Seznam abstraktů 2023: SEKCE E - POKROČILÉ METODY PŘÍPRAVY A CHARAKTERIZACE NANOSYSTÉMŮ

Nanobiophotonics is an emerging multidisciplinary field. For biological applications, multi-photon or non-linear spectroscopy can offer several advantages over one-photon excitation. Our research aims to explore novel spectroscopic strategies based on multi-photon excitation. In order to overcome low-signal problems, we exploit plasmonics and perform multi-photon spectroscopy in the enhanced local optical fields of gold- and silver nanostructures. The combination of different plasmonics-enhanced two-photon spectroscopic methods provides very efficient ways to multimodal two-photon sensing and imaging. As an example, information on morphological structures and function of biological systems can be combined with chemical information about molecular composition, structure, and interactions, when second harmonic generation and enhanced vibrational spectroscopic tools are combined. A key aspect of this combination is the implementation of spectroscopically multifunctional nanosensors with plasmonic nanoparticles as basic building blocks. Following multi-photon excitation, these sensors deliver information on their environment inferred from a set of multiple surface-enhanced spectroscopic signatures. Examples of different composite nanomaterials and approaches of molecular characterization in situ in complex biosamples and purified compounds will be discussed to illustrate the power of plasmon-enhanced multiphoton spectroscopy.

Ab initio calculations were employed to investigate the effect of Ti vacancies formation on the core electron binding energy shifts in cubic titanium oxynitride (TiON). It was shown, that the presence of a Ti vacancy reduces the 1s electron binding energy of the first N neighbors by ∼0.6 eV and that this effect is additive with respect to the number of vacancies. Hence it is predicted that the Ti vacancy concentration can be revealed from the intensity of the shifted components in the N 1s spectra. A model to quantify the Ti vacancy concentration based on the N 1s signal components intensity ratios was developed and critically appraised by fitting the N 1s region obtained via X-ray photoelectron spectroscopy (XPS) measurements of TiON thin films. Thus, we have unequivocally established that the formation and population of Ti vacancies in cubic TiON thin films can be quantified by XPS.

Raman spectroscopy provides highly specific chemical information making it an excellent tool for analysing the complex composition and structure of 2D materials, it is often one tool amongst the many required to solve complex research challenges. Renishaw has developed the inVia™ microscope to be used in conjunction with other analytical techniques, to collect correlated data and to build a better picture of the science underpinning your samples. In this work we present Raman data collected in conjunction with other techniques such as photocurrent measurements, PL, SEM, AFM, topography measurements, and Rayleigh scattering. It is standard to use Raman mapping/imaging combined with optical microscopy to provide correlated information on samples. However optical imaging does not always give the required contrast for particular samples and often scanning electron microscopy (SEM) or atomic force microscopy (AFM) images are preferred. We demonstrate advances in combined Raman systems including a system allowing simultaneous SEM and Raman image collection from the same sample area, ensuring results are easily obtained, reliable and accurate.
We have combined Raman spectroscopy with AFM microscopy, to demonstrate use of these techniques to analyse ReS2 flakes. We have used Renishaw Eclipse filters to measure low frequency Raman bands and colocalised measurements with a Dimension Edge AFM to attribute these results to layer number.

Phospholipid bilayers (PLB) are a fundamental structural component of biological membranes that surround living cells and organelles within cells. PLBs can be prepared in-vitro, from liposome particles. Liposomes are artificial vesicles that mimic the structure of biological membranes, consisting of one or more phospholipid bilayers surrounding an aqueous compartment. They are widely used in research, drug delivery, and other applications.
Atomic Force Microscopy presents an interesting approach to studying PLBs in-situ, under semi-physiological conditions, without marking or other modifications. However, it is usually used for imaging topography, which can be affected by various effects, such as oxidative stress. However, in this presentation, we would like to present a different way of using AFM microscopy to study the properties of PLB, which is destructive nanoindentation. In this process, a force is applied to the probe, which penetrates through the bilayer structure, and a typical pattern, called a rupture event (RE), is created in the measured force-distance curve. This approach can also be applied to membranes of living organisms such as bacteria and tissue cultures. Compared to standard approaches in force-distance curve processing, which are relatively well-automated, special mathematical approaches need to be developed here.
The processing of the observed force-distance data used by us is based on smoothing splines and estimation of the first derivative of the curve. This allows us to identify the rupture event and to detect corresponding local extrema with sufficient accuracy.

Tellurium belongs to the chalcogens group and is a well-known p-type semiconductor with a small energy bandgap of 0.33 eV at room temperature. These exceptional properties result in high interest of producing tellurium nanostructures and nanoparticles (NPs) for different applications. Laser ablation synthesis (LAS) is a well-known NPs preparation method. During synthesis, contamination is minimized using a pure target and a pure liquid or gas environment. It is regarded as a physical method and studies on LAS involve the preparation of many types of NPs via the utilization of multiple targets and the collection of NPs in the form of a nanopowder or a colloidal solution.
In this work, the ablation by 1064 nm nanosecond laser in liquid was performed in ethanol or acetone environment to avoid tellurium oxidation and production of tellurium dioxide nanoparticles. The target was made of pure tellurium and movement during ablation avoids the formation of deep craters. The second way of NPs synthesis was performed in a gas environment while helium was used as the surrounding and carrier gas. After the ablation of Te target by 266 nm nanosecond laser, the generated NPs were trapped in the organic solvent (acetone). Both methods yielded very pure Te nanoparticles, as confirmed by their analysis of the LDI MS technique. The main fraction of particles around 10 nm with a tendency to rapid aggregation was observed by TEM and AFM. ACKNOWLEDGEMENTS: This work was supported by GA22-07635S, MUNI/A/1301/2022 and MUNI/A1298/2022 projects.

Scattering-type Scanning Near-field Optical Microscopy (s-SNOM) is a scanning probe approach to optical microscopy and spectroscopy bypassing the ubiquitous diffraction limit of light to achieve a spatial resolution below 10 nanometer. s-SNOM employs the strong confinement of light at the apex of a sharp metallic AFM tip to create a nanoscale optical hot-spot. Analyzing the scattered light from the tip enables the extraction of the optical properties (absorption, reflectivity) of the sample directly below the tip and yields nanoscale images simultaneous to mechanical properties. In addition to optical nanoscopy the technology has been advanced to enable hyperspectral, nanoscale Fourier-transform spectroscopy (nano-FTIR) using broadband radiation.
Equipping s-SNOM systems with IR tunable light sources, nanoscale chemical mapping can be performed at time scales of 30-300s per image. Use of material-selective frequencies in the mid-IR spectral range can be exploited to fully characterize biomaterials, polymer blends or phase change polymers with nanometer-scale domains. A broad range of applications of the s-SNOM technology for biological materials, inorganics and 2D materials research, will be presented.

Research investigating the interface between biological organisms and nanomaterials requires nowadays multi-faceted microscopic methods to elucidate the interaction mechanisms and effects. Here we describe novel approach and methodology correlating data from atomic force microscope inside scanning electron microscope (AFM-in-SEM). This approach is demonstrated on samples of bacteria-diamond-metal complexes (E.coli bacteria and chitosan-coated hydrogenated nanodiamonds decorated with silver nanoparticles) that are relevant in current life science research. Microscopic surface topography (AFM) is combined with chemical, material and morphological information (SEM using SE and BSE at varied acceleration voltages) at the same region of interest and processed to create 3D correlative probe-electron microscopy (CPEM) image. We establish novel 3D RGB color image algorithm for merging multiple SE/BSE data from SEM with the AFM surface topography. This provides new information about microscopic interaction of the diamond-metal nanocomposite with the bacteria, not achievable by individual analyses. The methodology of CPEM data interpretation is independently corroborated by further in-situ (EDS) and ex-situ (micro-Raman) chemical characterization as well as by a force volume AFM analysis. We also discuss broader applicability and benefits of the methodology for life science research.

Plasma treatment is an efficient technique for surface modification and functionalization of nanomaterials used across a wide range of applications. Detailing the surface modifications often requires multiple analyses on different samples by separate techniques before combination of the data. True correlation is only possible when the information is acquired from the same region of interest within the same sample analyzed by separate techniques under the same conditions. Here, we provide details of the correlation of AFM data alongside the secondary electron (SE) and back-scattered electron (BSE) emission from SEM analysis obtained from gallium-doped zinc oxide (ZnO:Ga) nanorods exposed to different plasma treatments. The same region of interest was probed to create a Correlative Probe Electron Microscopy (CPEM) image. There was a good correlation between morphological, electronic and chemical information by SEM regimes and topographical profile obtained using AFM from the same region of interest. At the same time, CPEM clearly showed differences between the analyzed materials. ZnO:Ga was composed of smooth nanorods alongside thin hexagonal disk particles. Plasma treatments etched the nanorod structure, leading to rugged shapes and increased roughness of ZnO:Ga surface facettes from approximately 20 nm RMS to 70 nm after hydrogen plasma treatment and 85 nm for oxygen plasma treatment whereas electronic and chemical properties remained homogeneous.

Our world is filled with fascinating materials. Ranging from complex natural materials, for example, brains with their complex neuronal architecture or bones with their complex osteonal architectures to some of the strongest man-made materials like steel with its complex microstructure spanning across a wide range of length scales from several tens of millimeters down to the atomic scale. Materials Research, Life Sciences, Electronics, or Raw Materials research fundamentally involve multiscale challenges. Unique characteristics are observed at each length scale. By connecting micro and nanoscale science to real world application or material development final research goals may be reached in an efficient way with an optimal time to result path. In this process it is vital to be able to make observations seamlessly at different length scales.
A complex material’s challenge to solve lies in the following: - Materials research involves complex microstructures that are three dimensions (3D); - Each length scale macro-to-nano presents a different perspective, a new insight; - Microstructures are Multiscale; - Length scales are connected, i.e. the frame of reference is extremely important; - Properties are tied to the length scale.
Thus, correlative characterization is crucial for understanding the link between structure, property, processing and performance of any material. This is what the ZEISS unique sample in volume analysis workflow has been developed for, and it will be illustrated in the present talk with applications to battery research and electronics.

The behavior and properties of many modern materials highly depend on their structural, mechanical and electrical properties at the nanoscale. AFM with its extreme x-, y-, and z-resolution is nowadays instrumental to understand the properties of a large variety of materials at this scale. Thereto, AFM not only measures the 3D topography of materials but also offers a large suite of measurement modes that allow correlating topography with the respective properties.
With the DriveAFM, Nanosurf recently introduced a new tip-scanning AFM which not only provides high-performance AFM measurements but also impresses with the integration of full system motorization. The CleanDrive photothermal excitation technology provides faster imaging and facilitates new approaches to measure electrical interaction forces. Here, we will show, how the technological advances of the DriveAFM provide ease of use and enable a variety of nano electrical characterization methods. Examples given will include different approaches to perform conductive AFM, Kelvin probe force microscopy (KPFM) and scanning microwave microscopy (SMM). These methods allow a mapping of local conductivity, surface potential, permittivity, charge carrier density and much more.

Magnetic nanoparticles exhibit promising properties regarding their application in medicine and technology. Among them superparamagnetic iron oxide based ones (SPIONs) are of a particular interest. The analysis of their structure and magnetic characteristics can help to tune their properties for their use in the relevant medical application. SPIONs materials prepared with different procedures and with various types of polymer coatings, namely polyethyleneimine as well as cationic and succinyl derivatives of chitosan, were analysed.
X-ray diffraction measurements were performed and the structure of the materials was investigated through the analysis of the diffractograms. From Williamson-Hall plots the size of the nanoparticles as well as the presence of defects were determined. The results show significant presence of defects in the (1,1,1) planes. The average sizes of the iron oxide cores of the nanoparticles varied from 7 nm to 13 nm, for most samples being about 12 nm.
Magnetometry results allowed for determination of superparamagnetic blocking temperature, which varies significantly between the samples: from 50 K up to above 350 K, with both extremes occurring for the polyethylenimine-coated nanoparticles.
In the Moessbauer spectra, magnetite and maghemite phases were detected. Succinyl chitosanic-modified- samples appear to bear more resemblance to maghemite, while samples coated with cationically-modified chitosan are more magnetite-like. Polyethylenimine-coated nanoparticles are found to have the fastest superparamagnetic fluctuations at room temperature, while both kinds of chitosan-coated nanoparticles exhibit the slowest fluctuations. The relation between the selected methods of synthesis and coating of the nanoparticles, and their resulting properties is analysed and discussed.

There are two important parameters to evaluate image quality in transmission electron microscopy: resolution and image contrast. Conventional electron microscopes exhibit high-resolution capabilities, but they encounter challenges in achieving satisfactory image contrast, particularly with specimens composed of light elements like graphene, carbon nanotubes, and fullerene structures (weak-phase objects).
A physical solution to the problem of insufficient image contrast leads to the use of low-energy electrons.
Low voltage transmission electron microscope LVEM5 developed by Delong Instruments is a powerful tool in the field of material science and nanotechnology operating with the low energy of the primary electron beam of approximately 5kV. Such a low accelerating energy of the electrons causes strong scattering of the electrons within the sample, resulting in remarkable image contrast enhancement.
This property of LVEM5 will be shown using various carbon-based materials, the samples typically benefiting from LVEM5‘s high contrast. The unique combination of available regimes TEM, SEM, STEM, and electron diffraction offers comprehensive insights into the samples under examination. Particularly in the case of samples such as graphene-based materials, the correlation through all of the aforementioned modes, TEM, SEM, and electron diffraction, elevates the sample analysis to a higher echelon.

Scanning probe microscopy (SPM) is a powerful tool for imaging materials at the nanoscale. Operating at room temperature allows for observing surface dynamics such as temporal changes and crystal growth, as well as dopant atomic manipulation. However, the thermal effects at room temperature lead to instabilities in the measurement environment. As a result, room-temperature SPM requires longer working hours and more labor-intensive trial-and-error compared to cryogenic SPM.
To address these issues, we present a room-temperature SPM system that incorporates machine learning techniques to optimize for the measurement environment instabilities (i.e. tip change and drift) and automate the measurements. This system utilizes a composite neural network model with three different tasks to extract topography information, including tip and surface conditions, adsorptions on the surface, and atom/defect localization on the lattice unit. Based on the deep learning recognition results, our SPM can be programmed to carry out self-directed experiments instead of requiring an experimenter.
As a demonstration, we use an autonomous dataset acquisition scheme to collect training data on Si(111)-(7×7) surfaces. We then demonstrate the automatic measurement capabilities by performing Si(111)-(7×7) surface STS measurements, which are typically difficult to reliably measure at the atomic level at room temperature. By statistically analyzing large datasets taken via automated measurements, we present a reliable STS measurement method that is possible even in an unstable room temperature environment.

Global installed photovoltaic capacity reached one terawatt and starts to be important component of the energy mix we are using. The market is dominated by silicon wafer-based solar cells. The price per watt-peak decreases drastically and the thin film alternatives suffers from the higher system cost due to lower conversion efficiencies. Is there still a place for silicon thin films or other thin film technologies?
The answer is yes and surprisingly a lot! The so called interdigitated back contacted silicon heterojunction solar cell (IBC SHJ), combining both the thin film and wafer based technology, is the conversion efficiency world record holder with 26.7 %. The record IBC SHJ cell is fabricated by many photolithography steps, not compatible with mass production. Thus straightforward shadow mask technology is developing. In order to check the profiles of ~10 nm thin passivating IBC prepared by shadow masks on rough substrates, Raman spectroscopy based thickness measurement with resolution bellow 0.2 nm was introduced [1]. Raman in combination with AFM tomography is moreover suitable for characterisation of mixed phase amorphous/nanocrystalline ultrathin films. 3D visualisations of high temperature top selective contacts (TOPCON) will be used as an example.
But since the silicon wafer based technology approaches the practical efficiency limit (the theoretical is at ~ 29 %), the only way how to go beyond 30% is combination of two cells in a so called tandem. By doing that the theoretical limit is shifted to over 40 %. Suitable candidates for the second cell accompanying well mastered IBC SHJ cell are halide perovskites. We will discuss the extraordinary properties of this material family [2]. Finally, we introduce a simple semiconductor property dictating the maximal open circuit voltage obtainable with the given material [3]. In this way we can rapidly preselect suitable candidates for top tandem cell. REFERENCES: [1] M. Ledinský, B. Paviet-Salomon, A. Vetushka, J. Geissbühler, A. Tomasi, M. Despeisse, S. De Wolf , C. Ballif  and A. Fejfar: Sci. Rep. 6, 37859 (2016).; [2] De Wolf, S.; Holovsky, J.; Moon, S.-J.; Loeper, P.; Niesen, B.; Ledinsky, M.; Haug, F.-J.; Yum, J.-H.; Ballif, C. J. Phys. Chem. Lett., 5, 1035-1039 (2014).; [3] Ledinsky, M.; Schönfeldová, T.; Holovský, J.; Aydin, E.; Hájková, Z.; Landová, L.; Neyková, N.; Fejfar, A.; De Wolf, S. Temperature Dependence of the Urbach Energy in Lead Iodide Perovskites. J. Phys. Chem. Lett., 10, 1368-1373 (2019).

Nonwoven mats of polymer nanofibers (NFs) are characterized by a high surface area-to-volume ratio, high porosity, and good pore interconnectivity. Their fibrillar structure resembles the extracellular matrix surrounding the cells. Due to their versatility, NFs have evinced great attention as carriers or semipermeable membranes in various applications, e.g., filtration, drug delivery, wound dressings, biosensors, and tissue engineering. The nanofibrous mats can be carriers of drugs, proteins, or micro/nanoparticles, but the surface of nanofibers must be modified for this purpose. We have already demonstrated that plasma-processed polycaprolactone (PCL) mats are perspective materials for constructing artificial tissues or drug delivery systems [1,2,3]. The PCL was selected in these studies because it is a biodegradable polymer used in many FDA-approved surgical implants and drug delivery devices. It has good mechanical properties and long-term stability in vivo. Its adhesion to supporting polypropylene nonwoven textiles can be improved by plasma processing of the polypropylene [4]. This work demonstrates that plasma processing is an efficient method for modifying synthetic polymers to immobilize lignin-based nano or microparticles. We obtained uniform and dense immobilization of lignin nanoparticles on the PCL plasma-processed mats using plasma polymerization in low-pressure capacitively coupled discharge. Surface coverage of the PCL NFs depended on the size of the lignin particles and additives to lignin (boric acid or chitosan). REFERENCES: [1] E. Permyakova et. al, Materials & Design 153 (2018) 60; DOI: 10.1016/j.matdes.2018.05.002.; [2] S. Miroshnichenko et al., Nanomaterials 9 (2019) 637; DOI: 10.3390/nano9040637.; [3] I. Nemcakova et al. Int. J. Mol. Sci. 21 (2020) 9467; DOI: 10.3390/ijms21249467.; [4] L. Janů et al. Polymers 15 (2023) 1686; DOI: 10.3390/polym15071686.

Silicon nanoparticles (Si-NPs) combine the inherent properties of Si such as low toxicity with nano-gained properties such as good mechanical resistance, surface reactivity and efficient light emission. This brings application prospects in fields such as optoelectronics, electronics, and energy storage systems. Currently, Si-NPs with diameter exceeding 100 nanometres can be fabricated using milling or thermal pyrolysis. Fabrication of small Si-NPs, of up to 20 nm, has also been realized through annealing, electrochemical etching, or synthesis in non-thermal plasma (NTP), albeit often at high expense for small-scale production. Conversely, significant challenge lies in the production of Si-NPs with the diameter range of 20 to 100 nanometres. These Si-NPs are not affected by quantum effects, but they find utility in light scattering and battery applications. Therefore, our research focus centred on the synthesis of these “medium-sized” Si-NPs. The flow-through reactor for the NTP synthesis of small Si-NPs is already well-established in our laboratory. For the medium size range, the complex character of synthesis, which relies on a precisely determined balance between the concentration of gases, residence time, plasma density and other less important parameters, makes the upscaling of the system non-trivial. Therefore, we adapted the NTP synthesis process with two consecutive reactors, dividing the synthesis into two stages of crystalline seed formation and secondary growth through seed linking, aggregation and intergrowth using added silane. We report the size distribution and crystalline characteristics of the synthetized Si-NPs. Furthermore, we present preliminary results of Si-NPs used for the anode material in lithium ion batteries, exploring their potential in energy storage applications with galvanostatic measurements.

Two-photon lithography (TPL) stands at the forefront of high-resolution additive manufacturing, offering the capability to fabricate intricate 2D, 2.5D, and 3D micro/nanostructures with sub-micron resolution features. Recent advances in laser technology, electronics, and optics have ushered in a new era for TPL, positioning it as a transformative technology with multifaceted applications. TPL-fabricated components enable unprecedented precision, allowing for the fabrication of precise optical elements which allow high-efficiency control of light. In microelectronics, the sub-micron resolution capabilities of TPL contribute to the development of advanced circuitry, and miniaturized components. Moreover, TPL's prowess extends to micromechanics, enabling the fabrication of miniature mechanical components with unparalleled precision. In the biomedical field, TPL's sub-micron accuracy proves invaluable for creating complex, biocompatible devices with applications ranging from drug delivery systems to tissue engineering scaffolds. This paper presents the IQnano3D, an innovative TPL instrumentation platform that uses a patented method of laser beam control, facilitating ultra-fast writing while preserving ultra-high resolution. This innovative TPL system enables precise and fast additive manufacturing for a wide range of laboratory and semi-industrial applications.

The surface-enhanced Raman spectroscopy (SERS) is a useful complementary technique of the Raman spectroscopy. In this technique, a special SERS substrate is used to provide an extra Raman sensitivity of the examined substance. Due to the used surface plasmonic properties of the substrate, low concentration of molecules can also be detected. In our work, silicon based SERS substrate was fabricated by pulsed laser processing. For the purpose of the final preparation of the substrate, after laser structuring, a thin high purity gold layer was evaporated onto the surface. The formed SERS substrate test goal was to investigate the SERS enhancement using Rhodamine B and Rhodamine 6G solutions. During the Raman measurements, the limit of detection and the calibration curve were determined for the mentioned dyes. Based on the promising results, the SERS enhancement of our investigated SERS substrate was compared with some commercially available products. In the next period, we will compare the amplification of the gold plated surface against the easier-to-produce silver coated one and propose a simple production technique for mass production.

Synthesis and mass spectrometric characterization of various inorganic compounds including tellurium via laser ablation from various pre-cursors is not common but recently it is becoming more and more frequent. Also, characterization and/or analysis of inorganic nano-materials and/or their thin nano-layers is finding wide applications.
Atomization of high-temperature resistant materials via the formation of inorganic clusters of rare materials is becoming a more important technique for the synthesis and characterization of nano-particles, thin nanolayers, and or clusters.
Synthesis of tellurium nanoparticles or fibres and/or composites important in electronics was done. These exceptional properties result in high interest in producing tellurium nanostructures and nanoparticles (NPs) for different applications. Laser ablation synthesis (LAS) is a well-known NPs preparation method. It is regarded as a physical method and studies on LAS involve the preparation of many types of NPs via the utilization of multiple targets and the collection of NPs in the form of a nano-powder or a colloidal solution.
In this work, the ablation by various lasers like Nd:YAG 1064 nm nanosecond laser or nitrogen laser (337 nm) was performed. The target was made of pure tellurium and movement during laser ablation avoids the formation of deep craters. After the ablation of the Te target by second harmonic Nd:YAG laser 266 nm nanosecond laser in a gas environment, the generated NPs can be trapped in the organics solvents.
Concluding, almost any MALDI TOF mass spectrometer can be used for efficient mass spectrometric analysis and/or characterization of metal powders, thin and nano-layers, and/or mixtures via laser desorption ionization and no changes in mass spectrometric instrumentation are needed. Generation of nano-gold clusters, synthesis of gold carbides for highly precise mass calibration, gold selenides, characterization of various nanolayers, and/or nano-composites, and analysis of high-temperature materials like nanodiamonds, metal carbides, etc. is efficient.

The LiteScope 2.5 represents a cutting-edge advancement in atomic force microscopy (AFM). Our innovative microscope is designed for seamless integration into scanning electron microscope (SEM) systems, enabling true correlative multimodal analysis of experimental samples. The AFM-in-SEM technique allows scientists to combine all the advantages of AFM and SEM performance. Therefore, there are three main benefits of the AFM-in-SEM approach: (I) Complex multimodal analysis: The AFM-in-SEM technique enables the combined study of the topography, electrical, mechanical and magnetic properties together with structural characterization, chemical analysis and surface modification. (ii) In-situ measurements: Researchers can perform all the measurements under the controlled atmosphere of the SEM vacuum chamber. (iii) Fast and precise navigation to the area of interest: Using an electron beam, it is possible to quickly find the ultra-fine particle or surface feature and safely navigate the AFM probe to the area of further analysis. To illustrate the remarkable capabilities of the advanced LiteScope 2.5, we present a state-of-the-art measurement output of several techniques: - Atomic Force Microscopy AFM facilitates the acquisition of high-resolution topographical data for diverse samples, achieving an impressive noise floor of approximately 35 picometers; - Conductive AFM C-AFM offers a high-resolution analysis of local conductivity maps of the sample via applying a bias between the sample and the conductive probe; - Magnetic Force Microscopy
MFM delivers high-resolution imaging of the magnetic properties, visualizing the magnetic domains on the sample's surface.
All measurements were performed in-situ with simultaneous utilization of the SEM performance for fast and precise navigation and additional surface modification by focused ion beam (FIB).

Despite the importance of thiorphan as a small molecule with vital biological roles, its interactions with zinc oxide (ZnO) nanomaterials that are prospective in drug delivery and theranostic applications have not yet been sufficiently explored. Here the impact of surface polarity of different ZnO facets on thiorphan adsorption is studied both experimentally by scanning electron microscope (SEM), atomic force microscope (AFM), combined in situ AFM-in-SEM (AFM placed inside of SEM), Raman spectroscopy and angle resolved X-ray photoelectron spectroscopy (XPS) and theoretically by force field molecular dynamics (FFMD) and density functional tight binding simulations (DFTB)1. Polar ZnO surfaces cause the formation of thiorphan nanodots, where the size of the nanodots depends on the direction of dipoles: small (4 nm) nanodots are formed on Zn-face ZnO, while large (25 nm) nanodots are formed on O-face ZnO. Nonpolar ZnO surfaces cause self-assembly into layered nanoislands with characteristic 4 nm layer thickness, which subsequently merge into rigid nanolayers. AFM-in-SEM data shows clear correlation between SE intensity in SEM and layer height in AFM. The self-assembly is shown to be controlled solely by the effect of surface dipole electric field orientation and magnitude, whereas effects of surface chemistry or solution are negligible. The results thus also show a way for controlling the assembly of thiorphan and other molecular nanomaterials for diverse applications. REFERENCE: [1] Ukraintsev, E.; Hematian, H.; Rezek, B. Polarization Controlled Assembly of Ultrathin Thiorphan Nanostructures on ZnO Surface Facets. Langmuir 2023, 39 (5), 1764-1774. https://doi.org/10.1021/acs.langmuir.2c02393.

The process of metal cluster formation and growth via gas aggregation commences with the release of free metal atoms through magnetron sputtering, followed by their coagulation by thermalization precipitation. Investigation of the early stages of nanoparticle formation aims to uncover the significance of atomic dimers, which act as nanoparticle nuclei. To understand the fundamental mechanisms of initiation dimers production, we utilized energy-resolved mass spectrometry and microscopy imaging to observe deposited nanoparticles. In this study, the efficiency of dimer production originating in the discharge gas phase (ArCu+, Ar2+) and dimers preferentially sputtered directly from the target (Cu2+) is examined. Our findings indicate that sputtered Cu2+ dimers, carrying the high energy tail of Thompson distribution, play a crucial role as agents responsible for initiating the formation of cluster nuclei. Furthermore, experiments using Haberland’s cluster source for nanoparticle synthesis confirmed that the population of Cu2+ dimers is directly proportional to the mass transported by the nanoparticles. As a result, the gas aggregation process can be optimized to produce higher nanoparticle yield by the employment of a pulsed discharge, which leads to higher energies of impinging Ar ions and increased sputtering of metal dimers. Furthermore, the efficiency of this process can be expressed and tailored to the metal dimer per watt unit, which holds significance as an economic and environmental factor. ACKNOWLEDGEMENTS: The research was financially supported by the Czech Science Foundation through the project GACR 21-05030K and by the Ministry of Education, Youth and Sports of the Czech Republic through the project “Solid state physics for the 21st century” CZ.02.1.01/0.0/0.0/16_019/0000760.

The influence of an additional magnetic video-pulse on the nuclear spin echo in magnets is studied (on the example of cobalt micropowder and lithium-zinc ferrite) in two cases of its location relative to the second RF pulse, symmetrical and non-symmetrical [1,2]. In the first case, the decrease in the echo intensity is explained by the successive excitation of nuclei that abruptly change their position in the domain wall, and in the second case, due to the anisotropy of the hyperfine field. The effect of domain wall pinning on the dependence of echo signals on the amplitude and duration of a magnetic video-pulse is studied for the first time within the entire NMR spectrum of nuclei in domain walls. ACKNOWLEDGEMENTS: This work was supported by Shota Rustaveli National Science Foundation of Georgia (Grant # FR-22-7899). REFERENCES: [1] T.Gavasheli, G.Mamniashvili, G.Ghvedashvili, T.Gegechkori, “NMR spin-echo study of the domain wall pinning in cobalt micropowders. Proceedings of 2022 IEEE 2nd Ukrainian Microwave Week (UkrMW) 2022 Nov 14 (pp. 405-409). IEEE.; [2] G.I.Mamniashvili, T.O.Gegechkori, “Investigation of the characteristics of domain wall fixation centers in cobalt by the nuclear magnetic resonance method”, J. Appl. Spectrosc. Vol. 89, No. 6, pp. 1076-1079 (2023). https://doi.org/10.1007/s10812-023-01469-y.

The extensive studies in nanoscience in the last decades are dedicated to the development of new protocols for the preparation of nanoparticles (NPs) with controlled size and shape. The dimensions and steric parameters influence the reactivity, catalytic, electrical, and optical properties and define the application of NPs in various fields: catalysis, sensing, medicine, electronics, etc. The combination of the green synthesis approach in the preparation of noble metal NPs, which defines their biocompatibility, environmental, cost, and time efficiency in synthesis, together with the control of optical properties such as near-infrared (NIR) response through the regulation and control of both size and shape, opens new possibilities in nanomedicine to develop new effective drug delivery systems, to improve the selectivity and efficiency of optical photothermal therapy, etc. Protocols for the synthesis of gold NPs using phytochemical plant extracts are one of the most promising ways in the design of biocompatible gold NPs with different shapes.
In this study, we review the recent achievements in the synthesis of gold nanoparticles with different morphologies such as nanotriangles, nanohexagons, nanourchins, and nanoshells using natural polyphenols. We consider previously isolated compounds, such as gallic acid, and rosmarinic acid, as well as whole plant extracts of peppermint, goldenrod, juniper, lemon balm, etc. The results of NIR spectroscopy and transmission electron microscopy studies are discussed. We show the possibility of synthesizing gold NPs with a size below 60 nm with a response in the NIR region by influencing the shape of gold NPs.