Superior Interface Properties Research Articles

Interface-enhanced germanium selenide solar cells comprising an ultrathin and uniform antimony selenide buffer layer via hydrothermal approach

Germanium selenide (GeSe) is a promising thin film photovoltaic absorber material owing to its excellent optoelectronic properties, high stability, and low toxicity. Interface engineering by introducing an ultrathin antimony selenide (Sb2Se3) buffer layer between the CdS electron transport layer and GeSe absorber layer is an effective technique for enhancing solar cell performance. However, the key to this technique is the fabrication of a uniform and smooth Sb2Se3 buffer layer with minimal thickness. In this study, instead of the conventional closed-space sublimation method, a hydrothermal method was employed to slowly grow an Sb2Se3 buffer layer with a thickness of approximately 8 nm. The Se/Na2SO3 molar ratio in the selenium source during the hydrothermal synthesis was adjusted; a molar ratio of 1:2 led to an uneven Sb2Se3 buffer layer thickness, whereas a molar ratio of 1:10 resulted in the formation of Sb2O3 particles on the buffer layer surface. When the Se/Na2SO3 molar ratio was 1:6, a smooth, uniform, dense, and impurity-free Sb2Se3 buffer layer was obtained, achieving the highest efficiency of 3.33 % in a GeSe solar cell. Moreover, GeSe solar cells with hydrothermally grown Sb2Se3 buffer layers demonstrated superior device interface properties and efficiency comparable with those using Sb2Se3 buffer layers deposited via closed-space sublimation. This technique offers an effective method for steadily improving the performance of GeSe solar cells.

Emulsification and interfacial characteristics of different surfactants enhances heavy oil recovery: experimental evaluation and molecular dynamics simulation study

The high viscosity and poor fluidity of heavy oil challenge its extraction, leading to the widespread use of surfactant emulsification to reduce viscosity and enhance recovery. This study evaluated three surfactants—sodium dodecyl sulfate (SDS), sodium oleate (SO), and APG0810—for their suitability and effectiveness in the X reservoir. The solution properties of these surfactants were analyzed and their micro-mechanisms investigated using MD calculations. The effects of surfactant concentration and additives on emulsification and viscosity reduction were elucidated. Ultimately, a system for emulsification and viscosity reduction was selected for physical simulation research. The experimental findings show that SO reduces interfacial tension from 52.4 mN/m to 0.0027 mN/m, transforming lipophilic surfaces into hydrophilic. MD analyses reveal SO’s optimal interfacial properties, with the lowest interfacial energy of −6423.4 kcal/mol, maximum interfacial thickness of 2.56 nm, and minimal diffusion coefficient of 0.4087 Å2/ps at the oil-water interface. These findings align with experimental results, confirming SO’s superior interfacial properties. Combining 0.3% SO with 0.5% n-pentanol results in a 98% viscosity reduction. The emulsion shows excellent stability, with no water separation in the first 30 min and only 8.3% after 2 h. Physical simulation results show that in high(low) permeability core displacement experiments, system flooding and subsequent water flooding can increase recovery rates by 15.39%(36.91%), indicating the system’s potential for enhancing oil recovery in Reservoir X. The findings suggest that the implementation of this system not only boosts the crude oil recovery rate but also carries economic significance in the industry.

Adsorption, Aggregation, and Application Properties of Green Pluronic Aliphatic Alcohol Ether Carboxylic Acids and Nonionic/Amphoteric Surfactants in Water.

In the realm of colloid and interface science, new types of green surfactants, including anionic Pluronic alcohol ether carboxylate (AEC), branched alkyl glucoside (IG), and zwitterionic coconut oil amide propyl betaine (CAB), have been identified and merit further exploration. AEC, characterized by its inclusion of 5 EO and 3.5 PO units, was synthesized, and its behavior in aqueous solutions with IG and CAB was meticulously examined. Their performance in applications such as foam generation, wetting, and the dispersion and stabilization of graphene was also evaluated. At αAE5P3C = 0.5, AE5P3C/CAB exhibited superior surface and interfacial properties compared to AE5P3C/IG. In these hybrid systems, the self-assembly of micelles is predominantly influenced by hydrogen bonding, electrostatic interactions, and hydrophobic forces. Kinetic analysis further confirmed that the driving force for micelle formation in these hybrid systems is enthalpy, with the adsorption process involving a mixed diffusion-kinetic adsorption mechanism. AE5P3C/CAB demonstrated enhanced foaming ability, foam stability, and wetting properties compared to AE5P3C/IG. Intriguingly, the optimal dispersion and stabilization of graphene were achieved with AE5P3C/IG at αAE5P3C = 0.2, providing a foundational basis for its potential application in graphene-based systems. A thorough examination of the synergistic mechanisms and application potential of these three distinct surfactants in aqueous solutions was presented, taking into account various charged ions and the specific hydrophilic and hydrophobic groups of EO and PO. This study not only provides fundamental insights into their intrinsic properties but also offers a fresh perspective for the ongoing exploration of green surfactants.

Mechanical and Electrical Conductivity Properties of Graphene/Cu Interfaces: A Theoretical Insight.

For graphene/copper (Gr/Cu) composites, achieving high-quality interfaces between Gr and Cu (strong interfacial bonding strength and excellent electron transport performance) is crucial for enabling their widespread applications in electronic devices. This study employs first-principles calculations and the nonequilibrium Green's function method to systematically investigate the mechanical and electrical conductivity properties of Cu(111)/Gr/Cu(111) interfaces with various stacking sequences and different forms of Gr. For these interface systems, the binding energy, separation work, charge transfer, and electrical conductivity across the interface were obtained. The results show that the top-fcc interface exhibits superior interfacial properties, characterized by relatively high binding energy (-3.00 eV/C atom) and separation work (≥0.78 J/m2), a small interfacial distance (2.85 Å), and enhanced electron transport capacity (2.12 G0/nm2). A bilayer form of Gr significantly reduces electronic conductance across the Gr/Cu interface by nearly 2.46 orders of magnitude. Furthermore, point defects in Gr, especially single-vacancy defects, disrupt the traditional trade-offs between mechanical and electrical performance, simultaneously enhancing mechanical performance by 7.50-124.36% and electrical performance by 33.02%. Additionally, stress mechanisms have been proposed to further enhance the interfacial electrical conductivity of Gr/Cu composites. The present study provides a theoretical basis for exploring the engineering applications of Gr/Cu composite materials.

Solvent-Activated Transformation of Polymer Configurations for Advancing the Interfacial Reliability of Perovskite Photovoltaics.

Organic materials have been widely used as the charge transport layers in perovskite solar cells due to their structural versatility and solution processability. However, their low surface energy usually causes unsatisfactory thin-film wettability in contact with the perovskite solution, which limits the interfacial performance of the photovoltaic devices. Although solvent post-treatment could occasionally regulate the wetting behavior of organic films, the mechanism of the solid-liquid interaction is still unclear. Here, we present evidence of a possible correlation between the solvent and the wettability of a conventional polymer, poly[bis(4-phenyl) (2,4,6-trimethylphenyl) amine] (PTAA), and reveal the critical roles of Hansen solubility parameters (HSPs) of solvents in wetting mechanisms. Our results suggest that the conventional solvent N,N-dimethylformamide (DMF) improves the wettability of PTAA by the morphological disruption mechanism but negatively impacts interfacial charge collection and stability. In contrast, 2-methoxyethanol (2-Me) with an appropriate HSP value induces the transformation of the PTAA configuration in an orderly manner, which simultaneously improves the wetting property and maintains the film topography. After careful optimization of the surface conformation of the PTAA film, both perovskite crystallization and interfacial compatibility have been enhanced. Benefiting from superior interfacial properties, the perovskite solar cells based on 2-Me deliver a champion efficiency of 24.15% compared to 21.4% for DMF-based ones. More encouragingly, the use of 2-Me minimizes the perovskite buried interfacial defects, enabling the unencapsulated devices to maintain about 95% of their initial efficiencies after light illumination for 1100 h. The present study demonstrates the high effectiveness of solvent-polymer interaction for adjusting interfacial properties and strengthening the robustness of perovskite solar cells.

An XPS Study of Electrolytes for Li-Ion Batteries in Full Cell LNMO vs Si/Graphite.

Two different types of electrolytes (co-solvent and multi-salt) are tested for use in high voltage LiNi0.5Mn1.5O4||Si/graphite full cells and compared against a carbonate-based standard LiPF6 containing electrolyte (baseline). Ex situ postmortem XPS analysis on both anodes and cathodes over the life span of the cells reveals a continuously growing SEI and CEI for the baseline electrolyte. The cells cycled in the co-solvent electrolyte exhibited a relatively thick and long-term stable CEI (on LNMO), while a slowly growing SEI was determined to form on the Si/graphite. The multi-salt electrolyte offers more inorganic-rich SEI/CEI while also forming the thinnest SEI/CEI observed in this study. Cross-talk is identified in the baseline electrolyte cell, where Si is detected on the cathode, and Mn is detected on the anode. Both the multi-salt and co-solvent electrolytes are observed to substantially reduce this cross-talk, where the co-solvent is found to be the most effective. In addition, Al corrosion is detected for the multi-salt electrolyte mainly at its end-of-life stage, where Al can be found on both the anode and cathode. Although the co-solvent electrolyte offers superior interface properties in terms of the limitation of cross-talk, the multi-salt electrolyte offers the best overall performance, suggesting that interface thickness plays a superior role compared to cross-talk. Together with their electrochemical cycling performance, the results suggest that multi-salt electrolyte provides a better long-term passivation of the electrodes for high-voltage cells.

Adjusting the pH of sizing agents to achieve superior interfacial and mechanical properties of carbon fiber reinforced epoxy composites

Interfacial properties were crucial in determining the mechanical properties of carbon fiber reinforced polymer composites (CFRPs). Applying appropriate sizing agents could effectively improve the interfacial properties of CFRPs. However, the influence of the pH of the sizing agents on the interfacial properties of CFRPs was still unclear. In this work, the above issues were elucidated by adjusting the pH of the diethanolamine-modified E51 (E51@DEA) sizing agent to investigate its impact on the interfacial properties of CFRPs. The molecular weight and emulsion particle diameter of E51@DEA increased with increasing pH of the sizing agent, despite the presence of identical chemical functional groups. E51@DEA-pH 7 showed the best interfacial enhancement. It exhibited ILSS and IFSS values of 102.24 and 113.45 MPa, respectively. This showed an increase of 76 % and 37 % when compared with T700. Additionally, the compressive and tensile strength of T700/E51@DEA-pH 7 also improved by approximately 13 % and 30 %, respectively. The suitable molecular chain length of the sizing agent and the high roughness of the surface of CFs were regarded as the contributing factors. This work further provided an effective and simple strategy for adjusting sizing agents to better improve the interfacial properties of CFRPs.

Multifunctional Zincophilic Hydrogel Electrolyte with Abundant Hydrogen Bonds for Zinc-Ion Capacitors and Supercapacitors.

The new-generation flexible Zn-ion capacitors (ZICs) require multifunctionality and environmental adaptability for practical applications. This essentially means that hydrogel electrolytes are expected to possess superior mechanical properties, temperature resistance, and tunable interface properties to resist flexibility loss and performance degradation over a wide operating temperatures range. Herein, a multifunctional polyzwitterionic hydrogel electrolyte (PAM/LA/PSBMA) with wide operating temperatures, excellent tensile ability, high water retention, and self-adhesion is designed. Molecular dynamics simulations and experimental results show that polar functional groups (-COO-, -SO3-, -C═O, and -NHCO-) in the hydrogel can form abundant hydrogen bonds with water molecules, which can destroy the original hydrogen bonds (HBs) network between the water molecules and have a low freezing point. It can also form coordination with Zn2+, so that the deposition of Zn2+ electric field homogenization effectively alleviates the growth of Zn dendrites. On this basis, the constructed Zn//Zn cell can be stably cycled 290 h at 10 mA cm-2 (1 mA h cm-2). The constructed ZICs and supercapacitor have a high specific capacitance, excellent energy density, good ionic conductivity, and long cycling stability. This study provides guidance on molecular design for the development of integrated multifunctional smart electronic devices that are environmentally adaptable, resistant to drying, and highly flexible.

Hierarchical interface design of jute fibers/polypropylene composites for enhanced interfacial and mechanical properties

Natural fiber reinforced plastics (NFRPs) represent a promising category of emerging materials for sustainable industrial development owing to their renewability, degradability, and lightweight. However, the polarity mismatch between the fibers and polymer matrices weakens the mechanical properties of NFRPs. To address this issue, a novel hierarchical interface design was proposed here through the co-modification of silane coupling agents (SCAs) and zinc oxide nanorods (ZnO NRs), which exhibits not only high efficiency but also low energy consumption and environmental friendliness. Specifically, the hierarchical interface design was demonstrated on jute fibers (JFs)/polypropylene (PP) composites, where the JFs/ZnO interfaces were chemically bonded through complexation, chelation, or coordination using various SCAs; meanwhile, the ZnO/PP interfaces were physically bonded by interlocking effect. The experimental testing results indicated the exceptional mechanical properties of modified JFs and their composites. The JFs modified with 3-glycidyloxypropyltrimethoxysilane (KH560) and ZnO NRs exhibited an increase of 34.3% and 55.8% in single-fiber tensile strength and tensile modulus, respectively, compared to sololy ZnO coated JFs, and also showed an augment of 30.8% in the interfacial shear strength with PP resin. Thus, the transverse and longitudinal tensile strength of JFs/PP composites with combined modification of KH560 and ZnO NRs were 19.2% and 46.5% higher than untreated ones. The interfacial enhancement mechanism was ascribed to the synergistic effect of chemical bonding and physical interlocking, as revealed by molecular dynamics simulation and observation of fracture morphologies. The findings offer a cost-effective solution for developing JFs/PP composites with superior interfacial and mechanical properties, thereby promoting the practical applications and value of NFRPs.

Investigation on microstructural evolution and local mechanical performance of friction stir lap welded AA6061-T6/ AA7075-T6 joints

The current study uses the friction stir lap welding (FSLW) technique to successfully fabricate two layered dissimilar AA6061/AA7075 joints. A defect-free joint with superior interfacial properties was obtained at the optimized process parameters (tool rotational speed / transverse speed) of 850 RPM/ 55 mm/min. The detailed investigations of microstructure evolution, crystallographic texture, and strength correlation were performed using the field emission scanning electron microscope (FE-SEM), optical microscope (OM), electron backscattered diffraction (EBSD), Vickers microhardness, nano-indentation, and miniature tensile tests. EBSD analysis reveals the presence of a significant grain refinement at the bottom (3.65 µm), middle (4.58 µm), and top region (6.34 µm) of stir zone (SZ) compared to AA6061 (42.56 µm) and AA7075 (34 µm) base metals. An increasing trend in the fraction of high angle grain boundary (FHAGBs) and recrystallization fraction was noticed from top to bottom of the build within the SZ. Continuous dynamic recrystallization (CDRX) with the gradient in strain, strain rate, and temperature leads to these microstructural variations within the SZ. The microhardness study shows a decrease in microhardness in the SZ due to thermal softening and precipitate dissolution at higher temperatures. Appreciable interfacial material mixing leads to remarkable strength, ductility, and strain-hardening behaviour within the SZ, especially at the interface section. Pole figures (PF) reveal the presence of major shear texture components (B/B̅, and C) with some minor presence of A1*/A2*and A/A̅ that confirms the presence of higher strains within the SZ. The dominant presence of recrystallization textures components (like cube {001} 〈110〉, Goss {011} 〈100〉, and P {011} 〈122〉 ) within the SZ confirms the presence of the CDRX mechanism.

Pretreatment with low-frequency magnetic fields can improve the functional properties of pea globulin amyloid-like fibrils

Plant protein fibrils have recently attracted considerable attention due to their superior mechanical and interfacial properties. The objective of this study was to evaluate the feasibility of low-frequency magnetic field (LF-MF) pretreatment in enhancing the conversion and functional characteristics of the amyloid-like fibrils derived from pea globulin (PG), which was considered a sustainable hypoallergenic protein. The results showed that LF-MF-treated PG (MPG) assembled into longer amyloid-like fibrils compared with native PG (NPG). The MPG presented similar gelling, emulsifying, and foaming properties to the NPG, while the fibril samples exhibited significantly improved functional properties. Moreover, the amyloid-like fibrils generated from the MPG (MPGF) showed large aspect ratios accompanied by superior solubility, molecular flexibility, emulsion stability, and gelling properties. The improved functional properties of the amyloid-like fibrils generated from the MPG can provide a promising outlook for expanding the applications of the PG in food, medicine and other fields.

Hybridization of cellulose nanocrystals modified ZnO nanoparticles with bio-based hyperbranched waterborne polyurethane sizing agent for superior UV resistance and interfacial properties of CF/PA6 composites

The interface of carbon fiber (CF) reinforced composites has been a long challenging issue that restricts the full utilization of its excellent properties in industrial applications. In present work, a green solvent γ-valerolactone and biogenetic derived gallic acid and tartaric acid were used to prepare a hyperbranched waterborne polyurethane (HWPU) sizing agent. Meanwhile, cellulose nanocrystal modified zinc oxide (CNC–ZnO) nanohybrids were successfully synthesized using a facile one-pot method to improve the dispersibility and specific surface area of ZnO nanoparticles. The hybridization of CNC–ZnO substantially enhanced the thermostability and UV resistance of bio-based HWPU. The mechanical properties of the modified composites were thoroughly examined, revealing remarkable enhancements in flexural strength and interlaminar shear strength, with improvements of 46.5 % and 48.1 % compared to pristine CF. Additionally, the interfacial shear strength test demonstrated a significant increase of 63.6 %. Remarkably, the modified carbon fiber composites retained more than 97 % of their mechanical properties after being subjected to continuous xenon irradiation for a week, highlighting the exceptional ultroviolet resistance derived from the hybrid HWPU sizing agent.

Electrochemically induced crystalline-to-amorphization transformation in sodium samarium silicate solid electrolyte for long-lasting sodium metal batteries

Exploiting solid electrolyte (SE) materials with high ionic conductivity, good interfacial compatibility, and conformal contact with electrodes is essential for solid-state sodium metal batteries (SSBs). Here we report a crystalline Na5SmSi4O12 SE which features high room-temperature ionic conductivity of 2.9 × 10−3 S cm−1 and a low activation energy of 0.15 eV. All-solid-state symmetric cell with Na5SmSi4O12 delivers excellent cycling life over 800 h at 0.15 mA h cm−2 and a high critical current density of 1.4 mA cm−2. Such excellent electrochemical performance is attributed to an electrochemically induced in-situ crystalline-to-amorphous (CTA) transformation propagating from the interface to the bulk during repeated deposition and stripping of sodium, which leads to faster ionic transport and superior interfacial properties. Impressively, the Na|Na5SmSi4O12|Na3V2(PO4)3 sodium metal batteries achieve a remarkable cycling performance over 4000 cycles (6 months) with no capacity loss. These results not only identify Na5SmSi4O12 as a promising SE but also emphasize the potential of the CTA transition as a promising mechanism towards long-lasting SSBs.

Enhanced Performance of GaAs Metal-Oxide-Semiconductor Capacitors Using a TaON/GeON Dual Interlayer.

In this work, a dual interfacial passivation layer (IPL) consisting of TaON/GeON is implemented in GaAs metal-oxide-semiconductor (MOS) capacitors with ZrTaON as a high-k layer to obtain superior interfacial and electrical properties. As compared to the samples with only GeON IPL or no IPL, the sample with the dual IPL of TaON/GeON exhibits the best performance: low interface-state density (1.31 × 1012 cm-2 eV-1), small gate leakage current density (1.62 × 10-5 A cm-2 at Vfb + 1 V) and large equivalent dielectric constant (18.0). These exceptional results can be attributed to the effective blocking action of the TaON/GeON dual IPL. It efficiently prevents the out-diffusion of Ga/As atoms and the in-diffusion of oxygen, thereby safeguarding the gate stack against degradation. Additionally, the insertion of the thin TaON layer successfully hinders the interdiffusion of Zr/Ge atoms, thus averting any reaction between Zr and Ge. Consequently, the occurrence of defects in the gate stack and at/near the GaAs surface is significantly reduced.

Influence of transition metal substitution on Cs2AgBiBr6/M3C2 (M = Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, and W) interfaces: First-principles and experimental studies

In this study, we have constructed and characterized Cs2AgBiBr6/M3C2 (M = Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, and W) heterostructures, utilizing a combination of density functional theory (DFT) and experimental studies. We constructed eighteen different Cs2AgBiBr6/M3C2 heterojunctions by considering the two different terminal types of Cs2AgBiBr6 as well as the nine different terminal types on the side of various early transition metal carbides. The results indicate that AgBiBr3/M3C2 heterostructures possess superior interfacial properties compared to Cs2BiBr3/M3C2 heterostructures, displaying a smaller interfacial distance, higher binding energy, and better charge transfer ability. Among the AgBiBr3/M3C2 heterostructures, AgBiBr3/Ti3C2 and AgBiBr3/Zr3C2 showed the best binding energy and charge transfer ability. Additionally, all the constructed heterostructures exhibited improved light absorption coefficient, broadened visible light absorption range, and reduced effective mass of the charge carriers. Finally, to validate the experimental synthesis feasibility of the theoretical models, we synthesized Cs2AgBiBr6/Ti3C2 composite materials, and scanning electron microscopy (SEM) images confirmed the presence of a composite structure consisting of Cs2AgBiBr6/Ti3C2. These results provide valuable theoretical guidance for developing high-performance Cs2AgBiBr6/M3C2 heterostructures in optoelectronic perovskite devices.

A novel bio-based hyperbranched waterborne polyurethane sizing agent with superior UV-resistance and interfacial properties for CF/PA6 composites

On account of environment concerns and the gradually depletion of fossil resources, a hyperbranched waterborne polyurethane (HWPU) serving for sizing agent of carbon fibers (CF) was designed based on bio-based materials. Hyperbranched chain extender named CAG was synthesized by citric acid (CA) and glycerol as HWPU precursor. Tartaric acid (TA) was coordinated with nano titanium dioxide (TiO2) through two –COOH groups, which was introduced to HWPU as the chain extender, leading to a significant improvement in ultraviolet (UV)-resistant of the sizing agent. The interfacial performance promotion of CF reinforced nylon 6 (CF/PA6) composites contributed by the HWPU sizing agent were systematically investigated. In contrast to the untreated CF composites, the mechanical performance arrived the best improvement after sizing by concentration of 1.5 wt%, which exhibited a dramatic promote of 44.9% in interlaminar shear strength (ILSS), 58.7% in interfacial shear strength (IFSS) and 43.3% in flexural strength. Extraordinary, the treated CF composites remained over 98% of mechanical performance after a week of unremitting ultraviolet irradiation, signifying the outstanding UV-resistance of the TiO2 modified HWPU sizing agent.

Polydopamine and polyethyleneimine comodified carbon fibers/epoxy composites with gradual and alternate rigid‐flexible structures: Design, characterizations, interfacial, and mechanical properties

AbstractPolymer composites with tailored structure and enhanced properties and functions have attracted great attentions due to their wide applications in materials science, nanotechnology, and engineering science. In this work, we demonstrate the innovative concepts of fabricating both gradual “rigid‐flexible” and alternate “rigid‐flexible” structures, which are achieved by altering the grafting sequence of flexible polyethyleneimine with high flexibility and polydopamine with suitable rigidity. Then, the effect of different rigid‐flexible structures on the structure and properties of the carbon fiber‐epoxy (CF/EP) composites are studied. It is found that the composites reinforced by the alternate rigid‐flexible polymer layer possess superior interfacial effects and mechanical properties. Compared with the CF/EP without polymer layer modification, the rigid‐flexible layer contributes to about 80.3% and 167.3% on the interfacial shear strength and the impact strength of final composites. These great improvements are attributed to the complex crack propagation path, more energy consumption, wider interface region, higher wettability, as well as strong physical and chemical interactions. This work provides practical and scalable potentials for regulating the structure and functions of the CF‐reinforced polymer composites by optimal interfacial design.

High-temperature-operating (over 140 °C) Li-ion supercapacitor via water-locking bimodal cross-linked hydrogel

The utilization of quasi-solid conducting medium possessing superior interfacial properties represents a significant approach in tackling the issue of leakage and stability in supercapacitors. However, preserving the conductivity of ions like Li+ and enabling their adaptability to high-temperature environments pose significant challenges to the improvement of water-locking capacity. Herein, a bimodal cross-linked hydrogel with a mesoporous structure has been developed based on the polyacrylamide-lithium chloride (PAM-LiCl) hydrogel system using polyethylene glycol (PEG). This hydrogel not only exhibits a high water-binding capacity but also facilitates the migration of Li-ions. Using activated carbon as the electrode material, the assembled quasi-solid state supercapacitor devices achieve a single electrode specific capacitance of 32.6 F/g at 0.1 A/g and an energy density of 1.77 W h/kg by varying the ratio of acrylamide and polyethylene glycol (AM/PEG). The findings of this study demonstrate that utilizing a bimodal cross-linked hydrogel can enable the operation of a supercapacitor at high temperatures above 140 °C.

Synergistic Fluorine⋅⋅⋅Sulfur Intra‐ and Intermolecular Interactions on Dopant‐Free Hole Transport Material for Efficient and Stable Inverted Perovskite Solar Cells

Designing dopant‐free small‐molecule hole transport materials (HTMs) with self‐assembly behavior via noncovalent interactions is considered as one effective strategy to achieve high‐performance inverted perovskite solar cells (PSCs). Herein, two donor‐π bridge‐donor (D–π–D) HTMs are presented, TPASF and TPAOF, containing 3,6‐dimethoxythieno[3,2‐b]thiophene as a core part with 3‐fluoro‐N,N‐bis(4‐(methylthio)phenyl)aniline and 3‐fluoro‐N,N‐bis(4‐methoxyphenyl)aniline as side group. The synergistic F⋅⋅⋅S dipole–dipole intra‐ and intermolecular interactions in TPASF drive the self‐assembly of this molecule into a supramolecular nanofibrillar network, leading to high hole mobility, superior interfacial properties, and providing a good growth template for the perovskite layer atop. The corresponding dopant‐free TPASF‐based inverted devices exhibit a promising power conversion efficiency of 21.01% with a long T 80 lifetime of ≈632 h under operational conditions. This work paves the way for the further development of new dopant‐free self‐assembled HTM designs for highly efficient and stable inverted PSCs.

Chitosan can improve the storage stability of ovalbumin fibrils at pH higher than isoelectric point

Food protein fibrils display superior mechanical and interfacial properties compared to the native protein. During processing, protein fibrils are stored for a long time and undergo pH shifts, which accelerate their degradation. In this study, the effects of chitosan on the morphology, structural and rheological properties of ovalbumin (OVA) fibrils after storage at pH higher than isoelectric point were studied. The results showed that OVA fibrils prepared at pH 2.0 remained stable after 7 days of storage. However, after storage at pH 8.0 for 7 days, the turbidity of OVA fibrils increased, the contour length and ThT fluorescence intensity decreased. Furthermore, OVA fibrils became stable again by interacting with chitosan via electrostatic interaction, which was confirmed by zeta potential. In addition, based on the results of Fourier transform infrared spectroscopy, sodium dodecyl sulfide polyacrylamide gel electrophoresis, and fluorescence spectra, it could be concluded that chitosan could interact with OVA fibrils at pH 8.0 during storage. Transmission electron microscope images indicated that the structure of OVA fibrils was maintained by the addition of positively charged chitosan. Finally, the viscosity and storage modulus of OVA fibrils after storage at pH 8.0 increased with the addition of chitosan. These findings implied that OVA fibrils were degraded when stored at pH above isoelectric point, but this degradation could be ameliorated by the addition of chitosan.