prof. Ing. Tomáš Polcar, Ph.D.

Transition Metal Dichalcogenides (TMDs) are denoted as MX2 where M is the transition metal and X is the chalcogen atom (S, Se or Te). The bulk TMDs are similar to graphite in the sense that they are composed of layers (just like graphene) that are held together with Van der Waals forces. 2D-TMDs can be metal, half metal or insulator depending on M. Moreover, they can be found in 1T, 2H or 3R geometry giving even more versatility in their properties. Furthermore, it is possible to combine single layers of different TMDs. Motivated by this versatility and combination options, we aim to investigate the physical, electronic and optical properties of TMD heterostructures using density functional theory (DFT) and time-dependent density functional theory (TDDFT) and exploit the new emerging properties for various applications.

Magnetron sputtering is an excellent tool to fabricate advanced thin films reducing friction and wear. Transition metal dichalcogenides represent a popular choice for solid lubricants; however, they fail in realistic environments such as higher temperature and or presence of humidity. We will use recent theoretical simulations to design nanostructure thin films combining solid lubricant phase with additional elements or compounds. Structural properties will be evaluated by various microscopy and spectroscopy techniques, mechanical properties will be measured by nanoindentation. The main objective is to describe the friction and wear mechanism and formulate a guideline for the nanoscale design of solid lubricant films.

High-entropy alloys (HEAs) constitute a distinctive class of materials with unique mechanical and physical properties, rendering them appealing for diverse industries, including automotive, aerospace, gas turbine blades, machine tools, high-temperature refractories, and hard tribological coatings. The project's objective is to employ atomistic simulations to comprehensively understand the intricate processes governing plasticity during nanoindentations and nanoscratch. Atomistic modeling entails simulating the material at the atomic or molecular level, facilitating a detailed examination of its structural and mechanical properties. Molecular dynamics simulations will be utilized to investigate the functional properties of selected materials, aiming to comprehend the influence of temperature and pre-existing extended defects on their radiation resistance, thermal stability, and tribological properties.

Carbon-based materials are often applied as thin coatings to reduce friction and wear. We can find them in many applications, such as the automotive industry or wearable electronics. Thanks to the variability of carbon structures and the ability to dope them with elements or compounds, we have almost unlimited material design options that fit our requirements. This project aims to develop a new class of low-friction carbon-based films optimized as low-friction protective coatings for sliding with polymers in dry or aqueous environments. You will design, deposit, and test diamond-like carbon coating sliding properties at a macroscopic scale and use advanced surface-sensitive techniques to identify the wear mechanisms. In particular, we will focus on the role of various dopants in forming effective tribolayer.

Nuclear energy, renowned for its cleanliness, cost-effectiveness, and reliability, ranks as the world's third-largest energy source, following thermal power and hydropower. Structural materials employed in nuclear power plants must exhibit comprehensive properties, encompassing excellent high-temperature characteristics, resistance to irradiation, and corrosion. High-entropy alloys (HEAs) or multi-principal-element alloys, characterized by unprecedented physical, chemical, and mechanical properties, have recently emerged as potential materials for advanced reactors. Their promising behavior in resisting irradiation makes them particularly noteworthy. This project introduces a novel refractory single-phase body-centered cubic (BCC) structured HEA, focusing on investigating the impact of ion irradiation on refractory high entropy alloys (HEAs). The research aims to uncover the effects of ion irradiation on this new HEA, emphasizing key parameters influencing radiation tolerance. These parameters include grain size, local chemical ordering, diffusion, alloy ratio, and composition. The ultimate objective is to pinpoint optimal conditions that enhance the radiation resistance of these alloys.