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BETA
Brena, Barbara
Alternative names
Publications (10 of 62) Show all publications
Balatsky, A. V., Brena, B., Herper, H. C. & Sanyal, B. (2018). Functional Dirac Materials: Status and Perspectives. Physica Status Solidi. Rapid Research Letters, 12(11), Article ID 1870334.
Open this publication in new window or tab >>Functional Dirac Materials: Status and Perspectives
2018 (English)In: Physica Status Solidi. Rapid Research Letters, ISSN 1862-6254, E-ISSN 1862-6270, Vol. 12, no 11, article id 1870334Article in journal, Editorial material (Other academic) Published
Place, publisher, year, edition, pages
Wiley-VCH Verlagsgesellschaft, 2018
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-372954 (URN)10.1002/pssr.201870334 (DOI)000450130300001 ()
Available from: 2019-01-15 Created: 2019-01-15 Last updated: 2019-01-15Bibliographically approved
Farronato, M., Lüder, J., Longo, D., Cruguel, H., Bouvet, M., Brena, B. & Witkowski, N. (2018). High Tolerance of Double-Decker Phthalocyanine toward Molecular Oxygen. The Journal of Physical Chemistry C, 122(35), 20244-20251
Open this publication in new window or tab >>High Tolerance of Double-Decker Phthalocyanine toward Molecular Oxygen
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2018 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 122, no 35, p. 20244-20251Article in journal (Refereed) Published
Abstract [en]

Because organic electronics suffer from degradation-inducing oxidation processes, oxygen-tolerant organic molecules could solve this issue and be integrated to improve the stability of devices during operation. In this work, we investigate how lutetium double-decker phthalocyanine (LuPc2) reacts toward molecular oxygen and we report microscopic details of its interaction with LuPc2 film by combining X-ray photoemission spectroscopy, near-edge X-ray absorption fine structure spectroscopy, and density functional theory. Surprisingly, LuPc2 molecules are found to weakly physisorb below 120 K and appear rather inert to molecular oxygen at more elevated temperatures. We are able to draw a microscopic picture at low temperature, in which oxygen molecules stick on top of the pyrrolic carbon of LuPc2. Our work sheds light on a class of semiconducting molecules, namely, double-decker phthalocyanines, which present a high tolerance toward molecular oxygen, opening promising perspectives for the design of stable materials to be applied in the next generation of organic-based electronic devices operating under ambient conditions.

National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-365654 (URN)10.1021/acs.jpcc.8b04084 (DOI)000444355400020 ()
Funder
Knut and Alice Wallenberg FoundationEU, FP7, Seventh Framework Programme, 607232 THINFACESwedish Research Council, 2014-3776Swedish National Infrastructure for Computing (SNIC)
Available from: 2018-11-16 Created: 2018-11-16 Last updated: 2018-11-16Bibliographically approved
Zhang, T., Brumboiu, I. E., Grazioli, C., Guarnaccio, A., Coreno, M., de Simone, M., . . . Puglia, C. (2018). Lone-Pair Delocalization Effects within Electron Donor Molecules: The Case of Triphenylamine and Its Thiophene-Analog. The Journal of Physical Chemistry C, 122(31), 17706-17717
Open this publication in new window or tab >>Lone-Pair Delocalization Effects within Electron Donor Molecules: The Case of Triphenylamine and Its Thiophene-Analog
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2018 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 122, no 31, p. 17706-17717Article in journal (Refereed) Published
Abstract [en]

Triphenylamine (TPA) and its thiophene-analog, N,N-diphenyl-2-thiophenamine (DPTA), are both well-known as electron-donating molecules implemented in optoelectronic devices such as organic solar cells and LEDs. Comprehensive valence and core level photoelectron spectroscopy, as well as near edge X-ray absorption spectroscopy (NEXAFS), measurements have been performed on gas phase TPA and DPTA. The experimental results have been compared to density functional theory calculations, providing a detailed description of the molecular electronic structure. Specifically, the C 1s photoelectron lines of both TPA and DPTA were resolved in the different C atom contributions and their binding energies explained as the result of two counter-acting effects: (1) the electronegativity of the nitrogen atom (and sulfur atom in DPTA) and (2) the the N (and S in DPTA) lone-pair electrons. In addition, the C K-edge NEXAFS spectrum of DPTA reveals that the lowest unoccupied molecular orbital (LUMO) energy position is affected differently if the core hole site is on the phenyl compared to the thiophene ring. The electron-donating properties of these two molecules are largely explained by the significant contribution of the N lone-pair electrons (p(z)) to the highest occupied molecular orbital. The contribution to the LUMO and to the empty density of states of the sulfur of the thiophene ring in DPTA explains the better performance of donor-pi-acceptor molecules containing this moiety and implemented in photoenergy conversion devices.

National Category
Physical Sciences Theoretical Chemistry Condensed Matter Physics
Research subject
Physics with spec. in Atomic, Molecular and Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-355118 (URN)10.1021/acs.jpcc.8b06475 (DOI)000441484600014 ()
Funder
Swedish Research Council, VR 2014-3776Carl Tryggers foundation
Note

Title in thesis list of papers: Lone Pair Delocalization Effect within Electron Donor Molecules:The Case of Triphenylamine (TPA) and Its Thiophene-Analog(DPTA)

Available from: 2018-06-29 Created: 2018-06-29 Last updated: 2018-10-15Bibliographically approved
Farronato, M., Bidermane, I., Lüder, J., Bouvet, M., Vlad, A., Jones, A., . . . Witkowski, N. (2018). New Quadratic Self-Assembly of Double-Decker Phthalocyanine on Gold(111) Surface: From Macroscopic to Microscopic Scale. The Journal of Physical Chemistry C, 122(46), 26480-26488
Open this publication in new window or tab >>New Quadratic Self-Assembly of Double-Decker Phthalocyanine on Gold(111) Surface: From Macroscopic to Microscopic Scale
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2018 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 122, no 46, p. 26480-26488Article in journal (Refereed) Published
Abstract [en]

Unveiling the self-organization mechanism of semiconducting organic molecules onto metallic surfaces is the first step to design hybrid devices in which the self-assembling is exploited to tailor magnetic properties. In this study, double-decker rare-earth phthalocyanines, namely, lutetium phthalocyanine (LuPc2), are deposited on Au(111) gold surface forming large-scale self-assemblies. Global and local experimental techniques, namely, grazing incidence X-ray diffraction and scanning tunneling microscopy, supplemented by density functional theory calculations with van der Waals corrections, give insight into the molecular structural arrangement of the thin film and the self organization at the surface. Our results show unambiguously that the two plateaus of the double-decker phthalocyanine present a different rotation than the isolated molecule. This is evidenced by density functional theory simulations of optimized LuPc2 monolayer showing a perfect agreement with experimental findings. Moreover, the stabilized structure of double layers reveals an eclipsed configuration of the molecules in the stacking, having the ligand plateaus parallel to the gold surface. The high crystallinity of the molecular assembly and its weak electronic coupling with the metallic substrate is expected to open new perspective in magnetic devices.

National Category
Condensed Matter Physics Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-372453 (URN)10.1021/acs.jpcc.8b08462 (DOI)000451495600021 ()
Funder
Swedish Research Council, 2014-3776EU, FP7, Seventh Framework Programme, 607232 THINFACE
Available from: 2019-01-07 Created: 2019-01-07 Last updated: 2019-01-07Bibliographically approved
Zhou, Y., Silva, J. L., Woods, J. M., Pondick, J. V., Feng, Q., Liang, Z., . . . Cha, J. J. (2018). Revealing the Contribution of Individual Factors to Hydrogen Evolution Reaction Catalytic Activity. Advanced Materials, 30(18), Article ID 1706076.
Open this publication in new window or tab >>Revealing the Contribution of Individual Factors to Hydrogen Evolution Reaction Catalytic Activity
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2018 (English)In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 30, no 18, article id 1706076Article in journal (Refereed) Published
Abstract [en]

For the electrochemical hydrogen evolution reaction (HER), the electrical properties of catalysts can play an important role in influencing the overall catalytic activity. This is particularly important for semiconducting HER catalysts such as MoS2, which has been extensively studied over the last decade. Herein, on-chip microreactors on two model catalysts, semiconducting MoS2 and semimetallic WTe2, are employed to extract the effects of individual factors and study their relations with the HER catalytic activity. It is shown that electron injection at the catalyst/current collector interface and intralayer and interlayer charge transport within the catalyst can be more important than thermodynamic energy considerations. For WTe2, the site-dependent activities and the relations of the pure thermodynamics to the overall activity are measured and established, as the microreactors allow precise measurements of the type and area of the catalytic sites. The approach presents opportunities to study electrochemical reactions systematically to help establish rational design principles for future electrocatalysts.

Place, publisher, year, edition, pages
WILEY-V C H VERLAG GMBH, 2018
Keywords
2D TMD materials, electrochemical microreactors, hydrogen evolution reaction, individual factors, overall performance
National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-356393 (URN)10.1002/adma.201706076 (DOI)000431615100009 ()29573299 (PubMedID)
Funder
Swedish Research CouncilStandUp
Available from: 2018-07-25 Created: 2018-07-25 Last updated: 2018-07-25Bibliographically approved
Lanzilotto, V., Silva, J. L., Zhang, T., Stredansky, M., Grazioli, C., Simonov, K., . . . Puglia, C. (2018). Spectroscopic Fingerprints of Intermolecular H-Bonding Interactions in Carbon Nitride Model Compounds. Chemistry - A European Journal, 24(53), 14198-14206
Open this publication in new window or tab >>Spectroscopic Fingerprints of Intermolecular H-Bonding Interactions in Carbon Nitride Model Compounds
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2018 (English)In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 24, no 53, p. 14198-14206Article in journal (Refereed) Published
Abstract [en]

The effect of intermolecular H-bonding interactions on the local electronic structure of N-containing functional groups (amino group and pyridine-like N) that are characteristic of polymeric carbon nitride materials p-CN(H), a new class of metal-free organophotocatalysts, was investigated. Specifically, the melamine molecule, a building block of p-CN(H), was characterized by X-ray photoelectron (XPS) and near edge X-ray absorption fine structure (NEXAFS) spectroscopy. The molecule was studied as a noninteracting system in the gas phase and in the solid state within a H-bonded network. With the support of DFT simulations of the spectra, it was found that the H-bonds mainly affect the N1s level of the amino group, leaving the N1s level of the pyridine-like N mostly unperturbed. This is responsible for a reduction of the chemical shift between the two XPS N1s levels relative to free melamine. Consequently, N K-edge NEXAFS resonances involving the amino N1s level also shift to lower photon energies. Moreover, the solid-state absorption spectra showed significant modification/quenching of resonances related to transitions from the amino N1s level to sigma* orbitals involving the NH2 termini.

Place, publisher, year, edition, pages
WILEY-V C H VERLAG GMBH, 2018
Keywords
density functional calculations, hydrogen bonds, carbon nitrides, photoelectron spectroscopy, X-ray absorption spectroscopy
National Category
Theoretical Chemistry
Identifiers
urn:nbn:se:uu:diva-366732 (URN)10.1002/chem.201802435 (DOI)000445177600028 ()30009392 (PubMedID)
Funder
Carl Tryggers foundation
Available from: 2018-12-11 Created: 2018-12-11 Last updated: 2018-12-11Bibliographically approved
Zhang, T., Brumboiu, I. E., Lanzilotto, V., Luder, J., Grazioli, C., Giangrisostomi, E., . . . Puglia, C. (2017). Conclusively Addressing the CoPc Electronic Structure: A Joint Gas-Phase and Solid-State Photoemission and Absorption Spectroscopy Study. The Journal of Physical Chemistry C, 121(47), 26372-26378
Open this publication in new window or tab >>Conclusively Addressing the CoPc Electronic Structure: A Joint Gas-Phase and Solid-State Photoemission and Absorption Spectroscopy Study
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2017 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 121, no 47, p. 26372-26378Article in journal (Refereed) Published
Abstract [en]

The occupied and empty densities of states of cobalt phthalocyanine (CoPc) were investigated by photoelectron and X-ray absorption spectroscopies in the gas phase and in thin films deposited on a Au(111) surface. The comparison between the gas-phase results and density functional theory single-molecule simulations confirmed that the CoPc ground state is correctly described by the (2)A(1g) electronic configuration. Moreover, photon-energy-dependent valence photoemission spectra of both the gas phase and thin film confirmed the atomic character of the highest occupied molecular orbital as being derived from the organic ligand, with dominant contributions from the carbon atoms. Multiplet ligand-field theory was employed to simulate the Co L-edge X-ray absorption spectroscopy results.

National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-345249 (URN)10.1021/acs.jpcc.7b08524 (DOI)000417228500026 ()
Funder
Swedish Research CouncilCarl Tryggers foundation
Available from: 2018-03-09 Created: 2018-03-09 Last updated: 2018-03-09Bibliographically approved
Zhang, T., Brumboiu, I. E., Lanzilotto, V., Luder, J., Grazioli, C., Giangrisostomi, E., . . . Puglia, C. (2017). Conclusively Addressing the CoPc Electronic Structure: A Joint Gas-Phase and Solid-State Photoemission and Absorption Spectroscopy Study. The Journal of Physical Chemistry C, 121(47), 26372-26378
Open this publication in new window or tab >>Conclusively Addressing the CoPc Electronic Structure: A Joint Gas-Phase and Solid-State Photoemission and Absorption Spectroscopy Study
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2017 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 121, no 47, p. 26372-26378Article in journal (Refereed) Published
Abstract [en]

The occupied and empty densities of states of cobalt phthalocyanine (CoPc) were investigated by photoelectron and X-ray absorption spectroscopies in the gas phase and in thin films deposited on a Au(111) surface. The comparison between the gas-phase results and density functional theory single-molecule simulations confirmed that the CoPc ground state is correctly described by the (2)A(1g) electronic configuration. Moreover, photon-energy-dependent valence photoemission spectra of both the gas phase and thin film confirmed the atomic character of the highest occupied molecular orbital as being derived from the organic ligand, with dominant contributions from the carbon atoms. Multiplet ligand-field theory was employed to simulate the Co L-edge X-ray absorption spectroscopy results.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2017
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-344315 (URN)10.1021/acs.jpcc.7b08524 (DOI)000417228500026 ()
Funder
Swedish Research CouncilCarl Tryggers foundation
Available from: 2018-03-08 Created: 2018-03-08 Last updated: 2018-06-29Bibliographically approved
Totani, R., Grazioli, C., Zhang, T., Bidermane, I., Lüder, J., de Simone, M., . . . Puglia, C. (2017). Electronic structure investigation of biphenylene films. Journal of Chemical Physics, 146(5), Article ID 054705.
Open this publication in new window or tab >>Electronic structure investigation of biphenylene films
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2017 (English)In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 146, no 5, article id 054705Article in journal (Refereed) Published
Abstract [en]

Photoelectron Spectroscopy (PS) and Near-Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy have been used to investigate the occupied and empty density of states of biphenylene films of different thicknesses, deposited onto a Cu(111) crystal. The obtained results have been compared to previous gas phase spectra and single molecule Density Functional Theory (DFT) calculations to get insights into the possible modification of the molecular electronic structure in the film induced by the adsorption on a surface. Furthermore, NEXAFS measurements allowed characterizing the variation of the molecular arrangement with the film thickness and helped to clarify the substrate-molecule interaction. Published by AIP Publishing.

Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2017
National Category
Chemical Sciences Physical Sciences
Identifiers
urn:nbn:se:uu:diva-320469 (URN)10.1063/1.4975104 (DOI)000394576600053 ()28178795 (PubMedID)
Available from: 2017-04-26 Created: 2017-04-26 Last updated: 2017-04-26Bibliographically approved
Lüder, J., Schött, J., Brena, B., Haverkort, M. W., Thunström, P., Eriksson, O., . . . Kvashnin, Y. (2017). Theory of L-edge spectroscopy of strongly correlated systems. Physical Review B, 96(24), Article ID 245131.
Open this publication in new window or tab >>Theory of L-edge spectroscopy of strongly correlated systems
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2017 (English)In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 96, no 24, article id 245131Article in journal (Refereed) Published
Abstract [en]

X-ray absorption spectroscopy measured at the L edge of transition metals (TMs) is a powerful element-selective tool providing direct information about the correlation effects in the 3d states. The theoretical modeling of the 2p→3d excitation processes remains to be challenging for contemporary ab initio electronic structure techniques, due to strong core-hole and multiplet effects influencing the spectra. In this work, we present a realization of the method combining the density-functional theory with multiplet ligand field theory, proposed in Haverkort et al. [Phys. Rev. B 85, 165113 (2012)]. In this approach, a single-impurity Anderson model (SIAM) is constructed, with almost all parameters obtained from first principles, and then solved to obtain the spectra. In our implementation, we adopt the language of the dynamical mean-field theory and utilize the local density of states and the hybridization function, projected onto TM 3d states, in order to construct the SIAM. The developed computational scheme is applied to calculate the L-edge spectra for several TM monoxides. A very good agreement between the theory and experiment is found for all studied systems. The effect of core-hole relaxation, hybridization discretization, possible extensions of the method as well as its limitations are discussed.

National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-339767 (URN)10.1103/PhysRevB.96.245131 (DOI)000418573600012 ()
Funder
Knut and Alice Wallenberg Foundation, 2013.0020; 2012.0031Carl Tryggers foundation
Available from: 2018-02-02 Created: 2018-02-02 Last updated: 2018-10-10Bibliographically approved
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