Formation of a Fast Charge Transfer Channel in Quasi-2D Perovskite Solar Cells through External Electric Field Modulation

Quasi-2D perovskites solar cells exhibit excellent environmental stability, but relatively low photovoltaic properties, compared with 3D perovskites solar cells. However, charge transport and extraction in quasi-2D perovskite solar cells are still limited by the inevitable quantum well effect, resulting in low power conversion efficiency (PCE). To date, most efforts concentrate on crystal orientation and favorable alignment during materials and films processing. In this paper, we demonstrated that the quasi-2D perovskite [(BA)2(MA)3Pb4I13 (n = 4)] solar cells show an optimized device performance through forming a fast charge transfer channel among 2D quantum wells through external electric field modulation, with appropriate modulation bias and time after the device has been fabricated. Essentially, ions will move directionally due to local polarization in quasi-2D perovskite solar cells under the action of electric field modulation. More importantly, the mobile ions function as a dopant to de-passivate the defects when releasing at grain boundaries, while decreasing built-in potential by applying forward modulation bias with proper modulation time. The capacitance-voltage characteristics indicate that electric field modulation can decrease the charge accumulation and improve the charge collection in quasi-2D perovskite solar cells. Photoluminescence (PL) studies confirm that the non-radiative recombination is reduced by electric field modulation, leading to enhanced charge transfer. Our work indicates that external electric field modulation is an effective method to form a fast charge transfer channel among 2D quantum wells, leading to enhanced charge transfer and charge collection through local polarization toward developing high–performance quasi-2D perovskite devices.

RUSSIAN CULTURAL SUBSTRATE IN THE ENGLISH TEXTS BY M. SHRAYER

Statement of the problem. At present when expansion of linguistic and cultural contacts between countries and peoples is growing, the problem of studying the phenomenon of transculturalism acquires particular relevance. Cultural interaction, fusion of cultural traditions and overcoming cultural isolation is reflected on the stage of linguistic interaction and translational creativity of emigrant writers who, being cut off from the linguistic processes of the metropolis in a new linguistic environment, use the language of the host country, combining elements of two linguistic systems and cultures. The purpose of this article is to study and single out the features of the Russian cultural substrate in the works by the modern emigrant writer M.D. Schrayer. Review of scientific literature on the problem. Along with a large number of works devoted to the language of translingual writers, works on the analysis of the Russian-language substrate in the texts by modern authors who create their texts in English are quite few and do not completely solve the problem of the functional significance of this phenomenon. The methodology (materials and methods). The article is based on the analysis and generalization of articles devoted to the problem of cultural substrate and translingual literature done by Russian and foreign linguists from the point of view of linguocultural analysis of the text, component analysis of the semantic structure of lexical units and synchronous comparison of linguistic units belonging to different systems. Research results. Based on the analysis of the texts by M. Schrayer functioning of the Russian-language substrate in the English texts was analysed. The methods of semantization of Russian cultural elements and their use in order to fulfill certain aesthetic functions were studied. It was revealed that the Russian cultural substrate is organically included in the description of Russian reality, creates the image of Russia, expands the idea of ​​the people inhabiting this country and their culture. Conclusion. The English-language literary texts by M. Schrayer are a vivid example of intercultural communication. The use of the Russian cultural substrate in English-language texts serves as a kind of information transfer channel at the intercultural level. Russian cultural elements demonstrate how an emigrant writer includes his experience in a literary work, they convey the author’s attitude, reveal the connection of his biography to an eventful series of his works, which ultimately forms and interprets the image of Russia in a foreign language communicative sphere.

Electronic structure and enhanced photoelectrocatalytic performance of RuxZn1−xO/Ti electrodes

Modification is one of the most important and effective methods to improve the photoelectrocatalytic (PEC) performance of ZnO. In this paper, the RuxZn1−xO/Ti electrodes were prepared by thermal decomposition method and the effect of Ru content on those electrodes’ electronic structure was analyzed through the first-principles calculation. Various tests were also performed to observe the microstructures and PEC performance. The results showed that as the Ru4+ transferred into ZnO lattice and replaced a number of Zn2+, the conduction band of ZnO moved downward and the valence band went upward. The number of photogenerated electron-hole pairs increased as the impurity levels appeared in the band gap. In addition, ZnO nanorods exhibited a smaller grain size and a rougher surface under the effect of Ru. Meanwhile, the RuO2 nanoparticles on the surface of ZnO nanorods acted as the electron-transfer channel, helping electrons transfer to the counter electrode and delaying the recombination of the electron-hole pairs. Specifically, the RuxZn1−xO/Ti electrodes with 9.375 mol% Ru exhibited the best PEC performance with a rhodamine B (RhB) removal rate of 97%, much higher than the combination of electrocatalysis (EC, 12%) and photocatalysis (PC, 50%), confirming the synergy of photoelectrocatalysis.