Mixed Dimethyl Sulfoxide Research Articles

A DMSO/MOE mixed solvent system for improving the morphology and efficiency of kesterite solar cell

A mixed dimethyl sulfoxide (DMSO) and 2-methoxy ethanol (MOE) solvent system was developed to prepare high-quality kesterite Cu2ZnSn(S, Se)4 (CZTSSe) film. The precursor films made pure DMSO system show a tube-like microstructure morphology, which can be changed by adding MOE to the solution. The increase of MOE in the precursor solution is a key in the crystalline characteristic of the absorber and connecting performance with thin film solar cells. As VMOE = VDMSO, the CZTSSe layer can achieve good contact with the back electrode and obtain large grains across layers. The addition of MOE solvent effectively improves the fill factor (FF). Specifically, both the fill factor and efficiency are increased from 49.67% and 6.43% to 64.83% and 10.99%, respectively, with the addition of 2 mL of MOE into precursor solution prepared by DMSO.

A modified perlite protocol with a mixed dimethyl sulfoxide and trehalose cryoprotectant improves the viability of frozen cultures of ectomycorrhizal basidiomycetes

ABSTRACTHomolka’s perlite protocol (HPP) was evaluated for cryopreservation of a wide range of ectomycorrhizal basidiomycete cultures, then a modified perlite protocol (MPP), in which cryoprotectant was added just before freezing rather than during the culturing process, was applied to cryosensitive strains that failed to survive when HPP was used. Further modifications of MPP with various cryoprotectants were explored to improve the cryopreservation of hard-to-preserve strains. The efficacy of HPP was assessed in 111 strains of 38 species of basidiomycetes of various cryosensitivities. After freezing strains using HPP, the viability and colony diameter of the strains were examined after 2 wk, 6 mo, and 1 y of storage at −80 C. Of the 111 strains tested, 91 survived after 1 y of storage with high viability of 80% or more, whereas the remaining 20 strains exhibited low and unstable viability. For those selected cryosensitive strains that did not survive well when HPP was used, MPP was applied with a mixture of cryoprotectants, dimethyl sulfoxide (DMSO), glycerol, and trehalose, at different concentrations and combinations. Toxicity testing of the cryoprotectants in the nonfrozen state revealed that 12% (v/v) glycerol was highly toxic for six strains (four species), whereas DMSO (5% and 10% [v/v]) was less toxic than glycerol. The viability of the cryosensitive strains after freezing demonstrated that DMSO was more efficient than glycerol, and trehalose enhanced the cryoprotective effects of both glycerol and DMSO when MPP was used for cryopreservation. Our comparative analysis of MPP with various combinations and concentrations of cryoprotectants revealed that a mixture of 5% DMSO and 10% trehalose was the most effective cryoprotectant, and that using MPP with this cryoprotectant was applicable to many cryosensitive strains.

Formation of Proton-Conducting Polymer Additives Based on Sulfonated Crosslinked Polystyrene in Nafion Membranes

A method for the in situ modification of Nafion perfluorinated proton-conducting membranes with a polyelectrolyte based on sulfonated crosslinked polystyrene has been developed. The method is based on the radical copolymerization of styrene with divinylbenzene in situ in the transport channels of Nafion and subsequent sulfonation. The use of a mixed dimethyl sulfoxide–isopropanol solvent, which provides, on one hand, an effective swelling of the Nafion membrane and, on the other hand, the diffusion of nonpolar monomers into the hydrophilic transport channels of the membrane, makes it possible to obtain samples with a uniform distribution of the polyelectrolyte throughout the membrane thickness. The developed method provides a significant increase in the charge carrier concentration and the proton conductivity of the membranes.

The Effect of Solvents on the Performance of CH3NH3PbI3 Perovskite Solar Cells

The properties of perovskite solar cells (PSCs) fabricated using various solvents was studied. The devices had an indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS)/CH3NH3PbI3 (fabricated by using various solvents)/fullerene (C60)/bathocuproine (BCP)/silver (Ag) structure. The solvents used were dimethylformamide (DMF), γ-butyrolactone (GBL), dimethyl sulfoxide (DMSO), a mixture of DMSO and DMF (1:1 v/v), and a mixture of DMSO and GBL (DMSO: GBL, 1:1 v/v), respectively. The power conversion efficiency (PCE) of the device fabricated using DMF is zero, which is attributed to the poor coverage of CH3NH3PbI3 film on the substrate. In addition, the PCE of the device made using GBL is only 1.74% due to the low solubility of PbI2 and CH3NH3I. In contrast, the PCE of the device fabricated using the solvents containing DMSO showed better performance. This is ascribed to the high solubilization properties and strong coordination of DMSO. As a result, a PCE of 9.77% was obtained using a mixed DMSO:GBL solvent due to the smooth surface, uniform film coverage on the substrate and the high crystallization of the perovskite structure. Finally, a mixed DMSO: DMF:GBL (5:2:3 v/v/v) solvent that combined the advantages of each solvent was used to fabricate a device, leading to a further improvement of the PCE of the resulting PSC to 10.84%.

A novel strategy for making poly(vinyl alcohol)/reduced graphite oxide nanocomposites by solvothermal reduction

Poly(vinyl alcohol) (PVA)/reduced graphite oxide (rGO) nanocomposites were synthesized by solvothermal reduction of graphite oxide (GO) in the presence of PVA. The solvent, the mixed dimethyl sulfoxide (DMSO)-dimethylformamide (DMF), could act not only as a reducing agent but also as a good stabilizer, which achieved effectively reduction of GO in the PVA matrix and avoided the agglomeration of rGO during reduction. A 53.0% increase in tensile strength and 52.6% improvement of Young’s modulus were achieved by addition of 3wt% of rGO. Furthermore, a significant improvement of thermal stability was observed for the PVA/rGO nanocomposites.

Hemin binding to serum proteins and the catalysis of interprotein transfer.

The reaction of hemin (Hm) with human hemopexin (Hx) has been studied in a mixed dimethyl sulfoxide (Me2SO)-water solvent system and in aqueous caffeine solutions. In both media, the kinetics could be described by a single, second-order process: (formula - see text) with k = 1.8 X 10(6) M-1 s-1 in 40% Me2SO-water [pH 7.4, mu = 0.2 M (NaCl)] and k = 3.9 X 10(7) M-1 s-1 in water [pH 7.4 mu = 0.2 M (NaCl), [caffeine] = 0.025 M]. The reaction shows an ionic strength dependence consistent with a residual 1+ to 2+ charge in the vicinity of the binding region of the protein. The kinetics of the transfer of hemin from albumin to hemopexin (formula - see text) were studied as a function of concentration, ionic strength, pH, and temperature. In experiments conducted at 3 less than or equal to [Alb]0/[Hx]0 less than or equal to 20 where the transfer kinetics are first order, k' = 5 X 10(-3) S-1 at mu = 0.3 M (NaCl), pH 7.1; the reaction is strongly dependent on ionic strength and choice of electrolyte. The addition of imidazole catalyzes this transfer process via a ligand-mediated pathway with k' = 5 X 10(-3) + 21[Im]T2. At [Alb]0/[Hx]0 = 92, the noncatalyzed transfer reaction is second order. From the kinetic analysis of the reaction under these conditions, an estimate is made of the distribution of hemin between the two proteins at concentration levels which are characteristic of serum. The association of hemin and hemopexin is approximately 30 times faster than that of hemin and albumin, a finding consistent with the recycling function of hemopexin during heme transport to the liver parenchymal cells.

Preferential Solvation of Single Ions: The PH4ASPH4B Assumption for Single Ion Thermodynamics in Mixed Dimethylsulfoxide‐Water Solvents

AbstractThe paper presents a study of the Ph4AsPh4B assumption as for verification of its plausibility for the determination of thermodynamic quantities of single ions in mixed dimethylsulfoxide (DMSO)‐water solvents. For discussion the solvation energy is considered as a composite of electrostatic and neutral components. The neutral components are replaced by experimental data of Ph4Ge and Ph4C which are proved to be equal, of their size and structure, to the reference cation and anion. The electrostatic components are obtained by calculation according to the theory in the literature. The results of the present investigation provide the conclusion that an assymmetric partition is preferred to an equal partition practiced in the literature. Based on the study, the standard free energies of transfer for single ions, Ph4As+, Ph4B, Cs+ and I−, are determined and for others, H+, Li+, Na+, K+, Rb+, Cl− and Br− evaluated from the data of salts known in the literature. Discussion is elaborated with solvation properties of individual ions.

The enhancement of the fluorescence of fluorescamine derivatives in mixed dimethylsulfoxide—water solvents

The enhancement of the fluorescence of fluorescamine derivatives in mixed dimethylsulfoxide—water solvents