Membranes

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19 pages, 3602 KiB

Open AccessArticle

Sn and Ge Complexes with Redox-Active Ligands as Efficient Interfacial Membrane-like Buffer Layers for p-i-n Perovskite Solar Cells

by Azat F. Akbulatov, Anna Y. Akyeva, Pavel G. Shangin, Nikita A. Emelianov, Irina V. Krylova, Mariya O. Markova, Liliya D. Labutskaya, Alexander V. Mumyatov, Egor I. Tuzharov, Dmitry A. Bunin, Lyubov A. Frolova, Mikhail P. Egorov, Mikhail A. Syroeshkin and Pavel A. Troshin

Membranes 2023, 13(4), 439; https://doi.org/10.3390/membranes13040439 - 17 Apr 2023

Cited by 9 | Viewed by 2578

Abstract

Inverted perovskite solar cells with a p-i-n configuration have attracted considerable attention from the research community because of their simple design, insignificant hysteresis, improved operational stability, and low-temperature fabrication technology. However, this type of device is still lagging behind the classical n-i-p perovskite [...] Read more.

Inverted perovskite solar cells with a p-i-n configuration have attracted considerable attention from the research community because of their simple design, insignificant hysteresis, improved operational stability, and low-temperature fabrication technology. However, this type of device is still lagging behind the classical n-i-p perovskite solar cells in terms of its power conversion efficiency. The performance of p-i-n perovskite solar cells can be increased using appropriate charge transport and buffer interlayers inserted between the main electron transport layer and top metal electrode. In this study, we addressed this challenge by designing a series of tin and germanium coordination complexes with redox-active ligands as promising interlayers for perovskite solar cells. The obtained compounds were characterized by X-ray single-crystal diffraction and/or NMR spectroscopy, and their optical and electrochemical properties were thoroughly studied. The efficiency of perovskite solar cells was improved from a reference value of 16.4% to 18.0–18.6%, using optimized interlayers of the tin complexes with salicylimine (1) or 2,3-dihydroxynaphthalene (2) ligands, and the germanium complex with the 2,3-dihydroxyphenazine ligand (4). The IR s-SNOM mapping revealed that the best-performing interlayers form uniform and pinhole-free coatings atop the PC₆₁BM electron-transport layer, which improves the charge extraction to the top metal electrode. The obtained results feature the potential of using tin and germanium complexes as prospective materials for improving the performance of perovskite solar cells. Full article

(This article belongs to the Special Issue Ionic and Molecular Transport in Polymeric Electrolytes and Biological Systems Studied by NMR)

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15 pages, 1624 KiB

Open AccessArticle

Features of Self-Diffusion of Tridecane Molecules in a Porous Medium of Kaolinite Used as a Model of a Chemically Inert Membrane

by Aleksander Maklakov, Nariman Dvoyashkin and Elena Khozina

Membranes 2023, 13(2), 221; https://doi.org/10.3390/membranes13020221 - 10 Feb 2023

Viewed by 1274

Abstract

The present work focused on the experimental study of the specific features of self-diffusion of tridecane molecules in macroporous kaolinite, which is used as a raw material for the production of chemically inert membranes. The measurements of self-diffusion coefficients by pulsed magnetic field [...] Read more.

The present work focused on the experimental study of the specific features of self-diffusion of tridecane molecules in macroporous kaolinite, which is used as a raw material for the production of chemically inert membranes. The measurements of self-diffusion coefficients by pulsed magnetic field gradient nuclear magnetic resonance (PMFG NMR) revealed an increased translational mobility of tridecane molecules in kaolinite with incomplete filling of the pore space. This effect was accompanied by a sharp change in the slope of the Arrhenius plot of the self-diffusion coefficients of tridecane molecules in kaolinite. An analysis of the diffusion spin echo decay in the tridecane–kaolinite system revealed a discrepancy between the experimental data and the theoretical predictions, considering the effect of the geometry of porous space on molecular mobility. It was shown that the experimental results could be interpreted in terms of a model of two phases of tridecane molecules in the pores of kaolinite, in the gaseous and adsorbed state, coexisting under the fast-exchange conditions. Within the framework of the model, the activation energies of self-diffusion were calculated, which agreed satisfactorily with the experimental data. Additionally, the effects of the internal magnetic field gradients arising in a porous medium loaded with a gas or liquid on the data of the PFG NMR measurements were calculated. It was shown that the effect of magnetic field inhomogeneities on the measured self-diffusion coefficients of tridecane in kaolinite is small and could be neglected. Full article

(This article belongs to the Special Issue Ionic and Molecular Transport in Polymeric Electrolytes and Biological Systems Studied by NMR)

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12 pages, 1061 KiB

Open AccessArticle

Binding of Different Cyclosporin Variants to Micelles Evidenced by NMR and MD Simulations

by Polina P. Kobchikova, Sergey V. Efimov and Vladimir V. Klochkov

Membranes 2023, 13(2), 196; https://doi.org/10.3390/membranes13020196 - 5 Feb 2023

Cited by 1 | Viewed by 1636

Abstract

Peptides play a critical role in the life of organisms, performing completely different functions. The biological activity of some peptides, such as cyclosporins, can be determined by the degree of membrane permeability. Thus, it becomes important to study how the molecule interacts with [...] Read more.

Peptides play a critical role in the life of organisms, performing completely different functions. The biological activity of some peptides, such as cyclosporins, can be determined by the degree of membrane permeability. Thus, it becomes important to study how the molecule interacts with lipid bilayers. Cyclosporins C, E, H and L were characterised molecular dynamics simulation; NMR spectroscopy studies were also carried out for cyclosporins C and E. The comparison of one- and two-dimensional spectra revealed certain similarities between spatial structures of the studied cyclosporin variants. Upon dissolving in water containing DPC micelles, which serve as model membranes, subtle changes in the NMR spectra appear, but in a different way for different cyclosporins. In order to understand whether observed changes are related to any structural modifications, simulation of the interaction of the peptide with the phospholipid micelle was performed. The onset of the interaction was observed, when the peptide is trapped to the surface of the micelle. Simulations of this kind are also of interest in the light of the well-known membrane permeability of cyclosporin, which is important for its biological action. Full article

(This article belongs to the Special Issue Ionic and Molecular Transport in Polymeric Electrolytes and Biological Systems Studied by NMR)

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14 pages, 5796 KiB

Open AccessArticle

Effects of Natural Rhamnolipid Mixture on Dioleoylphosphatidylcholine Model Membrane Depending on Method of Preparation and Sterol Content

by Konstantin Potapov, Alexander Gordeev, Liliya Biktasheva, Maya Rudakova and Artem Alexandrov

Membranes 2023, 13(1), 112; https://doi.org/10.3390/membranes13010112 - 15 Jan 2023

Cited by 1 | Viewed by 1920

Abstract

Rhamnolipids as biosurfactants have a potentially wide range of applications, for example, as “green” surfactants or components of drug delivery systems, which is associated with the features of their interaction with cell membranes. However, as noted in the literature, those kind of features [...] Read more.

Rhamnolipids as biosurfactants have a potentially wide range of applications, for example, as “green” surfactants or components of drug delivery systems, which is associated with the features of their interaction with cell membranes. However, as noted in the literature, those kind of features have not been sufficiently studied now. This paper presents a study of the interaction of a natural mixture of rhamnolipids produced by bacteria of the rhizosphere zone of plants Pseudomonas aeruginosa with model membranes—liposomes based on dioleoylphosphatidylcholine (DOPC), depending on the method of their preparation and the content of sterols—ergosterol, cholesterol, lanosterol. Liposomes with rhamnolipids were prepared by two protocols: with film method from a mixture of DOPC and rhamnolipids; with film method from DOPC and injection of water solution of rhamnolipids. Joint analysis of the data of

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P NMR spectroscopy and ATR-FTIR spectroscopy showed that in the presence of rhamnolipids, the mobility of the head group of the DOPC phospholipid increases, the conformational disorder of the hydrophobic tail increases, and the degree of hydration of the C=O and P=O groups of the phospholipid decreases. It can be assumed that, when prepared from a mixture, rhamnolipids are incorporated into the membrane in the form of clusters and are located closer to the middle of the bilayer; while when prepared by injection, rhamnolipid molecules migrate into the membrane in the form of individual molecules and are located closer to the head part of phospholipids. The sterol composition of the model membrane also affects the interaction of rhamnolipids with the membrane. Here it is worth noting the possible presence of type of interaction between rhamnolipids and ergosterol differ from other investigated sterols, due to which rhamnolipid molecules are embedded in the area where ergosterol is located. Full article

(This article belongs to the Special Issue Ionic and Molecular Transport in Polymeric Electrolytes and Biological Systems Studied by NMR)

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Review

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39 pages, 11193 KiB

Open AccessReview

Polymer Electrolytes for Lithium-Ion Batteries Studied by NMR Techniques

by Vitaly I. Volkov, Olga V. Yarmolenko, Alexander V. Chernyak, Nikita A. Slesarenko, Irina A. Avilova, Guzaliya R. Baymuratova and Alena V. Yudina

Membranes 2022, 12(4), 416; https://doi.org/10.3390/membranes12040416 - 11 Apr 2022

Cited by 20 | Viewed by 5400

Abstract

This review is devoted to different types of novel polymer electrolytes for lithium power sources developed during the last decade. In the first part, the compositions and conductivity of various polymer electrolytes are considered. The second part contains NMR applications to the ion [...] Read more.

This review is devoted to different types of novel polymer electrolytes for lithium power sources developed during the last decade. In the first part, the compositions and conductivity of various polymer electrolytes are considered. The second part contains NMR applications to the ion transport mechanism. Polymer electrolytes prevail over liquid electrolytes because of their exploitation safety and wider working temperature ranges. The gel electrolytes are mainly attractive. The systems based on polyethylene oxide, poly(vinylidene fluoride-co-hexafluoropropylene), poly(ethylene glycol) diacrylate, etc., modified by nanoparticle (TiO₂, SiO₂, etc.) additives and ionic liquids are considered in detail. NMR techniques such as high-resolution NMR, solid-state NMR, magic angle spinning (MAS) NMR, NMR relaxation, and pulsed-field gradient NMR applications are discussed. ¹H, ⁷Li, and ¹⁹F NMR methods applied to polymer electrolytes are considered. Primary attention is given to the revelation of the ion transport mechanism. A nanochannel structure, compositions of ion complexes, and mobilities of cations and anions studied by NMR, quantum-chemical, and ionic conductivity methods are discussed. Full article

(This article belongs to the Special Issue Ionic and Molecular Transport in Polymeric Electrolytes and Biological Systems Studied by NMR)

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32 pages, 6909 KiB

Open AccessReview

Gradient NMR Method for Studies of Water Translational Diffusion in Plants

by Alexander Anisimov

Membranes 2021, 11(7), 487; https://doi.org/10.3390/membranes11070487 - 29 Jun 2021

Cited by 6 | Viewed by 3131

Abstract

The review of a retrospective nature shows the stages of development of the spin-echo NMR method with constant and pulsed gradient of the magnetic field (gradient NMR) for the study of water diffusion in plant roots. The history of the initial use of [...] Read more.

The review of a retrospective nature shows the stages of development of the spin-echo NMR method with constant and pulsed gradient of the magnetic field (gradient NMR) for the study of water diffusion in plant roots. The history of the initial use of gradient NMR for plants, in which it was not possible to experimentally confirm the bound state of water in cells, is described. The work presents the main ideas on which the technology of measuring diffusion by the spin-echo NMR method is built. Special attention is paid to the manifestations and record of the restricted diffusion phenomenon, permeability of membranes, along with the finite formulae used in real experiments. As examples, it gives the non-trivial results of studies of water transfer in roots through the symplastic system, from cell to cell through intercellular contacts with plasmodesmata, through aquaporins, transfer under the influence of changes in external pressure, and the composition of the gas atmosphere. Full article

(This article belongs to the Special Issue Ionic and Molecular Transport in Polymeric Electrolytes and Biological Systems Studied by NMR)

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64 pages, 13258 KiB

Open AccessReview

Molecular and Ionic Diffusion in Ion Exchange Membranes and Biological Systems (Cells and Proteins) Studied by NMR

by Vitaliy I. Volkov, Alexander V. Chernyak, Irina A. Avilova, Nikita A. Slesarenko, Daria L. Melnikova and Vladimir D. Skirda

Membranes 2021, 11(6), 385; https://doi.org/10.3390/membranes11060385 - 24 May 2021

Cited by 16 | Viewed by 4066

Abstract

The results of NMR, and especially pulsed field gradient NMR (PFG NMR) investigations, are summarized. Pulsed field gradient NMR technique makes it possible to investigate directly the partial self-diffusion processes in spatial scales from tenth micron to millimeters. Modern NMR spectrometer diffusive units [...] Read more.

The results of NMR, and especially pulsed field gradient NMR (PFG NMR) investigations, are summarized. Pulsed field gradient NMR technique makes it possible to investigate directly the partial self-diffusion processes in spatial scales from tenth micron to millimeters. Modern NMR spectrometer diffusive units enable to measure self-diffusion coefficients from 10⁻¹³ m²/s to 10⁻⁸ m²/s in different materials on ¹ H, ² H, ⁷ Li, ¹³ C, ¹⁹ F, ²³ Na, ³¹ P, ¹³³ Cs nuclei. PFG NMR became the method of choice for reveals of transport mechanism in polymeric electrolytes for lithium batteries and fuel cells. Second wide field of application this technique is the exchange processes and lateral diffusion in biological cells as well as molecular association of proteins. In this case a permeability, cell size, and associate lifetime could be estimated. The authors have presented the review of their research carried out in Karpov Institute of Physical Chemistry, Moscow, Russia; Institute of Problems of Chemical Physics RAS, Chernogolovka, Russia; Kazan Federal University, Kazan, Russia; Korea University, Seoul, South Korea; Yokohama National University, Yokohama, Japan. The results of water molecule and Li⁺, Na⁺, Cs⁺ cation self-diffusion in Nafion membranes and membranes based on sulfonated polystyrene, water (and water soluble) fullerene derivative permeability in RBC, casein molecule association have being discussed. Full article

(This article belongs to the Special Issue Ionic and Molecular Transport in Polymeric Electrolytes and Biological Systems Studied by NMR)

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20 pages, 2700 KiB

Open AccessReview

Ionic Mobility in Ion-Exchange Membranes

by Irina A. Stenina and Andrey B. Yaroslavtsev

Membranes 2021, 11(3), 198; https://doi.org/10.3390/membranes11030198 - 11 Mar 2021

Cited by 65 | Viewed by 7199

Abstract

Membrane technologies are widely demanded in a number of modern industries. Ion-exchange membranes are one of the most widespread and demanded types of membranes. Their main task is the selective transfer of certain ions and prevention of transfer of other ions or molecules, [...] Read more.

Membrane technologies are widely demanded in a number of modern industries. Ion-exchange membranes are one of the most widespread and demanded types of membranes. Their main task is the selective transfer of certain ions and prevention of transfer of other ions or molecules, and the most important characteristics are ionic conductivity and selectivity of transfer processes. Both parameters are determined by ionic and molecular mobility in membranes. To study this mobility, the main techniques used are nuclear magnetic resonance and impedance spectroscopy. In this comprehensive review, mechanisms of transfer processes in various ion-exchange membranes, including homogeneous, heterogeneous, and hybrid ones, are discussed. Correlations of structures of ion-exchange membranes and their hydration with ion transport mechanisms are also reviewed. The features of proton transfer, which plays a decisive role in the membrane used in fuel cells and electrolyzers, are highlighted. These devices largely determine development of hydrogen energy in the modern world. The features of ion transfer in heterogeneous and hybrid membranes with inorganic nanoparticles are also discussed. Full article

(This article belongs to the Special Issue Ionic and Molecular Transport in Polymeric Electrolytes and Biological Systems Studied by NMR)

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