Graded-Gap Coatings for Organic Solar Cells

Crystal varizonicity: fundamental and applied aspects.

“…The most important result of this scheme was that the electronic band gap on the surface turned out to be smaller than the volume band gap by the value associated with the Modelung energy: E gb > E gs [2]. In a series of our works, by generalizing the results in [3][4][5], we obtained an analytical expression of the dependence of the band gap in an ion crystal on X, where X is the distance from the crystal surface to the observation point inside the crystal:…”

“…Moreover, they hypothesized about the shape of these potential wells and in the works [9][10], these potential pits were presented as Airy pits. We find these considerations interesting because in the cycle of our previous work [3][4][5], when studying the varizonicity of crystals with an ionic bond, we obtained some potential wells near the interface in the form of Airy. Because of this, we think it is interesting to combine the ideas of Airy pits and Airy electronic levels, expressed in this comment («Figure .4»), which play a basic role in the increase of Т с in the superconductivity of sandwiches for the case (LK-99).…”

“…After Tamm's work in 1932, where using the methods of quantum theory, he discovered local states on the surface (Tamm's levels), very significant results were obtained in the field of studies of the electronic structure of near-surface regions [2]. Recently, in a series of works [3][4][5] it has been shown that the exit of the variable zone to the surface leads to a completely new situation radically different from all previous works. «Figure 2» demonstrates how varizonicity creates potential pits of a special type (namely Airy pits) in which a whole group of local near-surface states can be localized.…”

“…The variant studied in this paper has not been considered before, and it is not due to the usually accepted flat zone structure, but to their varizonal type. It is essential that a special potential well (of the Airy type) appears on the surface, and this radically modifies the surface electronic structure, turning the Tamm's levels into something completely different [5] («Figure 4»). As our calculations show (in the same ε(k, ω) -formalism), this replacement actually modifies all components required for the calculation of Т с .…”