umu.sePublications
Change search
Link to record
Permanent link

Direct link
BETA
Boulanger, Nicolas
Publications (10 of 21) Show all publications
Sandström, R., Annamalai, A., Boulanger, N., Ekspong, J., Talyzin, A., Mühlbacher, I. & Wågberg, T. (2019). Evaluation of Fluorine and Sulfonic Acid Co-functionalized Graphene Oxide Membranes in Hydrogen Proton Exchange Membrane Fuel Cell Conditions. Sustainable Energy & Fuels, 3(7), 1790-1798
Open this publication in new window or tab >>Evaluation of Fluorine and Sulfonic Acid Co-functionalized Graphene Oxide Membranes in Hydrogen Proton Exchange Membrane Fuel Cell Conditions
Show others...
2019 (English)In: Sustainable Energy & Fuels, ISSN 2398-4902, Vol. 3, no 7, p. 1790-1798Article in journal (Refereed) Published
Abstract [en]

The use of graphene oxide (GO) based membranes consisting of self-assembled flakes with a lamellar structure represents an intriguing strategy to spatially separate reactants while facilitating proton transport in proton exchange membranes (PEM). Here we chemically modify GO to evaluate the role of fluorine and sulfonic acid groups on the performance of H2/O2 based PEM fuel cells. Mild fluorination is achieved by the presence of hydrogen fluoride during oxidation and subsequent sulfonation resulted in fluorine and SO3- co-functionalized GO. Membrane electrode assembly performance in low temperature and moderate humidity conditions suggested that both functional groups contribute to reduced H2 crossover compared to appropriate reference membranes. Moreover, fluorine groups promoted an enhanced hydrolytic stability while contributing to prevent structural degradation after constant potential experiments whereas sulfonic acid demonstrated a stabilizing effect by preserving proton conductivity.

Place, publisher, year, edition, pages
Royal Society of Medicine Press, 2019
Keywords
Proton exchange membrane, Fuel Cell, Graphene oxide, Hydrogen, Fluorine, Sulfonic acid
National Category
Nano Technology Other Chemical Engineering Other Materials Engineering Energy Systems
Research subject
nanomaterials
Identifiers
urn:nbn:se:umu:diva-158496 (URN)10.1039/C9SE00126C (DOI)000472980200014 ()
Funder
Swedish Research Council, 2017-04862Swedish Energy Agency, 45419-1ÅForsk (Ångpanneföreningen's Foundation for Research and Development), 15-483Interreg Nord
Note

Originally included in thesis in manuscript form

Available from: 2019-04-29 Created: 2019-04-29 Last updated: 2019-08-05Bibliographically approved
Iakunkov, A., Sun, J., Rebrikova, A., Korobov, M., Klechikov, A., Vorobiev, A., . . . Talyzin, A. V. (2019). Swelling of graphene oxide membranes in alcohols: effects of molecule size and air ageing.. Journal of Materials Chemistry A, 7, 11331-11337
Open this publication in new window or tab >>Swelling of graphene oxide membranes in alcohols: effects of molecule size and air ageing.
Show others...
2019 (English)In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 7, p. 11331-11337Article in journal (Refereed) Published
Abstract [en]

Swelling of Hummers graphene oxide (HGO) membranes in a set of progressively longer liquid alcohols (methanol to 1-nonanol) was studied using synchrotron radiation XRD after air ageing over prolonged periods of time. Both precursor graphite oxides and freshly prepared HGO membranes were found to swell in the whole set of nine liquid alcohols with an increase of interlayer spacing from ∼7 Å (solvent free) up to ∼26 Å (in 1-nonanol). A pronounced effect of ageing on swelling in alcohols was found for HGO membranes stored in air. The HGO membranes aged for 0.5–1.5 years show progressively slower swelling kinetics, a non-monotonic decrease of saturated swelling in some alcohols and complete disappearance of swelling for alcohol molecules larger than hexanol. Moreover, the HGO membranes stored under ambient conditions for 5 years showed a nearly complete absence of swelling in all alcohols but preserved swelling in water. In contrast, precursor graphite oxide powder showed unmodified swelling in alcohols even after 4 years of ageing. Since the swelling defines the size of permeation channels, the ageing effect is one of the important parameters which could explain the strong variation in reported filtration/separation properties of GO membranes. The time and conditions of air storage require standardization for better reproducibility of results related to performance of GO membranes in various applications. The ageing of GO membranes can be considered not only as a hindrance/degradation for certain applications, but also as a method to tune the swelling properties of HGO membranes for better selectivity in sorption of solvents and for achieving better selective permeability.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2019
National Category
Materials Chemistry
Research subject
Physics
Identifiers
urn:nbn:se:umu:diva-160413 (URN)10.1039/C9TA01902B (DOI)000472225200050 ()
Funder
EU, Horizon 2020, 785219The Kempe Foundations
Available from: 2019-06-18 Created: 2019-06-18 Last updated: 2019-07-18Bibliographically approved
Annamalai, A., Sandström, R., Gracia-Espino, E., Boulanger, N., Boily, J.-F., Muehlbacher, I. & Wågberg, T. (2018). Double donor Sb5+doped hematite (Fe3+) photoanodes for surface-enhanced PEC water splitting. Paper presented at 256th National Meeting and Exposition of the American-Chemical-Society (ACS) - Nanoscience, Nanotechnology and Beyond, AUG 19-23, 2018, Boston, MA. Abstract of Papers of the American Chemical Society, 256
Open this publication in new window or tab >>Double donor Sb5+doped hematite (Fe3+) photoanodes for surface-enhanced PEC water splitting
Show others...
2018 (English)In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 256Article in journal, Meeting abstract (Other academic) Published
Place, publisher, year, edition, pages
American Chemical Society (ACS), 2018
National Category
Physical Chemistry
Identifiers
urn:nbn:se:umu:diva-153144 (URN)000447600002312 ()
Conference
256th National Meeting and Exposition of the American-Chemical-Society (ACS) - Nanoscience, Nanotechnology and Beyond, AUG 19-23, 2018, Boston, MA
Available from: 2018-11-07 Created: 2018-11-07 Last updated: 2018-11-07Bibliographically approved
Boulanger, N., Yu, V., Hilke, M., Toney, M. F. & Barbero, D. R. (2018). Graphene induced electrical percolation enables more efficient charge transport at a hybrid organic semiconductor/graphene interface. Physical Chemistry, Chemical Physics - PCCP, 20(6), 4422-4428
Open this publication in new window or tab >>Graphene induced electrical percolation enables more efficient charge transport at a hybrid organic semiconductor/graphene interface
Show others...
2018 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 20, no 6, p. 4422-4428Article in journal (Refereed) Published
Abstract [en]

Self-assembly of semiconducting polymer chains during crystallization from a liquid or melt dictates to a large degree the electronic properties of the resulting solid film. However, it is still unclear how charge transport pathways are created during crystallization. Here, we performed complementary in situ electrical measurements and synchrotron grazing incidence X-ray diffraction (GIXD), during slow cooling from the melt of highly regio-regular poly(3-hexylthiophene) (P3HT) films deposited on both graphene and on silicon. Two different charge transport mechanisms were identified, and were correlated to the difference in crystallites' orientations and overall amount of crystallites in the films on each surface as molecular self-assembly proceeded. On silicon, a weak charge transport was enabled as soon as the first edge-on lamellae formed, and further increased with the higher amount of crystallites (predominantly edge-on and randomly oriented lamellae) during cooling. On graphene however, the current remained low until a minimum amount of crystallites was reached, at which point interconnection of conducting units (face-on, randomly oriented lamellae and tie-chains) formed percolated conducting pathways across the film. This lead to a sudden rapid increase in current by approximate to 10 fold, and strongly enhanced charge transport, despite a much lower amount of crystallites than on silicon.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2018
National Category
Materials Chemistry Condensed Matter Physics
Identifiers
urn:nbn:se:umu:diva-145135 (URN)10.1039/c7cp07871d (DOI)000424357100060 ()29372204 (PubMedID)
Available from: 2018-03-05 Created: 2018-03-05 Last updated: 2018-06-09Bibliographically approved
Annamalai, A., Sandström, R., Gracia-Espino, E., Boulanger, N., Boily, J.-F., Mühlbacher, I., . . . Wågberg, T. (2018). Influence of Sb5+ as a Double Donor on Hematite (Fe3+) Photoanodes for Surface-Enhanced Photoelectrochemical Water Oxidation. ACS Applied Materials and Interfaces, 10(19), 16467-16473
Open this publication in new window or tab >>Influence of Sb5+ as a Double Donor on Hematite (Fe3+) Photoanodes for Surface-Enhanced Photoelectrochemical Water Oxidation
Show others...
2018 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, no 19, p. 16467-16473Article in journal (Refereed) Published
Abstract [en]

To exploit the full potential of hematite (α-Fe2O3) as an efficient photoanode for water oxidation, the redox processes occurring at the Fe2O3/electrolyte interface need to be studied in greater detail. Ex situ doping is an excellent technique to introduce dopants onto the photoanode surface and to modify the photoanode/electrolyte interface. In this context, we selected antimony (Sb5+) as the ex situ dopant because it is an effective electron donor and reduces recombination effects and concurrently utilize the possibility to tuning the surface charge and wettability. In the presence of Sb5+ states in Sb-doped Fe2O3 photoanodes, as confirmed by X-ray photoelectron spectroscopy, we observed a 10-fold increase in carrier concentration (1.1 × 1020 vs 1.3 × 1019 cm–3) and decreased photoanode/electrolyte charge transfer resistance (∼990 vs ∼3700 Ω). Furthermore, a broad range of surface characterization techniques such as Fourier-transform infrared spectroscopy, ζ-potential, and contact angle measurements reveal that changes in the surface hydroxyl groups following the ex situ doping also have an effect on the water splitting capability. Theoretical calculations suggest that Sb5+ can activate multiple Fe3+ ions simultaneously, in addition to increasing the surface charge and enhancing the electron/hole transport properties. To a greater extent, the Sb5+- surface-doped determines the interfacial properties of electrochemical charge transfer, leading to an efficient water oxidation mechanism.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2018
Keywords
hematite, ex situ doping, Fe2O3-Sb, water splitting, Sb5+, Fe3+, surface charge, double donors
National Category
Materials Chemistry
Identifiers
urn:nbn:se:umu:diva-148990 (URN)10.1021/acsami.8b02147 (DOI)000432753800027 ()29663796 (PubMedID)2-s2.0-85046257587 (Scopus ID)
Funder
Swedish Research Council, 2017-04862Carl Tryggers foundation , CTS-16-161Swedish Energy Agency, 45419-1
Available from: 2018-06-14 Created: 2018-06-14 Last updated: 2018-06-19Bibliographically approved
Barzegar, H. R., Larsen, C., Boulanger, N., Zettl, A., Edman, L. & Wågberg, T. (2018). Self-assembled PCBM nanosheets: a facile route to electronic layer-on-Layer heterostructures. Nano letters (Print), 18(2), 1442-1447
Open this publication in new window or tab >>Self-assembled PCBM nanosheets: a facile route to electronic layer-on-Layer heterostructures
Show others...
2018 (English)In: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 18, no 2, p. 1442-1447Article in journal, Editorial material (Refereed) Published
Abstract [en]

We report on the self-assembly of semicrystalline [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) nanosheets at the interface between a hydrophobic solvent and water, and utilize this opportunity for the realization of electronically active organic/organic molecular heterostructures. The self-assembled PCBM nanosheets can feature a lateral size of >1 cm2 and be transferred from the water surface to both hydrophobic and hydrophilic surfaces using facile transfer techniques. We employ a transferred single PCBM nanosheet as the active material in a field-effect transistor (FET) and verify semiconductor function by a measured electron mobility of 1.2 × 10–2 cm2 V–1 s–1 and an on–off ratio of ∼1 × 104. We further fabricate a planar organic/organic heterostructure with the p-type organic semiconductor poly(3-hexylthiophene-2,5-diyl) as the bottom layer and the n-type PCBM nanosheet as the top layer and demonstrate ambipolar FET operation with an electron mobility of 8.7 × 10–4 cm2 V–1 s–1 and a hole mobility of 3.1 × 10–4 cm2V–1 s–1.

Keywords
Organic electronic; organic heterostructures; PCBM nanosheets; self-assembly
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:umu:diva-144566 (URN)10.1021/acs.nanolett.7b05205 (DOI)000425559700114 ()29364679 (PubMedID)
Available from: 2018-02-06 Created: 2018-02-06 Last updated: 2018-06-13Bibliographically approved
Ekspong, J., Boulanger, N. & Gracia-Espino, E. (2018). Surface activation of graphene nanoribbons for oxygen reduction reaction by nitrogen doping and defect engineering: An ab initio study. Carbon, 137, 349-357
Open this publication in new window or tab >>Surface activation of graphene nanoribbons for oxygen reduction reaction by nitrogen doping and defect engineering: An ab initio study
2018 (English)In: Carbon, ISSN 0008-6223, E-ISSN 1873-3891, Vol. 137, p. 349-357Article in journal (Refereed) Published
Abstract [en]

Introducing heteroatoms and creating structural defects on graphene is a common and rather successful strategy to transform its inert basal plane into an efficient metal-free electrocatalyst for oxygen reduction reaction (ORR). However, the intricate atomic configuration of defective graphenes difficult their optimization as ORR electrocatalysts, where not only a large density of active sites is desirable, but also excellent electrical conductivity is required. Therefore, we used density functional theory to investigate the current-voltage characteristics and the catalytic active sites towards ORR of nitrogen-doped and defective graphene by using 8 zig-zag graphene nanoribbons as model systems. Detailed ORR catalytic activity maps are created for ten different systems showing the distribution of catalytic hot spots generated by each defect. Subsequently, the use of both current-voltage characteristics and catalytic activity maps allow to exclude inefficient systems that exhibit either low electrical conductivity or have adsorption energies far from optimal. Our study highlights the importance of considering not only the interaction energy of reaction intermediates to design electrocatalysts, but also the electrical conductivity of such configurations. We believe that this work is important for future experimental studies by providing insights on the use of graphene as a catalyst towards the ORR reaction. 

Place, publisher, year, edition, pages
PERGAMON-ELSEVIER SCIENCE LTD, 2018
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:umu:diva-151037 (URN)10.1016/j.carbon.2018.05.050 (DOI)000440661700035 ()2-s2.0-85047971117 (Scopus ID)
Available from: 2018-09-05 Created: 2018-09-05 Last updated: 2018-09-05Bibliographically approved
Boulanger, N., Yu, V., Hilke, M., Toney, M. F. & Barbero, D. R. (2017). In situ probing of the crystallization kinetics of rr-P3HT on single layer graphene as a function of temperature. Physical Chemistry, Chemical Physics - PCCP, 19(12), 8496-8503
Open this publication in new window or tab >>In situ probing of the crystallization kinetics of rr-P3HT on single layer graphene as a function of temperature
Show others...
2017 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 19, no 12, p. 8496-8503Article in journal (Refereed) Published
Abstract [en]

We studied the molecular packing and crystallization of a highly regio-regular semiconducting polymer poly(3-hexylthiophene) (P3HT) on both single layer graphene and silicon as a function of temperature, during cooling from the melt. The onset of crystallization, crystallites' size, orientation, and kinetics of formation were measured in situ by synchrotron grazing incidence X-ray diffraction (GIXD) during cooling and revealed a very different crystallization process on each surface. A favored crystalline orientation with out of plane pi-pi stacking formed at a temperature of 200 degrees C on graphene, whereas the first crystallites formed with an edge-on orientation at 185 degrees C on silicon. The crystallization of face-on lamellae revealed two surprising effects during cooling: (a) a constant low value of the pi-pi spacing below 60 degrees C; and (b) a reduction by half in the coherence length of face-on lamellae from 100 to 30 degrees C, which corresponded with the weakening of the 2nd or 3rd order of the in-plane (k00) diffraction peak. The final ratio of face-on to edge-on orientations was 40% on graphene, and 2% on silicon, revealing the very different crystallization mechanisms. These results provide a better understanding of how surfaces with different chemistries and intermolecular interactions with the polythiophene polymer chains lead to different crystallization processes and crystallites orientations for specific electronic applications.

National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:umu:diva-133743 (URN)10.1039/c6cp08589j (DOI)000397860900042 ()28287217 (PubMedID)
Available from: 2017-05-09 Created: 2017-05-09 Last updated: 2018-06-09Bibliographically approved
Barbero, D. R. & Boulanger, N. (2017). Ultralow Percolation Threshold in Nanoconfined Domains. ACS Nano, 11(10), 9906-9913
Open this publication in new window or tab >>Ultralow Percolation Threshold in Nanoconfined Domains
2017 (English)In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 11, no 10, p. 9906-9913Article in journal (Refereed) Published
Abstract [en]

Self-assembled percolated networks play an important role in many advanced electronic materials and devices. In nanocarbon composites, decreasing the percolation threshold phi(c) is of paramount importance to reduce nanotube bundling, minimize material resources and costs, and enhance charge transport. Here we demonstrate that three-dimensional nanoconfinement in single-wall carbon nanotube/polymer nanocomposites produces a strong reduction in phi(c) reaching the lowest value ever reported in this system of phi(c) approximate to 1.8 X 10(-5) wt % and 4-5 orders of magnitude lower than the theoretical statistical percolation threshold oh phi(stat) Moreover, a change in network resistivity and electrical conduction was observed with increased confinement, and a simple resistive model is used to accurately estimate the difference in is in the confined networks. These results are explained in terms of networks' size, confinement, and tube orientation as determined by atomic force microscopy, electrical conductivity measurements, and polarized Raman spectroscopy. Our findings provide important insight into nanoscale percolated networks and should find application in electronic nanocomposites and devices.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2017
Keywords
carbon nanotubes, percolation, nanoconfinement, organic electronics, charge transport
National Category
Nano Technology
Identifiers
urn:nbn:se:umu:diva-141995 (URN)10.1021/acsnano.7b03851 (DOI)000413992800032 ()28949506 (PubMedID)
Available from: 2017-11-22 Created: 2017-11-22 Last updated: 2018-06-09Bibliographically approved
Boulanger, N. (2016). Carbon nanotubes and graphene polymer composites for opto-electronic applications. (Doctoral dissertation). Umeå: Umeå universitet
Open this publication in new window or tab >>Carbon nanotubes and graphene polymer composites for opto-electronic applications
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Carbon nanotubes are carbon based structures with outstanding electronical and mechanical properties. They are used in a wide range of applications, usually embedded in polymer in the form of composites, in order to affect the electronic behavior of the matrix material. However, as the nanotubes properties are directly dependent on their intrinsic structure, it is necessary to select specific nanotubes depending on the application, which can be a complicated and inefficient process. This makes it attractive to be able to reduce the amount of material used in the composites.

In this thesis, focus is placed on the electrical properties of the composites. A simple patterning method is presented which allows the use of extremely low amounts of nanotubes in order to increase the electrical conductivity of diverse polymers such as polystyrene (PS) or poly(3-hexylthiophene) (P3HT). This method is called nanoimprint lithography and uses a flexible mold in order to pattern composite films, leading to the creation of conducting nanotube networks, resulting in vertically conducting samples (from the bottom of the film to the top of the imprinted patterns).

In parallel, X-ray diffraction measurements have been conducted on thin P3HT polymer films. These were prepared on either silicon substrate or on graphene, and the influence of the processing conditions as well as of the substrate on the crystallinity of the polymer have been investigated. The knowledge of the crystalline structure of P3HT is of great importance as it influences its electronic properties. Establishing a link between the processing conditions and the resulting crystallinity is therefore vital in order to be able to make opto-electronic devices such as transistor or photovoltaic cells.

Place, publisher, year, edition, pages
Umeå: Umeå universitet, 2016. p. 57
Keywords
carbon nanotubes, polythiophene, electrical conductivity, crystallography, graphene, nanoimprint lithography, synchrotron diffraction
National Category
Nano Technology
Research subject
Physics
Identifiers
urn:nbn:se:umu:diva-119779 (URN)978-91-7601-478-3 (ISBN)
Public defence
2016-06-01, KB3B1, KBC, Umeå, 10:00 (English)
Opponent
Supervisors
Available from: 2016-05-11 Created: 2016-04-27 Last updated: 2018-06-07Bibliographically approved
Organisations

Search in DiVA

Show all publications