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Publications (10 of 10) Show all publications
Sheng, X., Li, Y., Yang, T., Timmer, B., Willhammar, T., Cheung, O., . . . Sun, L. (2020). Hierarchical micro-reactor as electrodes for water splitting by metal rod tipped carbon nanocapsule self-assembly in carbonized wood. Applied Catalysis B: Environmental, 264, Article ID 118536.
Open this publication in new window or tab >>Hierarchical micro-reactor as electrodes for water splitting by metal rod tipped carbon nanocapsule self-assembly in carbonized wood
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2020 (English)In: Applied Catalysis B: Environmental, ISSN 0926-3373, E-ISSN 1873-3883, Vol. 264, article id 118536Article in journal (Refereed) Published
Abstract [en]

Materials design of efficient electrochemical micro-reactors is challenging, although hierarchically structured, self-standing electrodes with catalyst arrays offer promise. Herein, catalyst function in compact micro-reactor electrodes is designed by nanostructural tailoring of carbonized wood for efficient water splitting. Specifically, NiFe rod tipped, N-doped graphitic carbon nanocapsule arrays are self-assembled in hierarchical wood, and the benefit of this unique presentation and its promotive effect on accessibility of the catalyst surfaces is apparent. This report also comprises the first wood based micro-reactor electrodes for electrocatalytic water oxidation demonstrating excellent performance. The overpotential for oxygen evolution reaction was as low as 180 mV for 10 mA cm−2 current density and TOFredox was high at a level of 5.8 s−1 (at 370 mV overpotential). This hierarchical electrode can also work as bifunctional catalyst (both as anodic and as cathodic electrode) for total water splitting with a cell potential of 1.49 V for 10 mA cm−2 in alkaline solution, suggestive of their potential also in other electrochemical applications.

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Carbonized wood, Metal rod tipped carbon nanocapsules, Microfluidic electrodes, Oxygen evolution reaction
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-267782 (URN)10.1016/j.apcatb.2019.118536 (DOI)2-s2.0-85076717565 (Scopus ID)
Note

QC 20200304

Available from: 2020-03-04 Created: 2020-03-04 Last updated: 2020-03-04Bibliographically approved
Jawerth, M., Brett, C., Terrier, C., Larsson, P. T., Lawoko, M., Roth, S. V., . . . Johansson, M. (2020). Mechanical and Morphological Properties of Lignin-Based Thermosets. ACS APPLIED POLYMER MATERIALS, 2(2), 668-676
Open this publication in new window or tab >>Mechanical and Morphological Properties of Lignin-Based Thermosets
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2020 (English)In: ACS APPLIED POLYMER MATERIALS, ISSN 2637-6105, Vol. 2, no 2, p. 668-676Article in journal (Refereed) Published
Abstract [en]

The need for renewable alternatives for fossil-based aromatic material constituents is evident for a more sustainable society. Lignin is the largest source of naturally occurring aromatic compounds but has mainly been considered as waste material or energy source in the pulp and paper industry. Developments in extracting lignin from these processes provide a large source for renewable aromatic structures to be used in various applications. Producing thermosets out of lignin is a very promising route to utilize this raw material toward, for example, composite application. The buildup of the molecular network based on oligomeric lignin segments will be different from traditional thermoset analogues, where the constituents often are smaller molecules, and will have an effect on the material properties. In this work LignoBoost Kraft lignin is refined, chemically modified, and used to produce freestanding thermosets with different architectures and properties. These different thermosets are evaluated, and the possibilities to tailor the material properties through work-up and modification are demonstrated. Morphological studies on the formed thermosets using X-ray scattering show systematic differences in molecular stacking and aggregate sizes.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2020
Keywords
lignin fractions, aryl allyl ethers, thiol-ene thermoset, mechanical properties, small- and wide-angle X-ray scattering
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:kth:diva-271305 (URN)10.1021/acsapm.9b01007 (DOI)000514258700059 ()
Note

QC 20200331

Available from: 2020-03-31 Created: 2020-03-31 Last updated: 2020-03-31Bibliographically approved
Josefsson, L., Ye, X., Brett, C., Meijer, J., Olsson, C., Sjögren, A., . . . Lendel, C. (2020). Potato Protein Nanofibrils Produced from a Starch Industry Sidestream. ACS SUSTAINABLE CHEMISTRY & ENGINEERING, 8(2), 1058-1067
Open this publication in new window or tab >>Potato Protein Nanofibrils Produced from a Starch Industry Sidestream
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2020 (English)In: ACS SUSTAINABLE CHEMISTRY & ENGINEERING, ISSN 2168-0485, Vol. 8, no 2, p. 1058-1067Article in journal (Refereed) Published
Abstract [en]

Protein nanofibrils have emerged as promising building blocks in functional bio/nanomaterials as well as in food products. We here demonstrate that nanofibrils with amyloid-like properties can be produced from potato protein isolate, a major sidestream from the starch industry. Methods for solubilization of potato proteins are evaluated, and a protocol for the assembly of protein nanofibrils is presented. Characterization of the nanofibrils shows that they are rich in beta-sheet structure and display the cross-beta X-ray fiber diffraction pattern, which is a hallmark of amyloid-like fibrils. Atomic force microscopy shows that the fibrils are ca. 4-5 nm in diameter with a nanoscale morphology that displays a high degree of curvature. Using mass spectrometry we identify four peptides that constitute the core building blocks of the nanofibrils and show that they originate from two different classes of proteins. The structural characteristics of these peptides are distinct from previously studied plant protein nanofibrils and thereby reveal new knowledge about the formation of protein nanostructures from agricultural resources.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2020
Keywords
Potato protein, Nanomaterials, Biobased materials, Amyloid, Mass spectrometry
National Category
Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:kth:diva-268715 (URN)10.1021/acssuschemeng.9b05865 (DOI)000509432200036 ()
Note

QC 20200220

Available from: 2020-02-20 Created: 2020-02-20 Last updated: 2020-02-20Bibliographically approved
Gensch, M., Schwartzkopf, M., Ohm, W., Brett, C., Pandit, P., Varalil, S. K., . . . Roth, S. V. (2019). Correlating Nanostructure, Optical and Electronic Properties of Nanogranular Silver Layers during Polymer-Template-Assisted Sputter Deposition. ACS Applied Materials and Interfaces, 11(32), 29416-29426
Open this publication in new window or tab >>Correlating Nanostructure, Optical and Electronic Properties of Nanogranular Silver Layers during Polymer-Template-Assisted Sputter Deposition
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2019 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 11, no 32, p. 29416-29426Article in journal (Refereed) Published
Abstract [en]

Tailoring the optical and electronic properties of nanostructured polymer-metal composites demonstrates great potential for efficient fabrication of modern organic optical and electronic devices such as flexible sensors, transistors, diodes, or photovoltaics. Self-assembled polymer metal nanocomposites offer an excellent perspective for creating hierarchical nanostructures on macroscopic scales by simple bottom-up processes. We investigate the growth processes of nanogranular silver (Ag) layers on diblock copolymer thin film templates during sputter deposition. The Ag growth is strongly driven by self-assembly and selective wetting on the lamella structure of polystyrene-block-poly (methyl methacrylate). We correlate the emerging nanoscale morphologies with collective optical and electronic properties and quantify the difference in Ag growth on the corresponding homopolymer thin films. Thus, we are able to determine the influence of the respective polymer template and observe substrate effects on the Ag cluster percolation threshold, which affects the insulator-to-metal transition (IMT). Optical spectroscopy in the UV-vis regime reveals localized surface plasmon resonance for the metal polymer composite. Their maximum absorption is observed around the IMT due to the subsequent long-range electron conduction in percolated nanogranular Ag layers. Using X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy, we identify the oxidation of Ag at the acrylate side chains as an essential influencing factor driving the selective wetting behavior in the early growth stages. The results of polymer-templated cluster growth are corroborated by atomic force microscopy and field emission scanning electron microscopy.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2019
Keywords
polymer-metal interface, metal cluster percolation, growth kinetics, GISAXS, block copolymer
National Category
Materials Chemistry
Identifiers
urn:nbn:se:kth:diva-257808 (URN)10.1021/acsami.9b08594 (DOI)000481567100090 ()31313904 (PubMedID)2-s2.0-85071352839 (Scopus ID)
Note

QC 20190912

Available from: 2019-09-12 Created: 2019-09-12 Last updated: 2019-09-12Bibliographically approved
Glier, T. E., Akinsinde, L., Paufler, M., Otto, F., Hashemi, M., Grote, L., . . . Ruebhausen, M. (2019). Functional Printing of Conductive Silver-Nanowire Photopolymer Composites. Scientific Reports, 9, Article ID 6465.
Open this publication in new window or tab >>Functional Printing of Conductive Silver-Nanowire Photopolymer Composites
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2019 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, article id 6465Article in journal (Refereed) Published
Abstract [en]

We investigated the fabrication and functional behaviour of conductive silver-nanowire-polymer composites for prospective use in printing applications. Silver-nanowires with an aspect ratio of up to 1000 were synthesized using the polyol route and embedded in a UV-curable and printable polymer matrix. Sheet resistances in the composites down to 13 Omega/sq at an optical transmission of about 90% were accomplished. The silver-nanowire composite morphology and network structure was investigated by electron microscopy, atomic force microscopy, profilometry, ellipsometry as well as surface sensitive X-ray scattering. By implementing different printing applications, we demonstrate that our silver nanowires can be used in different polymer composites. On the one hand, we used a tough composite for a 2D-printed film as top contact on a solar cell. On the other hand, a flexible composite was applied for a 3D-printed flexible capacitor.

Place, publisher, year, edition, pages
NATURE PUBLISHING GROUP, 2019
National Category
Composite Science and Engineering
Identifiers
urn:nbn:se:kth:diva-251276 (URN)10.1038/s41598-019-42841-3 (DOI)000465218400016 ()31015552 (PubMedID)2-s2.0-85064889866 (Scopus ID)
Note

QC 20190514

Available from: 2019-05-14 Created: 2019-05-14 Last updated: 2019-05-29Bibliographically approved
Brett, C., Mittal, N., Ohm, W., Söderberg, D. & Roth, S. V. (2019). GISAS study of spray deposited metal precursor ink on a cellulose template. Paper presented at National Meeting of the American-Chemical-Society (ACS), MAR 31-APR 04, 2019, Orlando, FL. Abstracts of Papers of the American Chemical Society, 257
Open this publication in new window or tab >>GISAS study of spray deposited metal precursor ink on a cellulose template
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2019 (English)In: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 257Article in journal, Meeting abstract (Other academic) Published
Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2019
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:kth:diva-257597 (URN)000478860503076 ()
Conference
National Meeting of the American-Chemical-Society (ACS), MAR 31-APR 04, 2019, Orlando, FL
Note

QC 20190919

Available from: 2019-09-19 Created: 2019-09-19 Last updated: 2019-09-19Bibliographically approved
Ohm, W., Rothkirch, A., Pandit, P., Koerstgens, V., Mueller-Buschbaum, P., Rojas, R., . . . Roth, S. V. (2019). Morphological and crystalline properties of airbrush spray-deposited enzymatic cellulose thin films. Paper presented at National Meeting of the American-Chemical-Society (ACS), MAR 31-APR 04, 2019, Orlando, FL. Abstracts of Papers of the American Chemical Society, 257
Open this publication in new window or tab >>Morphological and crystalline properties of airbrush spray-deposited enzymatic cellulose thin films
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2019 (English)In: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 257Article in journal, Meeting abstract (Other academic) Published
Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2019
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:kth:diva-257617 (URN)000478860502739 ()
Conference
National Meeting of the American-Chemical-Society (ACS), MAR 31-APR 04, 2019, Orlando, FL
Note

QC 20190918

Available from: 2019-09-18 Created: 2019-09-18 Last updated: 2019-09-18Bibliographically approved
Li, N., Song, L., Biessmann, L., Xia, S., Ohm, W., Brett, C., . . . Mueller-Buschbaum, P. (2019). Morphology Phase Diagram of Slot-Die Printed TiO2 Films Based on Sol-Gel Synthesis. Advanced Materials Interfaces, 6(12), Article ID 1900558.
Open this publication in new window or tab >>Morphology Phase Diagram of Slot-Die Printed TiO2 Films Based on Sol-Gel Synthesis
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2019 (English)In: Advanced Materials Interfaces, ISSN 2196-7350, Vol. 6, no 12, article id 1900558Article in journal (Refereed) Published
Abstract [en]

Mesoporous titania films with tailored nanostructures are fabricated via slot-die printing, which is a simple and cost-effective thin-film deposition technique with the possibility of a large-scale manufacturing. Based on this technique, which is favorable in industry, TiO2 films possess the similar advantage with polymer semiconducting devices like ease of large-scale production. The titania morphologies, including foam-like nanostructures, nanowire aggregates, collapsed vesicles and nanogranules, are achieved via a so-called block-copolymer-assisted sol-gel synthesis. By adjusting the weight fraction of reactants, the ternary morphology phase diagram of the printed titania films is probed after template removal. The surface and inner morphology evolutions are explored with scanning electron microscopy and grazing incidence small-angle X-ray scattering, respectively. Special focus is set on foam-like titania nanostructures as they are of especial interest for, e.g., solar cell applications. At a low weight fraction of the titania precursor titanium(IV)isopropoxide (TTIP), foam-like titania films are achieved, which exhibit a high uniformity and possess large pore sizes. The anatase phase of the highly crystalline titania films is verified with X-ray diffraction and transmission electron microscopy.

Place, publisher, year, edition, pages
WILEY, 2019
Keywords
crystallinity, GISAXS, morphology phase diagram, printing, TiO2 films
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-256285 (URN)10.1002/admi.201900558 (DOI)000477979500004 ()2-s2.0-85065237302 (Scopus ID)
Note

QC 20191105

Available from: 2019-11-05 Created: 2019-11-05 Last updated: 2019-11-05Bibliographically approved
Zhang, F., Yao, Z., Guo, Y., Li, Y., Bergstrand, J., Brett, C., . . . Sun, L. (2019). Polymeric, Cost-Effective, Dopant-Free Hole Transport Materials for Efficient and Stable Perovskite Solar Cells. Journal of the American Chemical Society, 141(50), 19700-19707
Open this publication in new window or tab >>Polymeric, Cost-Effective, Dopant-Free Hole Transport Materials for Efficient and Stable Perovskite Solar Cells
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2019 (English)In: Journal of the American Chemical Society, Vol. 141, no 50, p. 19700-19707Article in journal (Refereed) Published
Abstract [en]

Perovskite solar cells (PSCs) has skyrocketed in the past decade to an unprecedented level due to their outstanding photoelectric properties and facile processability. However, the utilization of expensive hole transport materials (HTMs) and the inevitable instability instigated by the deliquescent dopants represent major concerns hindering further commercialization. Here, a series of low-cost, conjugated polymers are designed and applied as dopant-free HTMs in PSCs, featuring tuned energy levels, good temperature and humidity resistivity, and excellent photoelectric properties. Further studies highlight the critical and multifaceted roles of the polymers with respect to facilitating charge separation, passivating the surface trap sites of perovskite materials, and guaranteeing long-term stability of the devices. A stabilized power conversion efficiency (PCE) of 20.3% and remarkably enhanced device longevity are achieved using the dopant-free polymer P3 with a low concentration of 5 mg/mL, qualifying the device as one of the best PSC systems constructed on the basis of dopant-free HTMs so far. In addition, the flexible PSCs based on P3 also exhibit a PCE of 16.2%. This work demonstrates a promising route toward commercially viable, stable, and efficient PSCs.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2019
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-268287 (URN)10.1021/jacs.9b08424 (DOI)000503917800028 ()31747277 (PubMedID)2-s2.0-85076243482 (Scopus ID)
Note

QC 20200318

Available from: 2020-03-18 Created: 2020-03-18 Last updated: 2020-04-02Bibliographically approved
Brett, C., Mittal, N., Ohm, W., Söderberg, D. & Roth, S. V. (2018). In situ self-assembly study in bio-based thin films. Paper presented at 255th National Meeting and Exposition of the American-Chemical-Society (ACS) - Nexus of Food, Energy, and Water, MAR 18-22, 2018, New Orleans, LA. Abstract of Papers of the American Chemical Society, 255
Open this publication in new window or tab >>In situ self-assembly study in bio-based thin films
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2018 (English)In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 255Article in journal, Meeting abstract (Other academic) Published
Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2018
National Category
Chemical Engineering
Identifiers
urn:nbn:se:kth:diva-232279 (URN)000435539906263 ()
Conference
255th National Meeting and Exposition of the American-Chemical-Society (ACS) - Nexus of Food, Energy, and Water, MAR 18-22, 2018, New Orleans, LA
Note

QC 20180718

Available from: 2018-07-18 Created: 2018-07-18 Last updated: 2018-07-18Bibliographically approved
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Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-5789-6299

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