Article
Materials Science, Ceramics
Paulina Zubrzycka, Marta Radecka, Thomas Graule, Michael Stuer
Summary: Understanding and controlling interparticle interactions in non-aqueous organic slurries is crucial for the formulation of high solid load ceramic green bodies. Metal cation complexes, particularly chromium (III) 2-ethylhexanoate, provide efficient stabilization mechanisms, such as hemi-micelle formation in methyl ethyl ketone-based slurries. Incorporating metal dopant cations complexes could lead to advances in ceramic slurry formulation, especially in additive manufacturing, opening new pathways for future developments. Additionally, the importance of solvation forces is discussed based on the solvent's protic or aprotic character.
CERAMICS INTERNATIONAL
(2021)
Article
Chemistry, Physical
Joao Paulo Damasceno, Ferdinand Hof, Olivier Chauvet, Aldo J. G. Zarbin, Alain Penicaud
Summary: Aqueous dispersions of fullerene C-60 were prepared by oxidizing fulleride solutions in tetrahydrofuran, transferring them to water, and evaporating the solvent. The charged fullerene dispersions in THF exposed to air can produce aqueous fullerene dispersions that are stable for months.
Article
Chemistry, Multidisciplinary
Felix Manger, Philipp Marlow, Karen Fischer, Manuel Noeller, Christian Sprau, Alexander Colsmann
Summary: Organic semiconductor nanoparticle dispersions are effectively stabilized with small amounts of the p-doping agent 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F(4)TCNQ), eliminating the need for surfactants. This concept can be applied to synthesize dispersions from various light-harvesting benzodithiophene-based copolymers. The resulting dispersions are used to fabricate organic solar cells (OSCs) without any detrimental effect on device performance. This approach enables the eco-friendly fabrication of high-efficiency light-harvesting semiconductor-based OSCs by eliminating environmentally hazardous solvents.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Engineering, Electrical & Electronic
Tariq Mahmood
Summary: The adsorption of small gaseous molecules on the center and edges of polycyclic aromatic hydrocarbons was studied using density functional theory calculations. Through benchmarking, a selected functional was chosen for the detailed analysis of different analytes on coronene. The study revealed that the adsorption complexes were stabilized by X-H-t interactions, with dispersion dominating at the center position and electrostatic interactions dominating at the edges. The electronic properties showed high selectivity of coronene for hydrazine.
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
(2023)
Article
Polymer Science
Shuyu Jia, Shangqi Ning, Yuting Leng, Qiufang Jing, Zhongyu Xu, Fuzheng Ren
Summary: Microparticles and amorphous solid dispersions are effective methods for enhancing the dissolution of insoluble drugs, but stability is a concern. In this study, erlotinib microparticles and solid dispersions were prepared using Soluplus as a carrier. The solid-state properties of these two systems were characterized, and it was found that microparticles existed in a metastable crystal form while solid dispersions were amorphous. The presence of hydrogen bond interactions between erlotinib and Soluplus was confirmed. Both erlotinib microparticles and solid dispersions showed improved dissolution profiles, but microparticles exhibited better stability in accelerated stability testing.
Article
Materials Science, Multidisciplinary
Karen Fischer, Philipp Marlow, Felix Manger, Christian Sprau, Alexander Colsmann
Summary: In this study, a scalable high-throughput continuous-flow microfluidic system was used to synthesize surfactant-free organic semiconductor dispersions. The concentration and nanoparticle size of the dispersions can be controlled, and they exhibit high stability.
ADVANCED MATERIALS TECHNOLOGIES
(2022)
Article
Mechanics
Yul Hui Shim, Simon A. Rogers
Summary: Graphene oxide (GO) has gained attention for its unique properties and applications in materials science and engineering, including DIW printing of three-dimensional structures. Understanding the yielding behavior of GO colloids is important for developing efficient and effective printing inks. In this study, the yielding behavior of GO colloids was investigated through oscillatory rheology, and the recoverable and unrecoverable responses were analyzed to determine the storage and dissipation of energies. This study contributes to the understanding of out-of-equilibrium rheological physics and provides guidelines for energy efficiency in soft material printing.
Article
Multidisciplinary Sciences
Wonsik Eom, Eunsong Lee, Sang Hoon Lee, Tae Hyun Sung, Adam J. Clancy, Won Jun Lee, Tae Hee Han
Summary: The study focuses on maximizing torsional strength of fibers by overcoming rheological thresholds of nanocarbon (nanotube/graphene oxide) dopes. The formed fibers exhibit enhanced structure, modified hierarchy, and improved mechanical properties, with potential for hierarchical dimensional hybrids.
NATURE COMMUNICATIONS
(2021)
Article
Chemistry, Physical
Yi-Tao Xu, Joyce Li, Mark J. MacLachlan
Summary: This study demonstrates the first preparation of stable hydrophobic graphene oxide (GO) photonic liquids, which can achieve tunable reflection wavelength in different hydrophobic liquid media with improved stability compared to aqueous GO suspensions. Hydrophobic additives effectively mediate the self-assembly of GO through an entropy-driven depletion mechanism, allowing the production of tunable photonic liquids without adjusting GO concentrations. Additionally, simultaneous reflection of infrared and visible light can be achieved, enabling infrared photonic GO liquids to display visible colors.
NANOSCALE HORIZONS
(2022)
Article
Nanoscience & Nanotechnology
Lucas Luciano Cullari, Tom Masiach, Sivan Peretz Damari, Shani Ligati, Istvan Furo, Oren Regev
Summary: Adding fibrous clay mineral, sepiolite, in water can effectively enhance the dispersion concentration of graphene, maintaining high lateral size dispersion. This method can be applied as cooling liquids for thermal management solutions, resulting in a 26% enhancement in thermal conductivity.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Chemistry, Multidisciplinary
Jaqueline F. Rocha, Leandro Hostert, Martha Lucia M. Bejarano, Roberta M. Cardoso, Matheus D. Santos, Camila M. Maroneze, Mario R. Gongora-Rubio, Cecilia de Carvalho Castro Silva
Summary: Graphene oxide microfibers with controlled shapes and tunable diameters were fabricated using 3D hydrodynamic focusing on a microfluidic device. Subsequent thermal and microwave treatments resulted in reduced graphene oxide microfibers with exceptional electrical properties, enabling the development of ionic liquid-gate field-effect transistors based on graphene derivative microfibers.
Article
Chemistry, Physical
Yulia Kuznetsova, Ilya A. Balyakin, Ivan D. Popov, Bernhard Schummer, Benedikt Sochor, Svetlana Rempel, Andrey A. Rempel
Summary: In this study, two types of stable Ag2S nanoparticle solutions were synthesized using different stabilization mechanisms, one utilizing MPS for steric stability and the other employing Na2S for electrostatic stability. The correlation between stability and nanoparticle parameters was established.
JOURNAL OF MOLECULAR LIQUIDS
(2021)
Article
Optics
M. Rezaei Mirghaed, M. Arshadi Pirlar, M. M. Jahanbakhshian, R. Karimzadeh
Summary: The manipulation of the nonlinear optical response of graphene oxide liquid crystals through a mechanical-hydrodynamical approach has been demonstrated in this study. The experimental results show that increasing the flow rate in the microchannel enhances both linear and nonlinear absorption coefficients, reducing the laser beam transmission through the sample significantly.
Article
Chemistry, Physical
Xiaojie Li, Xin Li, Lan Jiang, Pei Zuo, Yang Zhao, Sumei Wang, Xiaozhe Chen, Misheng Liang, Le Ma
Summary: This study introduces a new method for preparing twin graphene quantum dots by electric-field-assisted temporally-shaped femtosecond laser ablation liquid, achieving control over the crystallinity of GQDs and potential applications in the fields of magnetism, spin transport, or photoluminescence.
Article
Physics, Applied
Chen Yue, Xiaomei Lu, Junting Zhang, Fengzhen Huang, Jinsong Zhu
Summary: In investigating the special electrical phenomena in a graphene/ferroelectric field-effect transistor, it was found that the conductivity of graphene can be influenced by the Au counter electrode and water adsorption, with stronger coupling to the negative surface.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Matej Velicky, Sheng Hu, Colin R. Woods, Peter S. Toth, Viktor Zolyomi, Andre K. Geim, Hector D. Abruna, Kostya S. Novoselov, Robert A. W. Dryfe
Article
Chemistry, Physical
Andrey Krayev, Sergiy Krylyuk, Robert Ilic, Angela R. Hight Walker, Ashish Bhattarai, Alan G. Joly, Matej Velicky, Albert Davydov, Patrick Z. El-Khoury
JOURNAL OF PHYSICAL CHEMISTRY C
(2020)
Article
Chemistry, Physical
Matej Velicky, Alvaro Rodriguez, Milan Bousa, Andrey Krayev, Martin Vondracek, Jan Honolka, Mahdi Ahmadi, Gavin E. Donnelly, Fumin Huang, Hector D. Abruna, Kostya S. Novoselov, Otakar Frank
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2020)
Article
Chemistry, Multidisciplinary
Matej Velicky, Gavin E. Donnelly, William R. Hendren, William J. I. DeBenedetti, Melissa A. Hines, Kostya S. Novoselov, Hector D. Abruna, Fumin Huang, Otakar Frank
ADVANCED MATERIALS INTERFACES
(2020)
Article
Chemistry, Multidisciplinary
Zuzana Vlckova Zivcova, Milan Bousa, Matej Velicky, Otakar Frank, Ladislav Kavan
Summary: Systematic in situ Raman microdroplet spectroelectrochemical characterization of CuSCN prepared on various substrates reveals homogenous CuSCN layers with a thickness of approximately 550 nm. The double-layer capacitance of CuSCN layers varies with different substrates. Changes in CuSCN vibrations at positive potentials indicate a substrate-dependent modification of delocalization on the Cu-S bond.
Article
Chemistry, Multidisciplinary
Wendel S. Paz, Marcos G. Menezes, Nathanael N. Batista, Gabriel Sanchez-Santolino, Matej Velicky, Maria Varela, Rodrigo B. Capaz, Juan Jose Palacios
Summary: Franckeite is a natural superlattice composed of two alternating layers of different composition, which has potential for optoelectronic applications. Its layered nature allows for easy exfoliation into thin heterostructures. The complex chemical composition and lattice structure of franckeite have made it challenging to screen for materials with nontrivial topological properties. Density functional theory calculations predict a quantum phase transition originating from stoichiometric changes in one of franckeite's layers.
Article
Electrochemistry
Marc Brunet Cabre, Aislan Esmeraldo Paiva, Matej Velicky, Paula E. Colavita, Kim McKelvey
Summary: This study investigates how the thickness of transition metal dichalcogenides affects the electrochemical response, finding that the response can be described using an electron tunneling barrier related to the material's band gap.
ELECTROCHIMICA ACTA
(2021)
Article
Chemistry, Physical
Matej Velicky
Summary: Electrolyte gating is a popular choice in 2D materials research due to its ability to induce large charge carrier densities with a fraction of the voltage required by conventional dielectric gating.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Chemistry, Physical
Martin Jindra, Matej Velicky, Milan Bousa, Ghulam Abbas, Martin Kalbac, Otakar Frank
Summary: This study introduces a localized spectroelectrochemical method that addresses the issue of distinguishing processes at the edges/defects from those at the intact basal plane. By comparing the electrochemical and spectral responses of monolayer graphene samples with different levels of disorder, it is discovered that both intact and defective areas contribute to the Raman G band shifts and cyclic voltammetry using the hexaammineruthenium complex. Consequently, two independent electron transfer processes coexist in one sample, but are restricted to defect-free and defect-rich areas, respectively.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Physical
Marc Brunet Cabre, Aislan Esmeraldo Paiva, Matej Velicky, Paula E. Colavita, Kim McKelvey
Summary: This study demonstrates that defects at nanometer and sub-nanometer scales in two-dimensional transition metal dichalcogenides can be detected electrochemically using scanning electrochemical cell microscopy (SECCM). By detecting anomalous electrochemical responses on mechanically exfoliated MoS2, the researchers found that these defects display faster electrochemical kinetics compared to the surrounding sample points. The analysis suggests that the defects are disk-shaped defects or one-dimensional defects with nanometer to sub-nanometer widths. This technique allows for the detection of features below the optical diffraction limit without the need for high-resolution electron microscopy or scanning tunneling microscopy.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Physical
Alvaro Rodriguez, Andrey Krayev, Matej Velicky, Otakar Frank, Patrick Z. El-Khoury
Summary: The interaction between excitons and phonons plays a crucial role in the optical and electronic properties of transition metal dichalcogenides (TMDs). This article introduces a new method called ultralow-frequency tip-enhanced Raman spectroscopy, which allows direct probing of ultralow-frequency and interlayer phonons at the nanoscale. The method was applied to analyze phonons in nanobubbles within TMD heterobilayers, providing insights into the interplay between excitons and interlayer/intralayer phonons.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Physical
Ghulam Abbas, Farjana J. Sonia, Martin Jindra, Jiri Cervenka, Martin Kalbac, Otakar Frank, Matej Velicky
Summary: Electrostatic gating using electrolytes is an effective method for controlling the electronic properties of atomically thin two-dimensional materials such as graphene. However, the relationship between the ionic type, size, concentration, and gating efficiency is complex. We conducted in situ Raman microspectroscopy combined with electrostatic gating using various concentrated aqueous electrolytes to understand these relationships. We found that the ionic type and concentration do not significantly affect the doping rate of graphene in the high ionic strength limit of 3-15 M, and a large proportion of the applied voltage contributes to the Fermi level shift in concentrated electrolytes. We provide a practical overview of the doping efficiency for different gating systems.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Mate Velicky
Summary: Reduction of greenhouse gas emissions is a priority for activists, scientists, and policy makers, and bitcoin mining has the potential to contribute to this goal more than commonly believed. Despite criticism for its inefficiency and electricity consumption, the decentralized nature of the bitcoin network offers opportunities for renewable energy transition. This article discusses the challenges and benefits of incorporating bitcoin mining into the global energy production.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2023)
Article
Materials Science, Multidisciplinary
Satyam Sahu, Golam Haider, Alvaro Rodriguez, Jan Plsek, Martin Mergl, Martin Kalbac, Otakar Frank, Matej Velicky
Summary: This work introduces a novel method for preparing large-area monolayers of various layered materials using gold-assisted exfoliation, followed by their transfer to arbitrary substrates. The quality of the prepared layers and their optical properties are assessed using X-ray photoelectron, Raman, and photoluminescence spectroscopies. Field-effect transistors and photodetectors are then fabricated to demonstrate the suitability of this technique for large-area optoelectronic devices.
ADVANCED MATERIALS TECHNOLOGIES
(2023)
Article
Materials Science, Multidisciplinary
Alvaro Rodriguez, Matej Velicky, Jaroslava Rahova, Viktor Zolyomi, Janos Koltai, Martin Kalbac, Otakar Frank
Summary: This study utilizes a combination of micro-Raman and tip-enhanced Raman spectroscopy, along with ab initio simulations, to reveal the strong interaction between monolayer MX2 and a gold substrate, and provides an interpretation for the Raman spectra of TMDC-based heterostructures.
