PhD disertation themes – how to start?

1. Filip, Peter: Quantum oscillations in external fields

   (Kvantové oscilácie v externých poliach)
   —

   Supervisor: Filip, Peter, Mgr., PhD.

   Contact: peter.filipsavbask

    
2. Gendiar, Andrej: Quantum mechanics in the language of tensor networks

   (Kvantová mechanika v jazyku tenzorových sietí)
   —

   Supervisor: Gendiar, Andrej, Mgr., PhD.

   Contact: andrej.gendiarsavbask

   Goals:
   

   Properties of tensor-network states are investigated by the entanglement entropy in quantum spin models.

   Annotation:
   

   The tensor-product states (TPS) are frequently used in modern physics in order to obtain energies and eigenstates of quantum models. The typical systems to be studied are spin models whose Hamiltonians describe magnetism at zero temperature. By means of the tensor-product states, a quantum wave function (eigenstate) is approximated. The wave function contains both the physical degrees of the freedom, describing the Hilbert space, and the auxiliary (non-physical) degrees of the freedom, whose size controls range of the correlations, i.e., the accuracy. Many-body interacting spin systems are to be characterized by the TPS at the phase transition be means of the quantum entanglement. Since it is a non-trivial task, being non-analytically solvable, numerical approaches can be used, in particular, an arbitrary programming language can be freely applied, e.g., Python, MatLab, C++, etc. Novel alternative methods based on the tensor networks are to be proposed, which will originate in the renormalization techniques.

    
3. Kalinay, Pavol: Dimensional reduction of evolution equations in space constrained systems

   (Dimenzionálna redukcia evolučných rovníc v priestorovo obmedzených systémoch)
   —

   Supervisor: Kalinay, Pavol, RNDr., CSc.

   Contact: pavol.kalinaysavbask

    
4. Nagaj, Daniel: Quantum Hamiltonian complexity

   (Kvantová hamiltonovská komplexnosť)
   —

   Supervisor: Nagaj, Daniel, Mgr., PhD.

   Contact: daniel.nagajsavbask

    
5. Nagaj, Daniel: Quantum optimization

   (Kvantová optimalizácia)
   —

   Supervisor: Nagaj, Daniel, Mgr., PhD.

   Contact: daniel.nagajsavbask

    
6. Plesch, Martin: Thermodynamics of quantum particles

   (Termodynamika kvantových častíc)
   —

   Supervisor: Plesch, Martin, RNDr., PhD.

   Contact: martin.pleschsavbask

   Goals:
   

   The aim to analyze thermodynamical properties of ansanbles of quantum particles

   Annotation:
   

   Quantum particles exhibit different collective properties in comparison to classical ones. Indiscriminability in connection with the existence of two fundamental species (fermions and bosons) lead to many peculiar and interesting results. The aim of the thesis is to investigate these affects and their influence on thermodynamical properties in mesoscopic systems, such as cells.

    
7. Plesch, Martin: Benchmarking of quantum computers

   (Benchmarking kvantových počítačov)
   —

   Supervisor: Plesch, Martin, RNDr., PhD.

   Contact: martin.pleschsavbask

   Goals:
   

   The aim ist o test and benchmark quantum computer accessible via cloud.

   Annotation:
   

   Small scale quantum computing has recently seen a large development, with IBM making their quantum processors accessible via cloud. With this step, quantum experiments on real quantum hardware became accessible to theorist all over the world. Additionally, other companies (e. g., Rigetti and Alibaba) are working on similar projects and their own quantum processors are becoming available to general public.

   Within th ework we will test quantum computers on protocols that have the potential to ba applicable also on small number of qubits, such as Variational Quantum Eigensolver.

    
8. Šamaj, Ladislav: Statistical mechanics of Coulomb systems

   (Štatistická mechanika coulombovských systémov)
   —

   Supervisor: Šamaj, Ladislav, RNDr., DrSc.

   Contact: ladislav.samajsavbask

    
9. Ziman, Mário: Quantum information structures in space-time

   (Kvantovo-informačné štruktúry v priestoročase)
   —

   Supervisor: Ziman, Mário, doc. Mgr., PhD.

   Contact: mario.zimansavbask

    
10. Ziman, Mário: Operational quantum thermodynamics

    (Operačná kvantová termodynamika)
    —

    Supervisor: Ziman, Mário, doc. Mgr., PhD.

    Contact: mario.zimansavbask

     
11. Ziman, Mário: Quantum verification methods

    (Kvantové verifikačné metódy)
    —

    Supervisor: Ziman, Mário, doc. Mgr., PhD.

    Contact: mario.zimansavbask

     
12. Ziman, Mário: Optimalisation of higher-order quantum structures

    (Optimalizácia kvantových štruktúr vyšších rádov)
    —

    Supervisor: Ziman, Mário, doc. Mgr., PhD.

    Contact: mario.zimansavbask

     
13. Ziman, Mário: Quantum network communication and security

    (Komunikácia a kryptografia v kvantových sieťach)
    —

    Supervisor: Ziman, Mário, doc. Mgr., PhD.

    Contact: mario.zimansavbask

     

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1. Boháč, Vlastimil:

   (Vývoj jednosondových senzorov a metód na vyšetrovanie tepelných vlastností materiálov)
   —

   Supervisor: Boháč, Vlastimil, Ing., CSc.

   Contact: vlastimil.bohacsavbask

    
2. Boháč, Vlastimil:

   (Vyšetrovanie termofyzikálnych vlastností poréznych materiálov pri simultánnom transporte tepla a vlhkosti)
   —

   Supervisor: Boháč, Vlastimil, Ing., CSc.

   Contact: vlastimil.bohacsavbask

    
3. Butvinová, Beata:

   (Vplyv špecifických vlastností povrchov kovových pások na ich magnetické vlastnosti)
   —

   Supervisor: Butvinová, Beata, RNDr., CSc.

   Contact: beata.butvinovasavbask

    
4. Gmucová, Katarína: Charge transport at the nanocomposite thin film / electrolyte interface

   (Transport náboja na rozhraní nanokompozitných vrstiev s elektrolytom)
   —

   Supervisor: Gmucová, Katarína, RNDr., CSc.

   Contact: katarina.gmucovasavbask

   Annotation:
   

   The thesis will be oriented toward the analysis of charge transfer phenomena at a nanocomposite thin film / electrolyte interface. Organic semiconductor based composites with embeded nanoparticles will be studied. A comprehensive understanding of the charge transfer kinetics at thin film / electrolyte interface is a key to developing both the prospective solar cells and electrochemical sensors based on electrochemical and combined electrochemical and optical signal transduction and readout. The complex analysis of charge transfer kinetics at nanocomposite thin films will contribute to the elucidation of anomalous charge transfer origin at nanostructured interfaces and to finding the chances of its applications in photovoltaics and sensorics.

    
5. Krajčí, Marián:

   (Počítačové modelovanie nanoštruktúr na povrchoch kovov)
   —

   Supervisor: Krajčí, Marián, RNDr., DrSc.

   Contact: marian.krajcisavbask

   Annotation:
   

    
6. Krajčí, Marián:

   (Katalýza chemických reakcií na povrchoch kovov)
   —

   Supervisor: Krajčí, Marián, RNDr., DrSc.

   Contact: marian.krajcisavbask

    
7. Lányi, Štefan:

   (Analýza dielektrických a polovodičových tenkých vrstiev na nanometrovej úrovni)
   —

   Supervisor: Lányi, Štefan, Ing., DrSc.

   Contact: stefan.lanyisavbask

    
8. Maťko, Igor: Thermoanalytical and microstructural characterization of phase behavior of cryoprotective mixtures and lipid bilayer

   (Termoanalytická a mikroštruktúrna charakterizácia fázového správania v systémoch kryoprotektívna zmes a lipidová dvojvrstva)
   —

   Supervisor: Maťko, Igor, RNDr., CSc.

   Contact: igor.matkosavbask

   Goals:
   

   General aim of the study is to clarify processes of solidification and melting of cryoprotective mixtures with relevance for cryopreservation of cells and biological tissues.
   
   The study comprises an analysis of phase behavior of cryoprotective mixtures in bulk and in soft confinement of liposome. Another studied aspect is an effect of cryoprotective mixtures composition upon phase transitions of lipid bilayer.

   Annotation:
   

   Cryoprotective mixture is a substance that allows the conservation of biological preparations by means of frost fixation (the so-called cryopreservation). The work will focus on mixtures whose active component (cryoprotectant) is dimethylsulfoxide (DMSO). The mechanism of action of such a mixture in the process of freezing biological material is still poorly understood. It is known that the viability of biological material is markedly non-linear (stepwise) depending on the concentration of cryoprotectant in the mixture, but its value must be kept as low as possible due to the toxicity of DMSO alone. A model system for studying the cryopreservation mechanism will be a sample of a known cryoprotective mixture / liposome composition. The cryoprotective composition in this system is a liquid found in part in the so-called confined state by a liposome matrix. Liquids in such a state often exhibit different behavioral characteristics from the bulk state.

   The experimental characterization of the system will mainly consist of:

   • Thermal analysis by differential scanning calorimetry (DSC),
   • Microstructure analysis (monitoring of free volume changes) by means of positron annihilation spectroscopy (PALS), performed in close cooperation.

    
9. Mihalkovič, Marek: Search for and optimization of novel low-temperature structures

   (Vyhľadávanie a optimalizácia nových nízkoteplotných atómových štruktúr)
   —

   Supervisor: Mihalkovič, Marek, RNDr., CSc.

   Contact: marek.mihalkovicsavbask

   Annotation:
   

   Formulation of the problem is simple: given a set of chemical species, predict atomic structures they will form (at zero or finite temperature). Partial, yet critical steps in this process are search for energy-minimizing structures at given fixed chemical composition, or simpler, given the constraint of fixed numbers of atoms of each specie inside periodic cell. Even the latter, easiest problem is nowadays only solvable for up to several tens of atoms. This project will not focus on further development of the general methods, but rather adapt the current methods to selected challenging situations, when the expected optimal structrures have complex, hierarchical architecture.

   The succesful applicant will use a range of methods, starting from ab-initio quantum-mechanical calculations as implemented for example in widely used package VASP, through classical molecular dynamics and/or simulated annealing schemes using empirical interactions, to methods/algorithms for efficient searches through cohesive energy landscapes like genetic algorithm. The expected outcome of this postgraduate study will be prediction of novel complex atomic structures, and understanding of their formation mechanism.

    
10. Nádaždy, Vojtech: Electrical and structural properties of perovskite and organic semiconductors for photovoltaics

    (Elektrické a štruktúrne vlastnosti perovskitov a organických polovodičov pre fotovoltiku)
    —

    Supervisor: Nádaždy, Vojtech, Ing., CSc.

    Contact: vojtech.nadazdysavbask

    Goals:
    

    Efficiency and stability increase of perovskite and organic solar cells.

    Annotation:
    

    Perovskite solar cells (PSCs) are one of the “hot topics“ in contemporary research in the 3rd generation photovoltaics. The PhD theme is focused on the preparation of perovskite and organic semiconductor layers utilized in PSCs and their systematic investigation from the point of view of the electronic structure, crystallographic structure, morphology, and interface properties. Electronic structure of the layers will be investigated with the novel energy-resolved electrochemical impedance spectroscopy developed recently in our laboratory. Basic parameters of PSCSs such as the open-circuit voltage, short-circuit current, fill factor and power conversion efficiency will be analyzed as well. Original knowledge on correlation between the electronic structure, electronic transport properties and interface quality is expected.
    The work will be realized at the Institute of Physics, SAS.

     
11. Štich, Ivan: Study of nanostructures on strongly ionic surfaces and their charge manipulation

    (Štúdium nanoštruktúr na silne iónových povrchoch a ich nábojóvá manipulácia)
    —

    Supervisor: Štich, Ivan, prof. Ing., DrSc.

    Contact: ivan.stichsavbask

    Goals:
    

    Make use of computer modeling (primarily DFT) for understanding of formation and charge states of different nanostructures (oxygen atoms, pairs of oxygen atoms, oxygen molecules: peroxide and superoxide, gold clusters) on strongly ionic surfaces (TiO2, for instance) and tie them up with experimental AFM/KPFS results obtained by our partners at the Osaka University.

    Annotation:
    

    he project capitalizes on strong experiment-theory synergies, where the present project is in charge of the theory part and our partners at the Osaka University of the experimental part. Ionic surfaces, such as TiO2, form numerous atomic defects (oxygen and hydrogen defects, Ti interstitials) which form charged quasi-particles, polarons [1], which play a key role in formation of different nanoparticles (oxygen atoms, pairs of oxygen atoms, oxygen molecules: peroxide and superoxide, gold clusters) [1,2] on the surface. The nanoparticles are charged due to charge transfer to/from polarons as well as by KPFS nanomanipulation of charge by electron tunneling from/to the AFM tip. The project currently deals mainly with gold clusters on TiO2. These nanosytems and the associated charge-transfers will be studied by DFT methods and the results will be correlated with experimental AFM/KPFS results. The main project output will be publications in high-impact journals. The PhD. student will make a visit at our partner’s laboratories in Osaka and at the KCL, London.

    References:
    

    [1] Q. Zhang, Y.J. Li, H. F. Wen, Y. Adachi, M. Miyazaki, Y. Sugawara, R. Xu, Z. H. Cheng, J. Brndiar, L. Kantorovich, and I. Štich, Measurement and Manipulation of the Charge State of an Adsorbed Oxygen Adatom on the Rutile TiO2(110)-1×1 Surface by nc-AFM and KPFM,
    J. Am. Chem. Soc. 140, 15668 (2018).
    [2] Y. Adachi, H.F. Wen, Q.Z. Zhang, M. Miyazaki, Y. Sugawara, H. Sang, J. Brndiar, L. Kantorovich, I. Štich, and Y.J. Li, Tip-Induced Control of Charge and Molecular Bonding of Oxygen Atoms on the Rutile TiO2 (110) Surface with Atomic Force Microscopy, ACS Nano 13, 6917 (2019).

     
12. Štich, Ivan: Computational many-body study for electronic and photonic properties of 2D systems

    (Modelovanie elektrónových a fotonických vlastností 2D systémov počítačovými many-body technikami)
    —

    Supervisor: Štich, Ivan, prof. Ing., DrSc.

    Contact: ivan.stichsavbask

    Goals:
    

    Development and application of computational many-body techniques (primarily QMC- Quantum Monte Carlo) for ultra-accurate modeling of electronic and photonic properties of 2D systems (for instance optical and quasi-particle band gap, excitonic binding energies, etc.) Make use of this expertise for calculation of electronic-photonic properties of 2D systems under applied strain.

    Annotation:
    

    The project deals with development and application of computational many-body techniques (primarily QMC- quantum Monte Carlo) for ultra-accurate modeling of electronic and photonic properties of 2D systems. 2D systems have already revolutionized science, and have the potential to revolutionize also technology. In spite that, accurate determination of their electronic and photonic properties (for instance optical and quasi-particle band gaps, excitonic binding energies, etc.) is still a challenge. Customary techniques (DFT, GW, for instance) usually yield band gaps with errors of 1eV [1], rendering them of little use. Recently, we have shown, how these deficiencies can be eliminated using stochastic quantum Monte Carlo methods [1]. The PhD. student will engage in further development and application of QMC methods to 2D systems, primarily 2D systems under applied strain. It has been shown that strain is a very effective tool for tuning electronic properties of 2D materials [2]. The PhD. student will collaborate also with our partners at the North Carolina State University and at the University of Regensburg.

    References:
    

    [1] T. Frank, R. Derian, K. Tokár, L. Mitas, J. Fabian, and I. Štich, Many-Body Quantum Monte Carlo Study of 2D Materials: Cohesion and Band Gap in Single-Layer Phosphorene, Phys. Rev. X 9, 011018 (2019).
    [2] K. Tokár, J. Brndiar and I. Štich, Raman Activity of Multilayer Phosphorene under Strain, ACS Omega 4, 22418 (2019).

     
13. Švec, Peter: Multilayered and pseudobulk metallic glasses prepared by rapid quenching of the melt

    (Viacvrstvové a pseudoobjemové kovové sklá pripravené rýchlym ochladením taveniny)
    —

    Supervisor: Švec, Peter, Ing., DrSc.

    Contact: peter.svecsavbask

    Annotation:
    

    Analysis and selection of perspective chemical composition for systems of multilayered and pseudobulk metallic glasses derived from Fe and Co-based systems with enhanced glass forming ability.

    Development of methods of preparation of metallic glasses with increased thickness, preparation of metallic glasses with classical and enhanced thickness by planar flow casting. Development of alternative methods of preparation of pseudobulk metallic glasses.

    Analysis of structure and properties of as-quenched systems, analysis of the evolution of structure upon transition from as-quenched metastable state, comparison with classical metallic glasses. Assessment of glass-forming ability with respect to chemical composition and preparation technology.

     
14. Švec, Peter: Bulk metallic glasses prepared by rapid quenching of the melt

    (Objemové kovové sklá pripravené rýchlym ochladením taveniny)
    —

    Supervisor: Švec, Peter, Ing., DrSc.

    Contact: peter.svecsavbask

    Annotation:
    

    Analysis and selection of perspective chemical composition for systems of bulk metallic glasses derived from Fe-based systems with enhanced glass forming ability.

    Development of methods of preparation of metallic glasses with increased thickness, preparation of metallic glasses with classical and enhanced thickness by planar flow casting and by cold-mould casting. Development of alternative methods of preparation of bulk metallic glasses.

    Analysis of structure and properties of as-quenched systems, analysis of the evolution of structure upon transition from as-quenched metastable state, comparison with classical metallic glasses. Assessment of glass-forming ability with respect to chemical composition and preparation technology.

     
15. Švec, Peter: Formation of nanostructures and physical properties of metastable Fe and Co-rich systems

    (Vznik nanoštruktúr a fyzikálne vlastnosti metastabilných systémov bohatých na Fe a Co)
    —

    Supervisor: Švec, Peter, Ing., DrSc.

    Contact: peter.svecsavbask

    Annotation:
    

    Preparation, structure analysis and properties of Fe and Co-rich metallic systems containing suitable glass-forming and nanocrystal-forming elements (e. g. Nb, Cu, B, P, C, etc.) prepared by rapid quenching from the melt in metastable (amorphous) state.

    Analysis of thermodynamics and kinetics of structure evolution during transformation from metastable state; formation of nanocrystalline phases.

    Systematic optimization of composition and thermal treatment of selected systems with the aim of attaining appropriate combinations of magnetic and mechanical properties.

    Correlation of short-range ordering in as-prepared state with the local structure of phases formed during transformations and with the kinetics of their formation. Interpretation of the processes controlling phase transformations from disordered metastable state on atomic level.

     

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1. Majková, Eva: Plasmonic nanoparticles for biomedical applications

   (Plazmonické nanočastice pre biomedicínske aplikácie)
   —

   Supervisor: Majková, Eva, RNDr., DrSc.

   Contact: eva.majkovasavbask

   Goals:
   

   Research of the properties of plasmonic nanoparticles for application of the photothermal effect in biomedicine

   Annotation:
   

   The work is focused on the preparation and studies of the nanoparticles that exhibit surface plasmon resonance (SPR) effect in NIR region. Such nanomaterials functionalized by suitable biomolecules for targeted internalization in cancer cells are important for the application of photothermal effect to the treatment of cancer cells. The research will be focused on the nanoparticles with low toxicity and strong SPR effect to achieve high efficiency of the photothermal effect and selectivity to cancer cells based on the antibody-antigen interaction.

   The work will be performed at the Institute of Physics SAS. The Institute has all necessary technologies and  diagnostics at disposal. The PhD. student will obtain universal skills with the latest experimental methods for the preparation and investigation of nanomaterials and will be actively engaged in an intense collaboration within the framework of several projects.

   References:
   

   1. Minho Kim, et al., Adv. Sci. 2019, 1900471

    
2. Majková, Eva: Perovskite quantum dots for efficiency and stability enhanement of perovskite solar cells

   (Perovskitové kvantové bodky pre zvýšenie účinnosti a stability perovskitových solárnych článkov)
   —

   Supervisor: Majková, Eva, RNDr., DrSc.

   Contact: eva.majkovasavbask

   Goals:
   

   Interface engineering of the perovskite solar cells by perovskite quantum dots

   Annotation:
   

   The work is focused on the preparation and studies of the properties of ordered layers of perovksite quantum dots and their incorporation into the structure of the perovskite solar cell (PSC). Perovskite quantum dots will form an interlayer at the  perovskite-charge transport layer interface and/or they will be embedded directly in the perovskite layer. The research will be focused on the effect of the perovskite quantum dots incorporated in the structure of the perovskite solar cell on its efficiency and long-term stability .

   The work will be performed at the Institute of Physics SAS. The Institute has all necessary technologies and  diagnostics at disposal. The PhD. student will obtain universal skills with the latest experimental methods for the preparation and investigation of nanomaterials and will be actively engaged in an intense collaboration within the framework of several projects.

   References:
   

   1. R. Subair et al, Effect of the doping of PC61BM electron transport layer with carbon nanodots on the performance of inverted planar MAPbI3 perovskite solar cells, Solar Energy 189 (2019) 426-434
   2.M. Cha, P. Da, J. Wang, W. Wang, Z. Chen, F. Xiu et al., Enhancing Perovskite Solar Cell Performance by Interface Engineering Using CH3NH3PbBr0.9I2.1 Quantum Dots, J. American Chem. Soc. 138 (2016) 8581-8587. doi:10.1021/jacs.6b04519.
   3. S. Akin, Y. Altintas, E. Mutlugun, S. Sonmezoglu, Cesium lead based inorganic perovskite quantum-dots as interfacial layer for highly stable perovskite solar cells with exceeding 21% efficiency, Nano Energy. 60 (2019) 557-566. doi:10.1016/j.nanoen.2019.03.091

    
3. Šiffalovič, Peter: In-operando diagnostics of Li batteries

   (In-operando diagnostika Li batérií)
   —

   Supervisor: Šiffalovič, Peter, Dr. Rer. Nat., PhD.

   Contact: peter.siffalovicsavbask

   Goals:
   

   Study of charging/discharging cycles of Li-based batteries by means of X-ray scattering

   Annotation:
   

   We will employ in-operando X-ray scattering studies to follow charging/discharging processes in Li-based batteries. We will focus on Li/S and Li/Si batteries due to their highest available capacity. Utilizing wide- and small-angle X-ray scattering we will track the phase and particle size changes during Li-ion intercalation, respectively. Complementary to X-ray scattering, we will use cyclic voltammetry to track the charging/discharging processes. The work will be realized at the Institute of Physics, SAS.

   References:
   

   1. J. Nelson, et al., J. Am. Chem. Soc. 134, 14 (2012) 6337-6343

    
4. Šiffalovič, Peter: Study of Few-Layer Thin Film Growth by In-Situ X-ray Scattering

   (Štúdium rastu tenkých vrstiev pomocou in-situ RTG rozptylu)
   —

   Supervisor: Šiffalovič, Peter, Dr. Rer. Nat., PhD.

   Contact: peter.siffalovicsavbask

   Goals:
   

   Study of Few-Layer Thin Film Growth by In-Situ X-ray Scattering

   Annotation:
   

   The work will be focused on the kinetics of few-layer thin-film growth, including MoS2, PtSe2 and similar. To elucidate the kinetics of thin-film growth, in-situ grazing-incidence wide-angle X-ray scattering (GIWAXS) setup adapted to a CVD chamber will be used in a laboratory. Complementary GIWAXS experiments will be conducted at synchrotrons in Grenoble (ESRF) and Hamburg (DESY). The work will be realized at the Institute of Physics, SAS.

   References:
   

   1. M. Sojkova, et al., RSC Advances 9 (2019) 29645 - 29651

    

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1. Běták, Emil:

   (Predrovnovážna emisia klastrov zo sférických a deformovaných jadier s uvážením spinových premenných)
   —

   Supervisor: Běták, Emil, doc. RNDr., DrSc.

   Contact: emil.betaksavbask

    
2. Filip, Peter:

   (Kvantové oscilácie častíc v hadrónovej hmote)
   —

   Supervisor: Filip, Peter, Mgr., PhD.

   Contact: peter.filipsavbask

    
3. Gmuca, Štefan:

   (Štruktúra kompaktných hviezd)
   —

   Supervisor: Gmuca, Štefan, Ing., CSc.

   Contact: stefan.gmucasavbask

    
4. Šauša, Ondrej:

   (Pozitrónium v kryoprotektívach vhodných pre depozit živých buniek pri nízkych teplotách)
   —

   Supervisor: Šauša, Ondrej, RNDr., CSc.

   Contact: ondrej.sausasavbask

    
5. Šauša, Ondrej: Creation of positronium and study of crosslinking processes in new organic materials

   (Tvorba pozitrónia a štúdium procesov sieťovania v nových organických materiáloch)
   —

   Supervisor: Šauša, Ondrej, RNDr., CSc.

   Contact: ondrej.sausasavbask

   Goals:
   

   • Determination of temperature dependence of lifetime and intensity of Ps formation in bulk samples of dimethacrylate- and epoxide-based polymers after curing. Determination of local free volume changes over a wide temperature range of 20-300 K.
   • Comparison of microstructural parameters from annihilation measurements with the properties of studied substances by standard techniques such as DSC, DMTA, NIR.
   • Monitoring of changes in positronium formation over time during cross-linking processes, comparison with results of standard techniques (dielectric spectroscopy, NIR, DSC, EPR). Monitoring of various physicochemical effects on the evolution of crosslinking (composition, temperature, lighting).
   • Comparison of positronium formation in bulk and confined state in matrices with nanometer-size pores for selected matrix types and selected organic materials.

   Annotation:
   

   Study of microstructure changes in new organic materials based on dimethacrylates and epoxides in the processes of cross-linking by positron annihilation. The formation of positronium (bound state of e- and e+, Ps) as well as the lifetime of its triplet state (o-Ps) strongly depends on the structure of the material and allows (using appropriate models) to determine cavity sizes in the substance, such as intermolecular voids or pores in nanostructures in the range of 0.1-50 nm. Through changes in local free volume due to controlled changes in physical parameters (temperature, pressure, time), solidification, melting or aging evolutions in the investigated substances will be monitored. In this way, we can also observe the cross-linking processes (the evolution of the chemical reaction) in the formation of polymers and look for connections between the microstructure and the macroscopic properties of the studied substances. The effect of confinement selected organic materials in nanopores of suitable matrices on the physical properties of the confined substances by positron annihilation will be investigated.

    
6. Venhart, Martin: Studies of the nuclear structure using beam from the tandem accelerator

   (Štúdium jadrovej štruktúry pomocou zväzkov z tandemového urýchľovača)
   —

   Supervisor: Venhart, Martin, Mgr., PhD.

   Contact: martin.venhartsavbask

   Goals:
   

   • Performing of experimetns in Tandetron Laboratory in Piešťany
   • Studies of nuclear structure in the vicinity of Z = 28 closed shell
   • Identification of weak decay paths

   Annotation:
   

   Atomic nuclei exhibit shapes that may not be spherical. This has been known since ideas from the 1930’s. First hints of multiple shapes in a single nucleus were proposed in the mid 1950’s. Evidence for multiple shapes in nuclei has progressively built up but it is only recently that it has been realized multiple shapes may occur in a widespread manner. However, multiple shapes generally meant two shapes. There have been only a few examples where more than two shapes have been suggested. In a very recent study, based on detailed spectroscopic study and supporting state-of-the-art theory, multiple shapes are indicated in nuclei that were thought to be very well understood. This identification was based on the on the discovery of previously unknown, very-weak decay paths. Therefore, the ultra-high statistics studies are needed to identify such transitions. Such experiments are nowadays possible only in nuclei located at, or near the stability and long running times are required. Therefore, such a program is very well suited for the small-scale laboratories. Several months of the beam time can be used there. Such a long experiment would never be approved at large user facilities.

   
   Nuclei will be studied by means of coincident ɣ-ɣ spectroscopy, in combination with charged particles spectroscopy and conversion-electron spectroscopy. Excited states of interest will be studied with a combination of light-ion induced reactions, specifically (ɑ,ɑ’ɣ), (ɑ,ɣ), (ɑ,pɣ), (p,ɣ), (p,p’ɣ), and also radioactive decay. Experiments will be performed in the Tandetron laboratory of the Institute of Physics, Slovak Academy of Sciences. The tandem accelerator delivers beams of protons up to 4 MeV and ɑ particles up to 6 MeV. Various types of target systems are available, including the gas target. The array of scintillation and germanium detectors is operational, together with corresponding electronics.

   Note: Školiteľ špecialista: Mgr. Andrej Herzáň, PhD.

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1. Ivančo, Ján: Trioxide tungsten films aimed at chemiresistive sensors of gaseous biomarkers of diseases

   (Vrstvy trioxidu volfrámu pre chemi-odporové senzory plynných biomarkerov chorôb)
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   Supervisor: Ivančo, Ján, Ing., PhD.

   Contact: jan.ivancosavbask

   Goals:
   

   • Characterization of physico-chemical properties of WO3 films.
   • Preparation of sputtered WO3 films with variant content of crystallographic phases.
   • Characterization of sensing properties of WO3 films towards particular gases/vapours such as acetone and formaldehyde in dependence upon the crystallographic phase of WO3.
   • To devise and experimentally verify a model for the sensing mechanism.

   Annotation:
   

   Thin films based on metal oxides have been presently investigated also in terms of their usage as active elements for sensors of trace concentration of particular gases and vapours. The PhD study will be focused to WO3 layers applicable primarily for a sensor of acetone vapours allowing non-invasive monitoring of  blood glucose level of diabetes patient determined per acetone concentration in the diabetic`s exhaled breath.
   The work will be executed at Institute of Physics of Slovak Academy of Sciences. During the PhD study, the student is going to have an access to the autonomously equipped lab (Laboratory of multilayers and nanostructures) furnished with various advanced facilities for both the preparation of active structures (evaporation and sputtering of films, growth of nanoparticle films) and for an exploration of physico-chemical, optical, morphological and sensing (the response to particular gases) properties. See e.g. (DOI:) 10.2478/jee-2019-0053 and/or 10.1039/c9cp02064k.

    
2. Majková, Eva: Low-dimensional nanomaterials for applications in biomedicine

   (Nízkorozmerné nanomateriály pre aplikácie v biomedicíne)
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   Supervisor: Majková, Eva, RNDr., DrSc.

   Contact: eva.majkovasavbask

   Annotation:
   

   Goals: Research of low-dimensional nanomaterials based of transitive metal oxides for photothermal effect applications in biomedicine

   The work is focused on the preparation and studies of low-dimensional transition metal oxide nanomaterials (2D nanoflakes, nanoparticles, quantum dots) exhibiting a strong surface plasmon resonance in NIR range. Being functionalized, such materials could be promising candidates for treatment of cancer cells by applying the photothermal effect. The essence of this method is a local increase of the temerature around the plasmonic nanoobject (around 42 °C) when it is irradiated by a laser beam of suitable wavelength. The starting material will be MoOx nanoflakes and nanodots developed and studied at the Institute at present.

   The importnat part of the work is the research of plasmonic properties of transition metal nanoobjects depending on the preparation methods, structure, size and their application in pilot photothermal effect experiments on standard cells. The design and realization of an experimental setup for photothermal effect studies in a model environment is planned as well.

   The work will be performed at the Institute of Physics SAS at the Department of multilayers and nanostructures. The Institute has at disposal all necessary technologies, diagnostics for research and development of transition metal oxide LD nanomaterials and the preliminary studies of the photothermal effect.

   The work addresses a highly topical issue in the research field of nanomaterials for biomedical applications. The PhD. student will obtain universal skills and experience with the latest experimental methods for the preparation and investigation of nanomaterials and will be actively engaged in an intense collaboration within the framework of several projects.

   References:
   1. X. Liu et al, Laser heating of metallic nanoparticles for photothermal ablation applications, AIP Advances 7, 025308 (2017); DOI: 10.1063/1.4977554
   2. G. Song et al, Hydrophilic Molybdenum Oxide Nanomaterials with Controlled Morphology and Strong Plasmonic Absorption for Photothermal Ablation of Cancer Cells, ACS Appl. Mater. Interfaces 2014, 6, 3915−3922, DOI: 10.1021/am4050184

    
3. Majková, Eva: Low-dimensional nanomaterials for energy conversion and storage

   (Nízkorozmerné nanomateriály pre konverziu a uskladňovanie energie)
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   Supervisor: Majková, Eva, RNDr., DrSc.

   Contact: eva.majkovasavbask

   Annotation:
   

   Goals: Research and development of low-dimensional materials for applications in photovoltaic devices  and structures for batteries

   The low-dimensional (LD) nanomaterails such as nanoflakes, nanowires, nanoparticles, nanodots, quantum dots and/or hybride nanomaterials composed of them are  very attractive research area. The LD nanomaterials reveal novel and interesting properties and open new areas of their applications in various structures and devices. The work will be focused on the research of LD nanomaterials for application in the structures of perovskite-based solar cells and application in electrodes for the batteries based on Na+.

   Nanomaterials will be prepared mostly in the form of colloidal solution with a low-size despersion. To achieve the goals, new LD nanomaterials as well as those already developed at the Institute of Physics SAS will be applied. The properties of selected transition metal chalcogenides nanoflakes, nanoparticles of noble metals and transition metal oxides, nanodots and quanum dots will be studied A brand new field will be the research of hybride nanomaterials composed of several types of LD nanomaterials which are promising especially for electrodes of Na+ based batteries.

   The work willl be performed at the Institute of Physics SAS at the Department of multilayers and nanostructures. The Institute has at disposal all necessary technologies for research and development of LD nanomaterials and necessary diagnostics for their characterization and functionalization as well as in-operando studies of processes in photovoltaic structures and battery electrodes.

   The work addresses a highly topical issue in the research field of nanomaterials and materials for energy conversion and storage. The PhD. student will obtain universal skills and experience with the latest experimental methods for the preparation and investigation of nanomaterials and will be actively engaged in an intense foreign collaboration within the framework of several international projects.

   Further information:
   1. Wang, P. et al. Solvent-controlled growth of inorganic perovskite films in dry environment for efficient and stable solar cells. Nat. Commun. 9, 2225 (2018)
   2. Y. Chen et al. Large-area perovskite solar cells – a review of recent progress and issues 10.1016/B978-0-12-812915-9.00001-0
   3. Prasant Kumar Nayak et al., From Lithium-Ion to Sodium-Ion Batteries: Advantages, Challenges, and Surprises Angew. Chem. Int. Ed. 2017, 56, 2–21, DOI: 10.1002/anie.201703772

    

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