Dimitri E. Khoshtariya (Staatliche Ivane-Javakhishvili-Universität Tbilissi, Georgien)
Rudi van Eldik (Friedrich-Alexander-Universität Erlangen, Deutschland)
Some New Horizons of 2D Nanoscience in Georgia and a Role of the
Alexander von Humboldt Foundation in respective
Georgian-German Collaboration
In contemporary 2D nanoscience, if two or several sub-nanometer-thick metallic, semi-metallic or semi-conducting layered structures dopable by the mobile charge carriers (electrons, holes) are sandwiched together with interstitial insulating film(s) of comparable thickness, under certain conditions such as the layers’ proper ‘hardness’ or ‘softness’, mutual angular alignment, the carrier’s suitable distribution, existence and strength of external perturbative factors (temperature, pressure, electric and magnetic fields, etc.), one may theoretically predict, or/and experimentally observe the charge carriers’ flow or counter-flow along or across the working sheets’ bodies. The formerly unthinkable prospects for both, fundamental and applied 2D nanoscience emerged thanks to the disclosure of outstanding sub-nanoscale physical properties of surfaces and interfaces due to the emergence of the novel unique combinations of specific quantum physical phenomena including the intra- and inter-layer spin-orbit coupling, the newly rethought − topologically determinable rehybridization of molecular orbitals (leading to uniquely delocalized electronic and vacancy states), emergence of uncommon molecular magnetic properties subjective to the inter-layer impact (via the quantum proximity effects) and external magnetic/electric factors. Furthermore, the charge carriers (electrons and holes), when placed in a close proximity, especially in the absence of a sizable environmental dielectric screening, normally form strongly bound dipoles which can be considered as dark remote excitons undergoing bosonic pairing (quasi-particle formation) by analogy with the prototypal case of a hydrogen atom. it is easy to see that the general structural (topological) prerequisites really match for two types (‘dry’ and ‘wet’) of counterpart layered 2D devices, and this fact strongly favors the logical prognosis that a whole range of the abovementioned collective physical (spin-implicated) empirical manifestations should be totally valid for the ‘wet’ analogs, as well. In this focused review, through the multi-theory based cross analysis of the selected current-voltage data collected over ca. two decades for two types of ‘wetted’ (liquid-phase-implicated) 2D layered (interfacially self-organized or self-assembled), densely packed nanodevices (under the conditions of very low dielectric screening by the environment), we will present the strong evidence that: (1) At reactants’ lower surficial concentrations (larger inter-reactant separations), at least the inter-layer single electron/single hole quantum BE-like pairing, as a precursor state to the inter-layer faradaic exchange process, should be taking place, strongly facilitating elimination of the activation free energy increment, and: (2) At reactants’ higher surficial concentrations and sufficient topological pre-arrangement conditions, as in the case of ‘dry’ spintronic counterpart layred devices, the itra- and inter-layer coherent multiparticle collective states (BE-condensates) may emerge providing the intra-layer charge-carrier flow and inter-layer charge-carrier exchange, seen also as the quasi-excitonic dipole flips. Furthermore, along the abovementioned generalization, we additionally substantiate the discovery of a new type of self-assembled, Au-deposited, atomically defined, factually bilayered hybrid (organic/inorganic), apparently topological 2D systems, represented by the archetypal 2D nanostructure such as: Au/L-cysteine/Cu(II/I), which are redox-functionalized inside the electrolyte assisted (‘wet’, however, easily solidifiable) electrochemical cells, exhibiting ability of coherent multi-electron/hole exchange, directly recognizable via the excellently resolved current-voltage (I–V) curves (paired cathodic/anodic volt-amperometric peaks). The robustness and tunable adaptivity of these systems along with a quality of experimental indicators warrant the highest valuebility for the further systematic fundamental and applied studies [1].