results in a strong reduction of anisotropy. Finally, our data suggest that there is some degree of vertical segregation between components. Therefore, our results support the idea that the optical properties of polymer:fullerene mixtures should be treated as alloys rather than non-interacting blends.

Ort, förlag, år, upplaga, sidor
Elsevier, 2014
Nyckelord
Bulk heterojunction; Organic solar cells; Effective medium approximation; Anisotropy; Vertical segregation; Ellipsometry
Nationell ämneskategori
Biologiska vetenskaper
Identifikatorer
urn:nbn:se:liu:diva-113190 (URN)10.1016/j.tsf.2014.02.096 (DOI)000346055200006 ()
Konferens
6th International Conference on Spectroscopic Ellipsometry (ICSE)
Tillgänglig från: 2015-01-13 Skapad: 2015-01-12 Senast uppdaterad: 2017-12-05
Müller, C., Andersson, M., Pena-Rodriguez, O., Garriga, M., Inganäs, O. & Campoy-Quiles, M. (2013). Determination of Thermal Transition Depth Profiles in Polymer Semiconductor Films with Ellipsometry. Macromolecules, 46(18), 7325-7331
Öppna denna publikation i ny flik eller fönster >>Determination of Thermal Transition Depth Profiles in Polymer Semiconductor Films with Ellipsometry
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2013 (Engelska)Ingår i: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 46, nr 18, s. 7325-7331Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Geometric confinement and interface effects can significantly alter the thermodynamic properties of thin polymer films. Phase transition temperatures have been shown to strongly depend on film thickness below a critical thickness threshold. It has been suggested that this behavior is due to an interface-induced continuous variation in phase transition 200 temperatures throughout the depth of the films. Here we employ variable-temperature spectroscopic ellipsometry to demonstrate the existence of these depth profiles. We examine four different polymer semiconductors that are of interest for organic light-emitting diodes, solar cells, and field-effect transistors. In contrast to insulating polymers, these light-absorbing materials provide detailed information about structural changes as a function of depth due to wavelength-dependent attenuation. This concept enables us to investigate a broad range of thermodynamic processes including the glass transition, crystallization as well as crystalline and liquid-crystalline melting. In general, for the here investigated systems, higher transition temperatures are found at the free surface. Finally, the deduced profiles are used to predict the thickness dependence of the mean phase transition temperature.

Ort, förlag, år, upplaga, sidor
American Chemical Society, 2013
Nationell ämneskategori
Teknik och teknologier
Identifikatorer
urn:nbn:se:liu:diva-104302 (URN)10.1021/ma400871u (DOI)000330145700021 ()
Tillgänglig från: 2014-02-17 Skapad: 2014-02-14 Senast uppdaterad: 2017-12-06
Müller, C., Esmaeili, M., Riekel, C., Breiby, D. W. & Inganäs, O. (2013). Micro X-ray diffraction mapping of a fluorene copolymer fibre. Polymer, 54(2), 805-811
Öppna denna publikation i ny flik eller fönster >>Micro X-ray diffraction mapping of a fluorene copolymer fibre
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2013 (Engelska)Ingår i: Polymer, ISSN 0032-3861, E-ISSN 1873-2291, Vol. 54, nr 2, s. 805-811Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Using raster-scanning wide-angle X-ray scattering, we investigate oriented fibres of the low bandgap conjugated polymer, poly[2,7-(9,9-dioctylfluorene)-alt-5,5-(4,7-di-2-thienyl-2,1,3-benzothiadiazole)] (F8TBT), that was developed in particular for polymer solar cells. For the first time, structural data are provided for F8TBT. Our results demonstrate that the nano-scale structure of this polymer is closely related to the externally observable features of the fibre, and thus emphasise the importance of having full control over the local molecular conformation. Liquid-crystalline phases are observed at elevated temperatures, and the molecular alignment in the drawn fibres yields scattering patterns that are dominated by broad peaks of equatorial diffuse scattering. The significant degree of preferred orientation facilitates the analysis, leading to estimates of (average) nearest-neighbour packing distances and coherence length of this macromolecule. In particular, we observe a pronounced broad signal assigned to packing of the conjugated backbone with an approximate spacing of 4.00-4.39 angstrom that is coherent over 5-6 polymer segments.

Ort, förlag, år, upplaga, sidor
Elsevier, 2013
Nyckelord
Conjugated polymer fibre, Synchrotron X-ray diffraction, Liquid-crystalline polymer
Nationell ämneskategori
Teknik och teknologier
Identifikatorer
urn:nbn:se:liu:diva-89747 (URN)10.1016/j.polymer.2012.10.059 (DOI)000314085000042 ()
Anmärkning

Funding Agencies|Northern European Innovative Energy Research Programme (N-INNER)||Swedish Energy Agency||Norwegian Research Council||Statoil ASA||Total EP Norge AS||Janus Holdings AS||Wenaas AS||Swix Sport AS||

Tillgänglig från: 2013-03-05 Skapad: 2013-03-05 Senast uppdaterad: 2017-12-06
Müller, C., Jansson, R., Elfwing, A., Askarieh, G., Karlsson, R., Hamedi, M., . . . Hedhammar, M. (2011). Functionalisation of recombinant spider silk with conjugated polyelectrolytes. Journal of Materials Chemistry, 21(9), 2909-2915
Öppna denna publikation i ny flik eller fönster >>Functionalisation of recombinant spider silk with conjugated polyelectrolytes
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2011 (Engelska)Ingår i: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 21, nr 9, s. 2909-2915Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Conjugated polyelectrolytes are demonstrated to permit facile staining of recombinant spider silk fibres. We find that the polyelectrolyte concentration and pH of the staining solution as well as the incubation temperature strongly influence the efficiency of this self-assembly process, which appears to be principally mediated through favourable electrostatic interactions. Thus, depending on the choice of staining conditions as well as the polyelectrolyte, electrically conductive or photoluminescent recombinant silk fibres could be produced. In addition, staining of natural Bombyx mori silk is established, which emphasises the versatility of the here advanced approach to functionalise silk-based materials.

Ort, förlag, år, upplaga, sidor
Royal Society of Chemistry, 2011
Nationell ämneskategori
Teknik och teknologier
Identifikatorer
urn:nbn:se:liu:diva-66131 (URN)10.1039/c0jm03270k (DOI)000287369300019 ()
Tillgänglig från: 2011-03-04 Skapad: 2011-03-04 Senast uppdaterad: 2017-12-11
Hou, L., Wang, E., Bergqvist, J., Andersson, V., Wang, Z., Müller, C., . . . Inganäs, O. (2011). Lateral Phase Separation Gradients in Spin-Coated Thin Films of High-Performance Polymer: Fullerene Photovoltaic Blends. Advanced Functional Materials, 21(16), 3169-3175
Öppna denna publikation i ny flik eller fönster >>Lateral Phase Separation Gradients in Spin-Coated Thin Films of High-Performance Polymer: Fullerene Photovoltaic Blends
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2011 (Engelska)Ingår i: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 21, nr 16, s. 3169-3175Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

In this study, it is demonstrated that a finer nanostructure produced under a rapid rate of solvent removal significantly improves charge separation in a high-performance polymer: fullerene bulk-heterojunction blend. During spin-coating, variations in solvent evaporation rate give rise to lateral phase separation gradients with the degree of coarseness decreasing away from the center of rotation. As a result, across spin-coated thin films the photocurrent at the first interference maximum varies as much as 25%, which is much larger than any optical effect. This is investigated by combining information on the surface morphology of the active layer imaged by atomic force microscopy, the 3D nanostructure imaged by electron tomography, film formation during the spin coating process imaged by optical interference and photocurrent generation distribution in devices imaged by a scanning light pulse technique. The observation that the nanostructure of organic photovoltaic blends can strongly vary across spin-coated thin films will aid the design of solvent mixtures suitable for high molecular-weight polymers and of coating techniques amenable to large area processing.

Ort, förlag, år, upplaga, sidor
Wiley-VCH Verlag Berlin, 2011
Nationell ämneskategori
Teknik och teknologier
Identifikatorer
urn:nbn:se:liu:diva-70526 (URN)10.1002/adfm.201100566 (DOI)000294166200019 ()
Anmärkning

Funding Agencies|Swedish Energy Agency||Spanish Ministerio de Ciencia e Innovacion||

Tillgänglig från: 2011-09-12 Skapad: 2011-09-12 Senast uppdaterad: 2017-12-08Bibliografiskt granskad
Müller, C. & Inganäs, O. (2011). Lyotropic phase behaviour of dilute, aqueous hen lysozyme amyloid fibril dispersions. JOURNAL OF MATERIALS SCIENCE, 46(11), 3687-3692
Öppna denna publikation i ny flik eller fönster >>Lyotropic phase behaviour of dilute, aqueous hen lysozyme amyloid fibril dispersions
2011 (Engelska)Ingår i: JOURNAL OF MATERIALS SCIENCE, ISSN 0022-2461, Vol. 46, nr 11, s. 3687-3692Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

We explore the lyotropic phase behaviour of dilute, aqueous amyloid fibril dispersions from hen egg white lysozyme with respect to protein and acid concentration in order to establish preparation protocols that provide homogeneous nematic phases. Such ordered dispersions are demonstrated to facilitate alignment of amyloid nanofibrils in thin solid films, which are utilised to structure conjugated (poly)electrolytes. In addition, the occurrence of ordered phases is found to be in good qualitative agreement with phase equilibria predicted for dispersions of rod-like particles.

Ort, förlag, år, upplaga, sidor
Springer Science Business Media, 2011
Nationell ämneskategori
Teknik och teknologier
Identifikatorer
urn:nbn:se:liu:diva-67305 (URN)10.1007/s10853-011-5363-5 (DOI)000288514500002 ()
Tillgänglig från: 2011-04-08 Skapad: 2011-04-08 Senast uppdaterad: 2015-05-29
Schmidt, D., Müller, C., Hofmann, T., Inganäs, O., Arwin, H., Schubert, E. & Schubert, M. (2011). Optical properties of hybrid titanium chevron sculptured thin films coated with a semiconducting polymer. THIN SOLID FILMS, 519(9), 2645-2649
Öppna denna publikation i ny flik eller fönster >>Optical properties of hybrid titanium chevron sculptured thin films coated with a semiconducting polymer
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2011 (Engelska)Ingår i: THIN SOLID FILMS, ISSN 0040-6090, Vol. 519, nr 9, s. 2645-2649Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Optical and structural properties of a hybrid metallic chevron sculptured thin film from titanium coated with the semiconducting polymer poly(3-dodecylthiophene) (P3DDT) are reported. The nanostructured thin film with two subsequent layers of oppositely slanted nanocolumns was fabricated by glancing angle deposition and coated with P3DDT by a spin-cast process. Spectroscopic generalized ellipsometry is employed to determine geometrical structure properties and the anisotropic optical constants of the coated and uncoated film in the spectral range from 400 to 1700 nm. The nanostructured thin films before and after hybridization show highly anisotropic optical properties. The complex refractive indices along major polarizability directions of the hybridized chevrons are increased in the entire investigated spectral range with respect to the as-deposited chevrons. Changes in birefringence and dichroism upon polymer infiltration are observed.

Ort, förlag, år, upplaga, sidor
ELSEVIER SCIENCE SA, PO BOX 564, 1001 LAUSANNE, SWITZERLAND, 2011
Nyckelord
Generalized ellipsometry, Hybrid materials, Glancing angle deposition, Sculptured thin films, Anisotropy
Nationell ämneskategori
Teknik och teknologier
Identifikatorer
urn:nbn:se:liu:diva-67700 (URN)10.1016/j.tsf.2010.12.111 (DOI)000289174200017 ()
Tillgänglig från: 2011-04-26 Skapad: 2011-04-26 Senast uppdaterad: 2013-10-14
Kylberg, W., Sonar, P., Heier, J., Tisserant, J.-N., Müller, C., Nueesch, F., . . . Hany, R. (2011). Synthesis, thin-film morphology, and comparative study of bulk and bilayer heterojunction organic photovoltaic devices using soluble diketopyrrolopyrrole molecules. Energy & Environmental Science, 4(9), 3617-3624
Öppna denna publikation i ny flik eller fönster >>Synthesis, thin-film morphology, and comparative study of bulk and bilayer heterojunction organic photovoltaic devices using soluble diketopyrrolopyrrole molecules
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2011 (Engelska)Ingår i: Energy & Environmental Science, ISSN 1754-5692, E-ISSN 1754-5706, Vol. 4, nr 9, s. 3617-3624Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Diketopyrrolopyrrole (DPP)-based organic semiconductors EH-DPP-TFP and EH-DPP-TFPV with branched ethyl-hexyl solubilizing alkyl chains and end capped with trifluoromethyl phenyl groups were designed and synthesized via Suzuki coupling. These compounds show intense absorptions up to 700 nm, and thin film-forming characteristics that sensitively depend on the solvent and coating conditions. Both materials have been used as electron donors in bulk heterojunction and bilayer organic photovoltaic (OPV) devices with fullerenes as acceptors and their performance has been studied in detail. The best power conversion efficiency of 3.3% under AM1.5G illumination (100 mW cm(-2)) was achieved for bilayer solar cells when EH-DPP-TFPV was used with C(60), after a thermal annealing step to induce dye aggregation and interdiffusion of C(60) with the donor material. To date, this is one of the highest efficiencies reported for simple bilayer OPV devices.

Ort, förlag, år, upplaga, sidor
Royal Society of Chemistry, 2011
Nationell ämneskategori
Teknik och teknologier
Identifikatorer
urn:nbn:se:liu:diva-71108 (URN)10.1039/c1ee01544c (DOI)000294306900059 ()
Tillgänglig från: 2011-09-30 Skapad: 2011-09-30 Senast uppdaterad: 2017-12-08
Müller, C., Hamedi, M., Karlsson, R., Jansson, R., Marcilla, R., Hedhammar, M. & Inganäs, O. (2011). Woven Electrochemical Transistors on Silk Fibers. ADVANCED MATERIALS, 23(7), 898
Öppna denna publikation i ny flik eller fönster >>Woven Electrochemical Transistors on Silk Fibers
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2011 (Engelska)Ingår i: ADVANCED MATERIALS, ISSN 0935-9648, Vol. 23, nr 7, s. 898-Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Woven electrochemical transistors on silk fibers from the silkworm Bombyx mori are demonstrated. This is achieved with carefully chosen electrolyte chemistry: electrically conducting silk fibers are produced by dyeing silk fibers with a conjugated polyelectrolyte and gating is accomplished by use of an electrolyte mixture composed of imidazolium-based ionic liquids.

Ort, förlag, år, upplaga, sidor
John Wiley and Sons, Ltd, 2011
Nationell ämneskategori
Teknik och teknologier
Identifikatorer
urn:nbn:se:liu:diva-66903 (URN)10.1002/adma.201003601 (DOI)000287668500015 ()
Tillgänglig från: 2011-03-21 Skapad: 2011-03-21 Senast uppdaterad: 2015-05-29
Müller, C., Wang, E., Andersson, M., Tvingstedt, K., Zhou, Y., Andersson, M. R. & Inganäs, O. (2010). Influence of Molecular Weight on the Performance of Organic Solar Cells Based on a Fluorene Derivative. ADVANCED FUNCTIONAL MATERIALS, 20(13), 2124-2131
Öppna denna publikation i ny flik eller fönster >>Influence of Molecular Weight on the Performance of Organic Solar Cells Based on a Fluorene Derivative
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2010 (Engelska)Ingår i: ADVANCED FUNCTIONAL MATERIALS, ISSN 1616-301X, Vol. 20, nr 13, s. 2124-2131Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

The performance of organic photovoltaic (OPV) bulk-heterojunction blends comprising a liquid-crystalline fluorene derivative and a small-molecular fullerene is found to increase asymptotically with the degree of polymerization of the former. Similar to various thermodynamic transition temperatures as well as the light absorbance of the fluorene moiety, the photocurrent extracted from OPV devices is found to strongly vary with increasing oligomer size up to a number average molecular weight, M-n approximate to 10 kg mol(-1), but is rendered less chain-length dependent for higher M-n as the fluorene derivative gradually adopts polymeric behavior.

Ort, förlag, år, upplaga, sidor
John Wiley and Sons, Ltd, 2010
Nationell ämneskategori
Teknik och teknologier
Identifikatorer
urn:nbn:se:liu:diva-58539 (URN)10.1002/adfm.201000224 (DOI)000280276900013 ()
Tillgänglig från: 2010-08-13 Skapad: 2010-08-13 Senast uppdaterad: 2015-05-29
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