Materials Engineering

Research Topic Summary.

The main aim of this study is to develop white organic light-emitting diodes (WOLEDs) with improved efficiencies and stability. The research focuses on developing new device structures using novel materials designed in the Department of Polymer Chemistry and Technology at the KTU. A primary goal is to establish a clear relationship between the emissive properties of these new materials and the output parameters of WOLEDs. The research plan encompasses the following main tasks: 1. Investigation of the photophysical, electrooptical, and charge-transporting properties of novel organic materials; 2. Development of innovative white-emitting systems as OLED emitters; 3. Exploration of new approaches to enhance the efficiencies of WOLEDS through fabrication, characterization, and optimization of electroluminescent devices.

Research Topic Summary.

Chromium oxide coatings, due to its unique properties, are widely used in technical, medical, energetic and electronic applications. However, the application of Cr2O3 coatings for tribological systems is limited by the insufficient adhesion to the substrate, poor fracture toughness, high friction coefficients and low wear resistance at high temperatures. The coatings of Cr2O3 composites (Cr2O3-ZrO2, Cr2O3-TiO2, etc.) deposited by the plasma spraying has higher wear resistance, lower friction coefficient and are more plastic. The use of various materials (SiC, TiC, TiO2, ZrO2, graphite etc.) additions to the Cr2O3 matrix provides formation of self-lubricant composite coatings. The adhesion strength of Crl2O3 composite coating increases with the formation of metallic interlayers. However the investigations related to the influence of origin and thickness of the inter-layer on various types of Cr2O3 composite (COC) coatings are insufficient. The researches of tribological properties of the COC coatings at non-lubricated conditions are fragmentary.

Research Topic Summary.

The research is focused on the development of sustainable multifunctional organic and organic–inorganic composites based on biopolymers, endowed with antimicrobial, antioxidant, therapeutic, protective, and other functionalities, as well as on the analysis of the interrelationships between their properties and behavior. The main approaches to achieve these objectives include theoretical and experimental studies, along with simulation and modeling of system behavior.

Research Topic Summary.

In recent years, autonomous driving, Internet of Things, and growing data storage needs have caused a surge in data generation. This has driven demand for new memory solutions that are fast, non-volatile, and energy-efficient. To boost processing speeds, it's crucial to minimize the read/write gap between fast RAM and slower storage due to von Neumann architecture limits. The project intends to investigate the formation and properties characterization of Hf0.5Zr0.5O2 (HZO) thin films doped with isovalent and heterovalent isosized ions (Sn, Tb, Ta, Bi, Sc, Co) deposited by reactive direct current magnetron sputtering deposition. The proposed idea is based on the fact that ions similar to Hf and Zr can significantly change the ferroelectric properties of HZO, which are currently not yet developed for the production of ferroelectric memories (FRAM) and would be competitive with existing memories. The project will study the influence of isovalent, acceptor and donor impurities and deposition temperature influence on HZO properties. Crystalline, surface morphology, elemental composition and ferroelectric properties are being studied. It is expected that the project research will significantly accelerate and will make cheaper FRAM technology. Our proposed way of substituting of Hf and Zr ions with their close relatives contribute understanding of mechanisms, appearing in phase structure changes, leading to creation of excellent ferroelectric. Another prediction is that we can obtain a morphotropic phase boundary in doped HZO, which can radically change ferroelectric properties of this material.

Research Topic Summary.

The European Union (including Lithuania) aims to reduce greenhouse gas emissions by 40% by 2030 and become climate-neutral by 2050, that is, an economy with net-zero greenhouse gas emissions. To meet the objective at the heart of the European Green Deal, renewable (emission-free) electricity must be coupled with photoelectrochemical technologies that convert naturally abundant H2O, CO2, and N2 molecules into synthetic fuels and chemical feedstocks. Photoelectrochemical water splitting utilizing solar energy and earth-abundant semiconductors is one of the most widely researched areas for hydrogen production. Recent advancement in photoelectrochemical technologies is optically active “plasmonic” metal nanoparticles that have emerged as a promising approach to facilitate light-driven chemical conversions under far milder conditions than thermal catalysis. This work aims to create heterostructures from self-assembled plasmonic nanostructures and semiconductor materials and characterize their photoelectrochemical properties and the efficiency of hydrogen generation. The objectives of the work are devoted to the development of nanoparticle self-assembly and transfer methods into controlled configuration heterostructure arrangements, preserving the initial spatial distribution and associated optical resonances. To select the synthesis conditions for nanoparticles formed by different methods, and to form nanoparticles and characterize their properties. To investigate the relation between the plasmonic and photocatalytic properties of nanoparticles and the photoelectrochemical efficiency of water splitting. Finally, to select the most efficient combination of semiconductor material and plasmonic nanoparticles for the photoelectrode.

Research Topic Summary.

Graphene is a 2D nanocarbon material, carbon atomic hexagons monolayer. It is at the top of the significant interest due to the giant electron and hole mobility, charge carrier multiplication, flexibility, optical transparency, chemical inertness and other outstanding properties. One of the possible applications of the graphene is use of the graphene in Schottky contacts instead of the metal. Due to the very high mobilities the graphene can be used as a channel layer in field effect transistors and transistor based biosensors. Till now graphene was usually synthesized by chemical vapor deposition of the graphene on catalytic Cu, Ni, Co foils. Afterward, the long process of the graphene transfer onto the targeted semiconductor or dielectric substrates was used. It is a complex and time consuming procedure. Control of the graphene/semiconductor contact and graphene nanolayer properties are complicated in such a case. In present study graphene will be directly synthesized on the semiconductor surface by plasma assisted processes on semiconducting and dielectric substrates. Effects of the graphene structure on characteristics of the field effect transistors (FETs) and photosensors will be studied. The relation between properties of the synthesized graphene layer and characteristics of the graphene-based sensors will be studied.

Research Topic Summary.

This project aims to develop ultra-sensitive SERS substrates for trace-level detection of pollutants exploiting self-assembled plasmonic nanoparticle arrays. During the research, plasmonic nanoparticles (Au, Ag) will be formed and analysed, evaluating their structure evolution dependence on synthesis conditions and optical properties. Employing theoretical calculations, the influence of plasmonic lattice and plasmonic nanoparticle multimer on the local field enhancement over typical Raman excitation wavelengths will be determined. The self-assembled nanoparticle SERS substrates will be tailored and verified for pollutants sensing.

Research Topic Summary.

Glass is a solid amorphous material widely used due to its optical transparency as well as its thermal and chemical resistance. Optical lenses, mirrors, touch screens, and devices of integrated optics are made of glass. During operation, glass surfaces often become dirty, and when in contact with a warm and humid environment, they tend to fog up. As a result, the optical transmittance of glass decreases and image distortions appear. To increase the operational efficiency and longevity of devices, antifogging, self-cleaning, and antireflective glass surfaces are created, the functionalization of which is performed by changing the surface morphology and chemical composition. Such surface modification can significantly improve the optical properties, but the final result greatly depends on the type and chemical composition of the functionalized glass. There is still a lack of systematic studies that analyze the influence of various factors. The purpose of this work is the functionalization and peculiarity analysis of various types of glass surfaces in order to reduce surface reflections and change the wettability of the glass, thus ensuring self-cleaning and antifogging behaviour of the surfaces, and accelerating the melting of the formed ice. The planned research will lead to the creation of advanced antifouling glass surfaces for optical applications.

Research Topic Summary.

Over the last years, a wide range of multiferroic materials and structures have been assessed for technological applications. Within these efforts, the challenge was the compatibility of these materials with silicon-based technologies. Most of the traditional perovskite ferroelectrics are incompatible with the complementary metal-oxide-semiconductor (CMOS) technology. In addition, ferroelectric properties of perovskites oxides often deteriorate with reduced film thickness that makes a composite structure impractical at the nanoscale. Recently, ferroelectricity has been discovered in wurtzite aluminum scandium nitride (AlScN) films, which may help to address the abovementioned challenges. The AlScN based ferroelectric thin films are also promising as a ferroelectric component in multiferroic heterostructures for the high-density memory applications, which is based on reducing of single elements cells up to nanoscale. Despite the abundance of many studies, there remain many unanswered technological and scientific questions related to the microstructure of these layers, degradation, reaction with substrate materials, etc. Worldwide research has shown that the ferroelectric and magnetoelectric properties of these layers depend on the synthesis method, conditions and dopands, which increase the distortion of the crystal lattice and, at the same time, the ferroelectric properties. The work will involve the synthesis of AlScN layers by reactive magnetron sputtering, adding transition metal impurities (Zr, Nb, Ni, Co) and the investigation of the dependence of the multiferroic properties of the layers on them.

Research Topic Summary.

The mechanism of bacterial adhesion to solid surfaces is a complex process affected by multiple factors. The most important property of the bacterial adhesion mechanism is influenced by the physicochemical interaction of the bacterial cells. The bacterial adhesion is determined by surface topography and roughness, free surface energy, including Van der Valse and electrostatic forces or acid-alkaline interactions, the potential arising in the phase boundary, hydrophobicity, and surface charge. Surface derivatives, much smaller than bacterial cells, have been found to inhibit binding, reducing the interaction between bacterial cells and solids. Using nanoparticles (metal and metal oxide) as antibacterial surfaces is a viable way. Most metallic or metal oxide nanoparticles (Ag, TiO2, CuO, ZnO, etc.) have bactericidal properties through the generation of reactive oxygen species. However, some of them are effective due to nanostructures and surface potential. Nano-particles formed on ceramic surfaces can disrupt the integrity of the bacterial cell membrane and its potential, activating the production of oxygen-free radicals that act as nanocatalysts. The project will investigate: a) the formation of thin ceramic films by physical vapor deposition methods, selecting optimal forming technologies; b) the influence of technological parameters on the catalytic and antibacterial properties of the thin films; and c) the physicochemical investigation of the formed thin films. The project aims to investigate the physical, chemical, and other characteristics of antimicrobial thin films and, based on the research, enable the practical use of such systems.

Research Topic Summary.

Specific imaging applications and related optical systems require diffractive optical elements capable of integrating multiple functions within a single component, thereby replacing traditional optics and simplifying system design and footprint. This research aims to develop ultrashort-pulse laser-based micro/nano-processing and self-assembly technologies for the fabrication of diffractive optical elements as an alternative to conventional lithography methods. The main objectives include modeling diffractive optical elements based on plasmonic and dielectric meta-atoms and adapting them for applications such as sensing and imaging. Furthermore, the study will investigate surface and volume micro/nano-structuring using state-of-the-art femtosecond laser treatment combined with selective wet etching and dry plasma etching to establish next-generation diffractive optics fabrication technologies. Self-assembly in deposition templates and particle transfer techniques will be employed to integrate nanostructures onto laser-fabricated surfaces, transforming them into functional photonic elements. The proposed PhD topic is aligned with the Marie Skłodowska-Curie Actions Doctoral Network project application currently under preparation.

Research Topic Summary.

This PhD project focuses on the optimization of lab-scale perovskite solar cell (PSC) fabrication, the integration of novel materials (alternatives to C60) for enhanced stability and efficiency, and advanced analysis of losses at the electron transport layer/perovskite interface. Conducted in a state-of-the-art laboratory, the work combines process development, materials testing, and feedback-driven characterization to drive innovation in PSC technology.

Research Topic Summary.

The field of photovoltaic devices has been developing particularly rapidly recently, as significant progress has been made in improving hole transport materials. Further progress and stability in perovskite solar cell (PSC) technology depends heavily on the search for new, effective organic hole-transporting materials as an alternative to the conventional Spiro-OMeTAD for non-doped layers. It is expected that new targeted materials will increase the stability of organic light-emitting diodes (OLEDs) and PSCs, which will open up opportunities for commercialization of these devices. The objective is to investigate the photophysical properties, charge transport (TOF and CELIV methods), and stability of organic semiconductors used as hole-transporting materials in new efficient organic light-emitting diodes and/or perovskite solar cells.

Research Topic Summary.

This research focuses on advancing organic light-emitting diodes (OLEDs) by developing novel, metal-free fluorescent emitters with extended emission lifetimes, aiming to overcome limitations in efficiency and material lifespan that currently constrain OLED technology. Leveraging organic semiconductors for their lightweight and flexible properties, the PhD candidate will synthesize new donor-acceptor compounds and examine their optoelectronic behavior using theoretical and experimental methods. These materials will be tested in OLEDs, oxygen sensors, and photodetectors, with findings published in leading scientific journals and presented at international conferences. Additionally, the PhD candidate will have opportunities for long-term internships at partner research institutions in Germany, Poland, France, Latvia, and the UK.

Research Topic Summary.

Organic semiconductors are actively used in organic optoelectronic devices such as organic light-emitting diodes (OLEDs), organic and perovskite photovoltaic cells, photodetectors, organic lasers, and various sensors. Organic semiconductors, which show both good charge-transporting properties and efficient short-lived emission, are particularly desirable for the development of fast OLEDs and efficient electrically driven short-pulse organic lasers. These devices are needed for wireless data transmission devices. The aim of the research is to design, synthesize, and investigate organic semiconductors characterized by efficient short-lived fluorescence and efficient charge transport. Glass-forming organic semiconductors with fluorescence quantum yield of at least 50% in solid state, an emission lifetimes of not linger that 5 ns, and charge carrier mobility of not less than 10?3 cm2 V?1 s?1 will be the target. The glass transition temperatures of the synthesized molecular glasses are expected to be not less than 100 °C.

Research Topic Summary.

In the current work, the research on the optical studies of colloidal solutions of silver nanoparticles, production of templates of regular two-dimensional nanostructures for capillarity-assisted particle assembly, as well as studies of surface lattice resonance (mixed mode of LSPR and light diffraction in a regular structure) is planned for lasing applications.

Research Topic Summary.

The use of industrial polymeric waste in the development of new functional materials is a promising area for the development of sustainable technologies. One way to give functional materials targeted properties is to chemically modify their surface and create structures with internal functional layers. Secondary raw materials are already mixtures that are hampered by contamination with residues of additives required for the properties of the former product. The aim of the research is to search for new possibilities of using industrial polymer waste (plastics, textiles) in the development of new functional materials.

Research Topic Summary.

The interaction of light with resonant structures enables optical measurements, which can be used to detect minuscule changes in the contacting medium related to contaminants or specific binding events on surfaces. Periodic photonic structures can be formed by employing self-assembly from colloidal solutions on dedicated surfaces with appropriately sized traps. This method is suitable for originating periodic structures from monodisperse nanoparticle coloids. Such 2D photonic structures, or metasurfaces, demonstrate high-quality resonances in the extinction spectrum related to the plasmonic lattices or otherwise surface lattice resonances. The position of the resonance is very sensitive to the surrounding/contacting medium, as it changes the effective refractive index in the structure and can operate as a transducer element in an optical sensor. This work aims to develop a specific binding detection platform based on self-assembled plasmonic nanoparticle array systems. The research will help to optimize the plasmonic nanoparticle densities and geometries within the array and its compatibility for refractometric sensing via visible spectroscopy. Then, the application of the nanoparticle chips for the detection of model and real-life pollutant samples will follow. The topic of the PhD is related to the Doctoral Networks - Marie Skłodowska-Curie Actions call project application that is currently being prepared.

Research Topic Summary.

With the recent intensive development and deployment of high-technologies such as microelectronics, optoelectronics, nanotechnology, or biotechnology, the need for flexible production of precise and small parts produced from sustainable polymers has been growing rapidly. Optical 3D printing technologies are perfect for this. In these technologies, replacing petroleum-derived materials with those derived from renewable materials, particularly suitable for the production of reprocessable, reusable and recyclable polymers, would provide ecological and economic benefits. The aim of this work is to develop new sustainable photopolymers from renewable raw materials that would be suitable for optical 3D printing. During the work, photosensitive resins of various plant-derived monomers will be developed, their composition and photopolymerization conditions will be optimized, the structure and properties, as well as reprocessability, reusability and recyclability of the obtained photopolymers will be investigated. Selected combinations of plant-derived materials will be tested in optical 3D printing devices and offered for commercialization. During doctoral studies, internships are planned in the laboratories of other European universities. The research results will be published in scientific journals indexed in the Web of Science database, presented at international conferences or patented, and presented to the general public.

Research Topic Summary.

Functional textile materials exhibit various properties such as antimicrobial, antistatic, liquid-repellent, and odor-absorbing effects. These features are introduced either during raw material modification or through finishing processes. Textiles are widely used in medical applications, including healthcare garments, surgical sutures, wound dressings, drug delivery systems, and tissue scaffolds. Materials intended for wound treatment must promote tissue regeneration and possess antibacterial properties. This research aims to develop sustainable and functional medical textiles using biodegradable polymers and environmentally friendly production technologies.

Research Topic Summary.

Micro/nanoplastic and Per- and polyfluoroalkylated compounds, the so-called “forever chemicals”, pollution in aquatic ecosystems, including drinking water, has become crucial for human and environmental health. The aim of this study is to develop cheap and reliable microfluidic devices for sensitive detection of pollutants in liquids using laser-structured porous membranes. The objective of the research is to evaluate porous paper membranes and effect on their laser micro processing in order to effectively control the flow of analytes. To develop nanomaterials suitable for colorimetric detection and visualization of specific binding with the pollutants. Finally, to develop a paper-based microfluidic device for pollutant detection in liquid analytes. It is expected to develop and characterize a colorimetric microfluidic sensor that can be applied to the detection of various pollutants in liquids. The topic of the PhD is related to the Doctoral Networks - Marie Skłodowska-Curie Actions call project application that is currently being prepared.

Research Topic Summary.

During the creation of jacquard fabrics, one of the most important problems is the appropriate selection of the composition and structure of the fabric pattern. The weavability and behavior of the fabric during weaving depends on the choice of these jacquard fabric indicators. Choosing the wrong pattern composition and/or weaves with very different warp crimps for a jacquard fabric can cause some groups of warp threads to overstretch and others to loosen. Therefore, the weavability of such a fabric can be bad. In some cases, jacquard fabrics with poorly selected composition and structural solutions may be completely impossible to weave. For the optimal jacquard fabric composition and structure, the warp thread crimp should be the same across the entire width of the fabric. The aim is to create a new methodology for choosing the composition and structural solution of jacquard fabrics and a prototype of jacquard fabric with optimal weaving properties and to test it under real conditions of use.

Research Topic Summary.

The objective of this project is to develop a corrosion-resistant measurement scale technology and prototype, designed for operation in aggressive environments. The relevance of this research is substantiated by the recently implemented technology at JSC “Precizika Metrology” (https://www.precizika.com/) where raster linear scales are fabricated on stainless-steel tapes using picosecond laser radiation. To date, no fundamental studies have been reported on the combined effects of laser structuring and low-temperature nitriding on the surface of structured steel. The influence of such a complex treatment on the microstructure, optical characteristics, and corrosion resistance of steel remains unknown. To advance understanding in this field, systematic experimental investigations will be conducted, focusing on plasma-assisted low-temperature nitriding. A novel RF inductively coupled plasma beam source (COPRA RF ICP ion source) will be employed to generate a stable plasma, in which nitrogen molecules (N2) are ionized and partially dissociated into active species. The study aims to establish stable nitrogen ion beams with optimized ion concentration and energy suitable for efficient nitriding of picosecond-laser-structured steel substrates. Appropriate process parameters - gas flow rate, working pressure, and RF power - will be optimized. Standard salt-spray corrosion tests will be performed to assess the impact of the combined laser structuring and nitriding treatments on the corrosion resistance of the modified steel surfaces. Comprehensive analyses of the surface structure, morphology, composition, and optical properties of the samples will enable the identification of correlations between the laser-induced ripples and nitriding parameters. The resulting insights will support the optimization of nitriding duration, temperature, and ion-beam characteristics, ultimately contributing to the development of a robust, corrosion-resistant measurement scale technology.