Article
Materials Science, Multidisciplinary
Hassen Dakhlaoui, Shaffa Almansour, Walid Belhadj, Bryan M. Wong
Summary: This study investigates the electronic transmission and conductance of Dirac electrons in an armchair graphene nanoribbon under an external voltage using the transfer matrix method. The research shows that the transmission coefficients can be modulated by varying the order of the mode, the number of carbon atoms, and the barrier velocities, and the nanoribbon appears to be fully transparent when the barrier and Fermi velocities are equal. Numerical results demonstrate that the electronic conductance is sensitive to the applied external voltage and number of carbon atoms, suggesting potential for tailoring the electronic properties of graphene-based devices.
RESULTS IN PHYSICS
(2021)
Article
Physics, Multidisciplinary
Sofia Sanz, Nick Papior, Geza Giedke, Daniel Sanchez-Portal, Mads Brandbyge, Thomas Frederiksen
Summary: This study investigated structures composed of narrow zigzag graphene nanoribbons (GNRs) and found that the beam-splitting effect can survive under Coulomb repulsion and a spin-dependent scattering potential can emerge. The researchers also discovered that this is a general feature with edge-polarized nanoribbons, and near-perfect polarization can be achieved by joining several junctions in series.
PHYSICAL REVIEW LETTERS
(2022)
Article
Materials Science, Multidisciplinary
Van Minh Nguyen, C. S. Chu
Summary: Studied the suppression of spin relaxation rate caused by magnetic impurities in armchair graphene nanoribbons (AGNR). Found that the spin relaxation rate is significantly suppressed when the Fermi energy approaches a subband band edge. This suppression originates from the quasi-one-dimensional density of states and is manifested through the singular features in the same-site Green's function in AGNR.
Article
Chemistry, Physical
Oliver Braun, Jan Overbeck, Maria El Abbassi, Silvan Kaser, Roman Furrer, Antonis Olziersky, Alexander Flasby, Gabriela Borin Barin, Qiang Sun, Rimah Darawish, Klaus Muellen, Pascal Ruffieux, Roman Fasel, Ivan Shorubalko, Mickael L. Perrin, Michel Calame
Summary: This study reports a method for integrating atomically precise graphene nanoribbons in a field-effect transistor geometry using graphene electrodes defined by electron beam lithography, which allows for controlled electrode geometries. Thermal annealing is found to be a crucial step for successful device operation, ensuring stable electronic transport characteristics.
Article
Chemistry, Physical
Shahjad Ali, Ashima Bajaj, Md. Ehesan Ali
Summary: In this study, the quantum transport properties of graphene nanoribbons were investigated using density functional theory and nonequilibrium Green's function techniques. It was found that zigzag graphene nanoribbons exhibit spin-polarized transmission spectra with spin-filtering efficiency up to 50% in the low-lying ferromagnetic state. By reducing the width of the nanoribbons, higher spin-filtering efficiency can be achieved through the evolution of spin-dependent quantum interference features.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Materials Science, Multidisciplinary
Manato Fujimoto, Mikito Koshino
Summary: This study investigates the edge states of twisted bilayer graphene and their topological origin, revealing a special relationship with the moire pattern and the sliding Chern number. The emergence of these moire edge states is linked with topological charge pumping caused by relative interlayer sliding, demonstrating a bulk-edge correspondence inherent in moire bilayer systems.
Article
Nanoscience & Nanotechnology
Van-Truong Tran, Alessandro Cresti
Summary: The study demonstrates that 90 degrees-bent graphene nanoribbons with nanopores have better thermoelectric performance at high temperatures, and the introduction of nanopores can significantly enhance their thermoelectric capacity. By incorporating a certain number of nanopores, the figure of merit ZT can be effectively improved.
Article
Chemistry, Multidisciplinary
Jian Zhang, Gabriela Borin Barin, Roman Furrer, Cheng-Zhuo Du, Xiao-Ye Wang, Klaus Muellen, Pascal Ruffieux, Roman Fasel, Michel Calame, Mickael L. Perrin
Summary: Bottom-up synthesized graphene nanoribbons (GNRs) are of interest due to their atomically controlled structure and customizable physical properties. However, understanding the relationship between cryogenic charge transport and the number of GNRs in a device is challenging due to lack of precise control over GNR length and location.
Article
Chemistry, Multidisciplinary
Tao Wang, Sofia Sanz, Jesus Castro-Esteban, James Lawrence, Alejandro Berdonces-Layunta, Mohammed S. G. Mohammed, Manuel Vilas-Varela, Martina Corso, Diego Pena, Thomas Frederiksen, Dimas G. de Oteyza
Summary: This study characterized the magnetic states of chiral graphene nanoribbons by substitution of hydrogen atoms with ketones, leading to the generation of unpaired pi radicals that can interact via exchange coupling. The interactions between these radical states were found to depend significantly on factors such as chirality and the presence of ketone functionalization, and the parameters for accurately describing these systems within the mean-field Hubbard model were determined. Overall, this research provides insights for theoretically modeling and designing GNR-based nanostructures with tunable magnetic properties.
Article
Physics, Mathematical
Alessandro Giuliani, Vieri Mastropietro, Marcello Porta
Summary: The study proves the universality of the quadratic response of quasi-particle flow between Weyl nodes in Weyl semimetals, independent of interaction strength and form. This universality demonstrates the non-renormalization property of the chiral anomaly for the infrared emergent description, which is valid in the presence of a lattice and at a non-perturbative level.
COMMUNICATIONS IN MATHEMATICAL PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Gabriela Borin Barin, Qiang Sun, Marco Di Giovannantonio, Cheng-Zhuo Du, Xiao-Ye Wang, Juan Pablo Llinas, Zafer Mutlu, Yuxuan Lin, Jan Wilhelm, Jan Overbeck, Colin Daniels, Michael Lamparski, Hafeesudeen Sahabudeen, Mickael L. Perrin, Jose Urgel, Shantanu Mishra, Amogh Kinikar, Roland Widmer, Samuel Stolz, Max Bommert, Carlo Pignedoli, Xinliang Feng, Michel Calame, Klaus Muellen, Akimitsu Narita, Vincent Meunier, Jeffrey Bokor, Roman Fasel, Pascal Ruffieux
Summary: In this study, the growth, characterization, and device integration of 5-atom wide armchair GNRs were investigated, showing potential for switching behavior at room temperature. The optimized growth protocols successfully bridge between atomic precision control of electronic properties and successful device integration of GNRs.
Article
Materials Science, Multidisciplinary
Mark J. J. Mangnus, Felix R. Fischer, Michael F. Crommie, Ingmar Swart, Peter H. Jacobse
Summary: In this paper, the relationship between the geometry of graphene nanoribbons (GNRs) and their charge transport characteristics is explored through in situ through-transport measurements and the development of a comprehensive transport model. The combined experimental and theoretical efforts help elucidate general charge transport phenomena in GNRs and GNR heterostructures.
Article
Materials Science, Multidisciplinary
S. Ihnatsenka
Summary: This study presents quantum-mechanical calculations of electron magnetotransport in graphene Fabry-Perot interferometers, focusing on the spatial structure of edge channels. For interferometers created by removing carbon atoms, strong interchannel scattering is observed, leading to nonadiabatic electron transport. However, a common Aharonov-Bohm oscillation pattern is observed in two-terminal conductance, independent of crystallographic orientation. The interferometer constrictions host localized states that may affect the device. For interferometers created by electrostatic confinement, adiabatic electron transport is observed, with Aharonov-Bohm interference visible only at certain magnetic field ranges.
Article
Materials Science, Multidisciplinary
P. Schmelcher, B. S. Monozon
Summary: In this study, we present an analytical approach to investigate the multiphoton absorption and Rabi oscillations in armchair graphene nanoribbons (AGNRs) subjected to a time-oscillating electric field induced by a parallel light wave. We employ the two-dimensional Dirac equation for massless electrons confined within the ribbon and derive the explicit expressions for the production rate of electron-hole pairs, the multiphoton absorption coefficient, and the frequency of Rabi oscillations in the resonant approximation. We examine the dependence of these quantities on the ribbon width and electric field strength in both the multiphoton-assisted and tunneling regimes, corresponding to time-oscillating and constant electric fields, respectively. Our results reveal a significant enhancement effect of the oscillating electric field on intersubband transitions. Furthermore, our analytical results are qualitatively consistent with numerical calculations for graphene layers. Estimations of experimental values for commonly used AGNRs and laser parameters suggest that both Rabi oscillations and multiphoton absorption phenomena can be observed in laboratory settings. Moreover, the data related to intersubband tunneling indicates that AGNRs can serve as a one-dimensional condensed matter analog for detecting quantum electrodynamics vacuum decay by applying an external electric field.
Article
Materials Science, Multidisciplinary
Mahnoosh Rostami chayjan, Isa Ahmadi, Farhad Khoeini
Summary: This study proposes a combined modeling of molecular mechanics and the tight-binding approach to investigate the effects of external factors on the electronic transport properties of nanomaterials, focusing on armchair graphene nanoribbons. The presence of vacancy defects in the structure leads to the transition from a metal to a semiconductor phase, with the energy gap size increasing with the number of defects. Adjusting parameters such as the number of defects and magnitude of local forces allows for control of the transport gap of the system, which may have implications for the design of nano-electromechanical systems.
RESULTS IN PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Sepideh Zokaei, Donghyun Kim, Emmy Jarsvall, Abigail M. Fenton, Albree R. Weisen, Sandra Hultmark, Phong H. Nguyen, Amanda M. Matheson, Anja Lund, Renee Kroon, Michael L. Chabinyc, Enrique D. Gomez, Igor Zozoulenko, Christian Muller
Summary: Molecular doping of polythiophene with oligoethylene glycol side chains significantly enhances both the electrical and mechanical properties of the polymer. This doping method influences the glass transition temperature and pi-stacking of the polymer, with multivalent counterions showing little effect on stiffness at comparable oxidation levels. These findings suggest that molecular doping is a powerful tool for designing mechanically robust conducting materials for flexible and stretchable electronics.
MATERIALS HORIZONS
(2022)
Article
Chemistry, Multidisciplinary
Oliya S. Abdullaeva, Ihor Sahalianov, Malin Silvera Ejneby, Marie Jakesova, Igor Zozoulenko, Sara I. Liin, Eric Daniel Glowacki
Summary: A microfabricated ROS modulation device based on controlled faradaic reactions was developed in this research. The device can generate tunable gradients of peroxide and oxygen concentrations, enabling controlled H2O2 delivery. The prototype devices were tested by modulating human H2O2-sensitive channels to demonstrate the potential of PEDOT as an H2O2 delivery system.
Article
Chemistry, Multidisciplinary
Jennifer Y. Gerasimov, Arnab Halder, Abdelrazek H. Mousa, Sarbani Ghosh, Padinhare Cholakkal Harikesh, Tobias Abrahamsson, David Bliman, Jan Strandberg, Matteo Massetti, Igor Zozoulenko, Daniel T. Simon, Magnus Berggren, Roger Olsson, Simone Fabiano
Summary: Organic electrochemical transistors formed by in operando electropolymerization are recognized as a simple and effective implementation of synapses in neuromorphic hardware. This study investigates the interface between the substrate and monomer precursors, showing that monomer adsorption to the substrate increases the effective monomer concentration at the surface. The control of interactions between substrate and monomer precursor is crucial for the growth of polymer films, especially for fabricating synaptic systems on inexpensive, flexible substrates.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Materials Science, Paper & Wood
Jiu Pang, Aleksandar Y. Mehandzhiyski, Igor Zozoulenko
Summary: The study presents a new cellulose nanocrystal (CNC) model based on Martini 3, reproducing experimental measurements and improving upon previous CNC models. Surface modifications and interactions with Na+ ions were investigated, along with the study of colloidal stability with varied NaCl concentrations, showing good agreement with experimental results. This work brings new progress towards CNC modelling for describing different surface modifications and colloidal solutions.
Article
Materials Science, Multidisciplinary
Khalil Chennit, Najmeh Delavari, Samia Mekhmoukhen, Rassen Boukraa, Laure Fillaud, Samia Zrig, Nicolas Battaglini, Benoit Piro, Vincent Noel, Igor Zozoulenko, Giorgio Mattana
Summary: This article presents the first example of inkjet-printed, electrolyte-gated organic field-effect transistors fabricated on flexible polyimide substrates. The performance of inkjet-printed, coplanar devices is compared to those of transistors with a metallic wire gate electrode. Good quantitative agreement is achieved between simulation and experiments, indicating the potential use of NPP simulations as predictive tools for device design and optimization. This study opens up avenues for the development of low-cost, flexible sensors and circuits.
ADVANCED MATERIALS TECHNOLOGIES
(2023)
Article
Materials Science, Multidisciplinary
Sandra Hultmark, Mariavittoria Craighero, Sepideh Zokaei, Donghyun Kim, Emmy Jarsvall, Furqan Farooqi, Sara Marina, Renee Kroon, Jaime Martin, Igor Zozoulenko, Christian Muller
Summary: This study investigates the interplay between the nanostructure, electrical properties, and mechanical properties of a doped polythiophene with oligoether side chains. It is found that the degree of order of the polymer significantly varies with the co-processing of bistriflimidic acid (H-TFSI). The addition of intermediate concentrations of H-TFSI leads to a high degree of pi-stacking, while strongly oxidized material shows structural disorder. The electrical conductivity and Young's modulus increase upon the addition of 4-10 mol% of H-TFSI, but the loss of pi-stacking has a more significant effect on the latter.
JOURNAL OF MATERIALS CHEMISTRY C
(2023)
Article
Physics, Applied
L. Berg, L. Schnorr, L. Merces, J. Bettini, C. C. Bof Bufon, T. Heinzel
Summary: Rolled-up nanomembrane electrodes were used to prepare optically transparent Au/TiO2 Schottky diodes suitable for deep level transient photocapacitance spectroscopy. A rate equation model was used to extract the binding energy and capture cross section of oxygen vacancy from the photocapacitance transients. The obtained values were consistent with those from conventional deep level transient spectroscopy and provided information about the capture process.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Chemistry, Applied
Patrick Heasman, Aleksandar Y. Mehandzhiyski, Sarbani Ghosh, Igor Zozoulenko
Summary: Processing natural cellulose requires dissolution and regeneration. The crystallinity of re-generated cellulose does not match that of native cellulose, and the physical and mechanical properties of re-generated cellulose vary depending on the technique used. Molecular dynamics simulations were performed to simulate the regeneration of order in cellulose. The simulations show that cellulose chains have an affinity to align with each other on the nanosecond scale, but the end results still lack sufficient order. The time factor plays a major role in reclaiming the order of crystalline cellulose.
CARBOHYDRATE POLYMERS
(2023)
Article
Chemistry, Applied
Jiu Pang, Aleksandar Y. Mehandzhiyski, Igor Zozoulenko
Summary: In this study, we used Martini 3 molecular dynamics simulations to investigate the regeneration of cellulose at a scale comparable to experiments. The structural changes and formation of cellulose sheets and crystallites were monitored using X-ray diffraction (XRD) curves. Our results show that the calculated coarse-grained morphologies of regenerated cellulose are transformed to cellulose II, which is in good agreement with experimental observations.
CARBOHYDRATE POLYMERS
(2023)
Article
Chemistry, Physical
Tahereh Sedghamiz, Aleksandar Y. Mehandzhiyski, Mohsen Modarresi, Mathieu Linares, Igor Zozoulenko
Summary: In this paper, a coarse-grained molecular dynamics (MD) model for PEDOT:PSS is developed and used to calculate the diffusion coefficients and ion distribution in the film. The study finds that the diffusion coefficients for Na+ ions in PEDOT-rich and PSS-rich regions are almost the same and are not sensitive to the oxidation level. Based on this and the simulation results, the commonly accepted granular morphological model of PEDOT:PSS is revised to include a network of pores for ion diffusion.
CHEMISTRY OF MATERIALS
(2023)
Article
Chemistry, Physical
Najmeh Zahabi, Glib Baryshnikov, Mathieu Linares, Igor Zozoulenko
Summary: This study develops a computational technique based on ab initio Car-Parrinello molecular dynamics to trace the temporal motion of charge carriers in the conducting polymer PEDOT. The researchers find that at low temperature, the distortion of the charge carrier gradually disappears and reappears near the position of the counterion. At room temperature, the distortion induced by the charge carrier and atomic vibrations are of similar magnitude, making it challenging to track the charge carrier distortion.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Christian Wimmenauer, Thomas Heinzel
Summary: The combination of super-resolution microscopy and spatial statistics (SMSS) is a powerful method to study the spatial correlations between nanoparticles and moving vesicles in cells. It can distinguish different types of motion and provide information about motion limitations and characteristic length scales. This method fills a gap in studying mobile intracellular nanoparticle hosts.
NANOSCALE ADVANCES
(2023)
Article
Nanoscience & Nanotechnology
Aleksandar Y. Mehandzhiyski, Emile Engel, Per A. Larsson, Giada Lo Re, Igor V. Zozoulenko
Summary: Cellulose is a promising alternative to synthetic polymers in the development of sustainable and environmentally friendly materials. However, it cannot be melt-processed like many synthetic polymers. Chemical modification, such as dialcohol cellulose, can improve its thermoplasticity. A molecular dynamics study of dialcohol cellulose nanocrystals with different degrees of modification reveals that stress, interfacial stiffness, hydrogen-bond network, and cellulose conformations during mechanical shearing are highly dependent on the degree of modification, water layers, and temperature. Experimental investigation shows that increasing the degree of modification and/or water content makes the melt processing of dialcohol cellulose easier, which aligns with the conclusions from the molecular modeling.
ACS APPLIED BIO MATERIALS
(2022)
Article
Chemistry, Physical
Mohsen Modarresi, Igor Zozoulenko
Summary: Poly(3,4-ethylenedioxythiophene) : polystyrene sulfonate (PEDOT : PSS) is one of the most important conducting polymers, and its electrical conductivity can be significantly enhanced by solvent treatment and pi-pi stacking.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Scott T. Keene, Viktor Gueskine, Magnus Berggren, George G. Malliaras, Klas Tybrandt, Igor Zozoulenko
Summary: Efficient transport of both ionic and electronic charges in conjugated polymers has enabled a wide range of novel electrochemical devices. This Perspective provides an overview of the fundamental physical processes underlying the operation of mixed conducting polymer devices and highlights recent advances in this field. Challenges in further extending the understanding of MCP-based device operation are identified. A deeper understanding of the elementary processes governing operation in MCPs will drive materials design and device performance advancement.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
