Two-dimensional (2D) materials represent crystalline materials consisting of only one layer of atoms. 2D materials are considered to be an emerging field of material science that is actively growing thanks to graphene in 2004 which is the first 2D material exfoliated from its bulk crystal. This discovery was significant for scientific community, which appreciated Andrey Geim and Konstantin Novoselov by the Nobel Prize in 2010. The isolation of graphene has provided an opportunity and stimulated to exfoliate a large family of 2D crystals with a wide range of electrical and optical properties suitable for construction of new optoelectronic devices. Much more 2D materials were exfoliated by state-of-art first-principles methods. There is no strict separation between 2D or not 2D but the general rule is to follow the quantum confinement effect which generally disappears when the thickness of the material exceeds a few atomic layers. 2D materials can be generally categorized according to their bulk counterpart as van-der-Waals or non vdW, elemental or compounds, etc.
Besides graphene, considerable attention has been paid to Transition Metal Dichalcogenides (TMDs) which are (in contrast to graphene) semiconductors of MX2 formula, where M is a transition metal atom (such as Mo or W) and X is a chalcogen atom (such as S, Se or Te). These materials provide a promising alternative to graphene because of a unique combination of properties: thickness-dependent bandgap, indirect-direct band gap transition, strong spin-orbit coupling make these materials to be favorable for optoelectronic applications allowing one to modify physical parameters like optical transitions, conductivity, electron mobility, electronic relaxation. TMDs are often combined with other 2D materials like graphene to make van der Waals heterostructures with tailorable properties. Depending on the aim, these heterostructures need to be optimized to get desired properties toward practical application as building blocks for many different devices such as field-effect transistors, photodetectors, solar cells, photocatalytic, and sensing devices.
In contrast to traditional 2D materials, metal-organic frameworks (MOFs) consist of inorganic centers and organic ligands being one of the research hotspots in material science over the past decades. Properties and structure of MOFs can be easily tuned by a proper selection of the metal centers and the ligands. Most of them can be prepared through wet chemical synthesis with low-cost and high yield. The structural characteristic of MOFs can be easily optimized by using different derivatives making remarkable advantages in hydrogen (H2) adsorption and evolution, CO2 storage and conversion, catalysis of oxygen (O2), rechargeable batteries, supercapacitors, and solar cells. Metal-organic frameworks that consist of cyclic organic molecules are of special interest because they allow one to obtain two-dimensional nanosheets. 2D covalent organic framework (COFs) and 2D MOFs can hold active centers with spin-orbit coupling and magnetism, which are important building blocks for realizing exotic materials such as topological, spintronic and quantum materials.
Our research is focused on theoretical investigation of fundamental properties in emerging nanomaterials and design of novel artificial 2D materials and heterostructures employing computer simulations and first principle methods. We develop approaches to enhance properties of 2D materials by interfacial engineering and chemical modifications. Depending on the task, we utilize various computational approaches that include simulations from several atoms to several thousands. Our current research objects are carbon nanomaterials, transition metal dichalcogenides, 2D magnets, quantum materials and other two-dimensional materials. We also provide prominent support to experimentalists in various area such as heterogeneous catalysis, photodetectors, and fundamental investigations of nanomaterials.
