Michaela Sojková

Institute of Electrical Engineering of the Slovak Academy of Sciences

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Martin Hulman

Institute of Electrical Engineering of the Slovak Academy of Sciences

ŠC

Š. Chromík

Institute of Electrical Engineering of the Slovak Academy of Sciences

Edmund Dobročka

Institute of Electrical Engineering of the Slovak Academy of Sciences

PŠ

Peter Šiffalovič

Centre for Advanced Material Application of the Slovak Academy of Sciences

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M. Španková

Institute of Electrical Engineering of the Slovak Academy of Sciences

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V. Štrbı́k

Slovak Academy of Sciences

Karol Végsö

Slovak Academy of Sciences

E. Majková

Institute of Physics of the Slovak Academy of Sciences

Lenka Príbusová Slušná

Institute of Electrical Engineering of the Slovak Academy of Sciences

Jana Hrdá

Institute of Electrical Engineering of the Slovak Academy of Sciences

Cooperative Institutions

Slovak Academy of Sciences

Institute of Electrical Engineering of the Slovak Academy of Sciences

Institute of Chemistry of the Slovak Academy of Sciences

Comenius University Bratislava

Slovak University of Technology in Bratislava

Czech Academy of Sciences, Institute of Physics

Institute of Electrical Engineering

Institute of Physics of the Slovak Academy of Sciences

Centre for Advanced Material Application of the Slovak Academy of Sciences

Czech Technical University in Prague

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パルスレーザ蒸着により成長させた極薄MoS_2膜の構造特性に及ぼすGaN/AlGaN/GaN(0001)及びSi(100)基板の影響【Powered by NICT】

Applied Surface Science (2017)

Š. Chromík Michaela Sojková Viliam Vretenár A. Rosová Edmund Dobročka

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Reorientation of π-conjugated molecules on few-layer MoS₂ films

Physical Chemistry Chemical Physics (2020)

Jakub Hagara Nada Mrkyvkova Peter Nádaždy Martin Hodas Michal Bodík

We show that small π-conjugated molecules adopt a lying-down orientation when deposited on few-layer MoS₂ with horizontally oriented layers. In contrast, for vertically aligned MoS₂ layers, DIP molecules are arranged in a standing-up manner.

10.1039/c9cp05728e

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Citations (11)

Tuning the electrochemical properties of NiS₂ 2D-nanoflakes by one-zone sulfurization for supercapacitor applications

Materials Research Express (2023)

Peter Ondrejka Michaela Sojková Valerii Kotok Patrik Novák I. Hotový

Abstract Nickel-based sulfides (particularly NiS 2 ) are regarded as promising materials for highly efficient electrochemical generation and storage devices. The conventional fabrication methods of nanostructured NiS X electrodes involve several complex steps using multiple precursors and techniques. In this paper, the NiS X electrodes are prepared by a plain one-step process of one-zone sulfurization of Ni foam. The evolution of highly electroactive 2D-nanoflakes reliant on sulfurization temperature is studied. Scanning electron microscopy, x-ray diffractometry, and energy-dispersive x-ray spectroscopy confirmed the presence of NiS X (x = 1 and 2) in the prepared structures. A strong dependence of sample morphology and 2D-nanoflakes density on sulfurization temperature was demonstrated. The electrochemical properties of samples were characterized by cyclic voltammetry and electrochemical impedance spectroscopy measurements. Owing to the 2D-nanoflake structure, the NiS 2 showed attractive electrochemical performance, including a high specific capacitance of 648 mF cm −2 and a capacitance retention rate of 90,7% after 3000 cycles. Our study shows that the composition and crystal growth of NiS X can be tuned by reaction temperature during the sulfurization and high perspective of sulfurization in the synthesis of highly electroactive large-scale electrodes for supercapacitors.

10.1088/2053-1591/acdfaa

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Friction control by engineering the crystallographic orientation of the lubricating few-layer MoS2 films

Applied Surface Science (2020)

Michal Bodík Michaela Sojková Martin Hulman M. Ťapajna Martin Truchlý

Surface layer

10.1016/j.apsusc.2020.148328

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Early-stage growth observations of orientation-controlled vacuum-deposited naphthyl end-capped oligothiophenes

Physical Review Materials (2021)

Mathias K. Huss-Hansen Martin Hodas Nada Mrkyvkova Jakub Hagara Peter Nádaždy

We report on the real-time structure formation and growth of two thiophene-based organic semiconductors, $5,{5}^{\ensuremath{'}}$-bis(naphth-2-yl)-$2,{2}^{\ensuremath{'}}$-bi- and $5,{5}^{\ensuremath{'}\ensuremath{'}}$-bis(naphth-2-yl)-$2,{2}^{\ensuremath{'}}$:${5}^{\ensuremath{'}},{2}^{\ensuremath{'}\ensuremath{'}}$-terthiophene (NaT2 and NaT3), studied in situ during vacuum deposition by grazing-incidence x-ray diffraction and supported by atomic force microscopy and photoabsorption spectroscopy measurements on corresponding ex situ samples. On device-relevant silicon dioxide substrates, for both molecules the growth is observed to transition from two-dimensional (2D) layer-by-layer growth to three-dimensional (3D) growth after the formation of a few-molecule-thick wetting layer. The crystal structure of the NaT2 film is considerably more ordered than the NaT3 counterpart, and there is a significant collective change in the unit cell during the initial stage of growth, indicating strain relief from substrate induced strain as the growth transitions from two to three dimensions. In addition, the orientation of the film molecules are controlled by employing substrates of horizontally and vertically oriented few-layer molybdenum disulfide. Both molecules form needle-like crystals on horizontally oriented ${\mathrm{MoS}}_{2}$ layers, while the NaT3 molecules form tall, isolated islands on vertically oriented ${\mathrm{MoS}}_{2}$ layers. The molecules are standing on silicon dioxide and on vertically oriented ${\mathrm{MoS}}_{2}$, but lying flat on horizontally oriented ${\mathrm{MoS}}_{2}$. These results demonstrate the importance of film-substrate interactions on the thin-film growth and microstructure formation in naphthyl-terminated oligothiophenes.

Terthiophene

10.1103/physrevmaterials.5.053402

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Texture of YBCO layer grown on GaN/c-sapphire substrates

Applied Surface Science (2020)

Edmund Dobročka M. Španková Michaela Sojková Š. Chromík

Texture (cosmology)

Pole figure

10.1016/j.apsusc.2020.148718

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Gas sensors based on diamond heterostructures for air quality monitoring

NANOCOM ... (2023)

Michal Kočí Ondrej Szabó Tibor Izsák Michaela Sojková Marcin Godzierz

Currently, great emphasis is placed on air quality and the presence of pollutants, whether on toxic substances (NH3 or CO), substances that reduce the quality of life (CO2) or chemical vapors from industries (acetone or ethanol).Attention is therefore focused on new gas-sensing materials enabling detection even at low (up to room) temperatures with sufficient response and short reaction time.Here, we investigate the suitability of hydrogen-terminated nanocrystalline diamond (H-NCD) films and their heterostructures with molybdenum disulfide (MoS2), graphene oxide (GO), reduced GO (rGO), thiol-functionalized GO (SH-GO), or gold nanoparticles (Au NPs) for gas sensing applications.Electrical properties are measured for oxidizing gas NO2, reducing gas NH3, and chemical vapor of ethanol (C2H5OH), and at temperatures varied from room temperature to 125 °C.All tested gases were used with a concentration of up to 100 ppm.Synthetic air is used as the flushing gas.The measured parameters of the tested sensors are compared, both with each other and with commercial sensors, and subsequently evaluated.In contrast to the individual forms of employed materials with limited response to the exposed gases, the H-NCD heterostructures revealed better sensing properties.In particular, the Au NPs/H-NCD heterostructures revealed a higher response at 125 °C in contrast to H-NCD, MoS2/H-NCD had quite good response even at room temperature and GO/H-NCD revealed high sensitivity to chemical vapor, which further improved for the SH-GO/H-NCD.

10.37904/nanocon.2023.4785

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Facile Two-Step Pvp-Assisted Deposition of Co-Activated Nanosized Nickel Hydroxide Directly on a Substrate for Large-Scale Production of Supercapacitor Electrodes

SSRN Electronic Journal (2022)

Valerii Kotok Peter Ondrejka Miroslav Mikolášek Michaela Sojková Patrik Novák

General principles of hybrid supercapacitor work and knowledge of the Ni(OH) 2 /NiOOH system were used for the conscious elaboration of the electrode formation method. In this method, the self decomposition reaction of nickel ammonia complex for electrode formation was used. Four types of formation were performed, in which polyvinyl pyrrolidone (PVP) solution and electrochemical or chemical activation by cobalt hydroxide were used. In all cases, structures with nanoflakes were formed. It was found that during chemical activation among nanoflakes flower-like particles of Co(OH) 2 were precipitated. It was shown that the presence of PVP during the nickel ammonia complex decomposition suppressed highly branched particles. The absence of highly branched particles increased the capacitive properties of the formed electrode at high current densities. A mechanism that explained the described performance was proposed. Based on the good characteristics of the ready-to-use electrodes and the absence of need for exotic reagents, heating, and simplicity, it was proposed to consider the method as a perspective for large-scale production.

Deposition

10.2139/ssrn.4195345

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Preparation and structural properties of YBCO films grown on GaN/c-sapphire hexagonal substrate

Applied Surface Science (2010)

Š. Chromík P. Gierłowski M. Španková Edmund Dobročka I. Vávra

Auger electron spectroscopy

Diffusion barrier

Cathodoluminescence

10.1016/j.apsusc.2010.03.035

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Improved Gas Sensing Capabilities of MoS₂/Diamond Heterostructures at Room Temperature

ACS Applied Materials & Interfaces (2023)

Michal Kočí Tibor Izsák G. Vanko Michaela Sojková Jana Hrdá

Molybdenum disulfide (MoS2) and nanocrystalline diamond (NCD) have attracted considerable attention due to their unique electronic structure and extraordinary physical and chemical properties in many applications, including sensor devices in gas sensing applications. Combining MoS2 and H-terminated NCD (H-NCD) in a heterostructure design can improve the sensing performance due to their mutual advantages. In this study, the synthesis of MoS2 and H-NCD thin films using appropriate physical/chemical deposition methods and their analysis in terms of gas sensing properties in their individual and combined forms are demonstrated. The sensitivity and time domain characteristics of the sensors were investigated for three gases: oxidizing NO2, reducing NH3, and neutral synthetic air. It was observed that the MoS2/H-NCD heterostructure-based gas sensor exhibits improved sensitivity to oxidizing NO2 (0.157%·ppm–1) and reducing NH3 (0.188%·ppm–1) gases compared to pure active materials (pure MoS2 achieves responses of 0.018%·ppm–1 for NO2 and −0.0072%·ppm–1 for NH3, respectively, and almost no response for pure H-NCD at room temperature). Different gas interaction model pathways were developed to describe the current flow mechanism through the sensing area with/without the heterostructure. The gas interaction model independently considers the influence of each material (chemisorption for MoS2 and surface doping mechanism for H-NCD) as well as the current flow mechanism through the formed P–N heterojunction.

10.1021/acsami.3c04438

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Citations (13)