Interfacial Concentration Research Articles

Construction and Properties Evaluation of the Binary Flooding System Based on Lipid Peptide.

To enhance crude oil recovery under complex reservoir conditions and reduce the environmental impact of the oil displacement system, a biosurfactant lipid peptide (TH) was combined with four chemical surfactants. From these combinations, those capable of achieving an ultralow interfacial tension region (<10-2 mN/m) were selected. The selected surfactant mixtures were then combined with polyacrylamide (HPAM) to construct a surfactant-polymer binary oil displacement system. The results showed that TH/OAB(2:1), TH/OAB(3:1), and TH/EAO(3:1) could reduce IFT to the ultralow interfacial tension region. Compound surfactants are easier to form mixed micelles than single surfactants, and the EACN of TH/OAB(2:1) and TH/EAO(3:1) is consistent with EACNOil, which can achieve higher surface activity at lower concentrations. The three compound surfactants have a wide range of ultralow interfacial tension concentrations and excellent antidilution performance. TH/OAB(2:1) and TH/EAO(3:1) have better antiformation adsorption performance than TH/OAB(3:1), and the oil washing rate of TH/OAB(2:1) is up to 80.30%. TH and OAB have spatial complementarity, which can increase the molecular packing density at the oil-water interface and reduce the IFT. In CaCl2 and NaCl solutions, the IFT of the two binary flooding systems constructed by TH/OAB(2:1) and TH/EAO(3:1) and HPAM remained in the ultralow interfacial tension region, with excellent salt resistance. When aged in the reservoir for 90 days, the IFT slightly increased but the viscosity decreased significantly. Adding a viscosity retaining agent (JW) was required to maintain the viscosity of the system. In the simulated oil displacement experiment, the recovery improvement of the two binary oil displacement systems was higher than those of surfactant and polymer alone. This study provides a new idea for the alkali-free surfactant-polymer binary oil flooding system and provides theoretical support for the practical application of TH in tertiary oil recovery.

Compressive behaviors and deformation mechanism of carbon fiber reinforced epoxy composites: A microscopic and molecular dynamics perspective

AbstractInvestigating the macro‐mechanical properties of polymer composites at the nanoscale is a challenging topic. Here we report the compressive performances of carbon fiber‐reinforced epoxy composites using molecular dynamics (MD) simulations. The evolution of microstructure and microscopic energy, including free volume, radius of gyration, dihedral angle, potential energy, and interaction energy, has been investigated to characterize compressive behaviors at the nanoscale. Molecular chains gradually bend, and the movement space of the molecular chains decreases during compression loading. The radius of gyration and dihedral angle are deformed into a state of irreversible plasticity to accommodate the microstructural transformation. The interaction energy increases and subsequently declines as the carbon fiber/epoxy interface gets closer, reflecting the transition of the internal structure. The inhomogeneity and interfacial concentration distribution of stress, and local molecular stiffness under various strains have been obtained to reveal the nanoscopic mechanism of epoxy failure and interface delamination during compression. This study reveals the compression behaviors and deformation mechanism of carbon fiber‐reinforced epoxy composites at the molecular level, providing directions and possibilities for molecular design and structural optimization of composites.Highlights The nanoscopic compression deformation of CFRP composites is studied. Microstructural evolution and conformation transformation are revealed. The evolution and transition of microscopic energy are analyzed. Micro‐mechanism of epoxy deformation and interface delamination is elucidated.

Mechanistic Insights into the Potentiodynamic Electrosynthesis of PEDOT Thin Films at a Polarizable Liquid|Liquid Interface.

Conducting polymer (CP) thin films find widespread use, for example in bioelectronic, energy harvesting and storage, and drug delivery technology. Electrosynthesis at a polarizable liquid|liquid interface using an aqueous oxidant and organic soluble monomer provides a route to free-standing and scalable CP thin films, such as poly(3,4-ethylenedioxythiophene) (PEDOT), in a single step at ambient conditions. Here, using the potentiodynamic technique of cyclic voltammetry, interfacial electrosynthesis involving ion exchange, electron transfer, and proton adsorption charge transfer processes is shown to be mechanistically distinct from CP electropolymerization at a solid electrode|electrolyte interface. During interfacial electrosynthesis, the applied interfacial Galvani potential difference controls the interfacial concentration of the oxidant, but not the CP redox state. Nevertheless, typical CP electropolymerization electrochemical behaviors, such as steady charge accumulation with each successive cycle and the appearance of a nucleation loop, were observed. By combining (spectro)electrochemical measurements and theoretical models, this work identifies the underlying mechanistic origin of each feature on the cyclic voltammograms (CVs) due to charge accumulated from Faradaic and capacitive processes as the PEDOT thin film grows. To prevent overoxidation during interfacial electrosynthesis with a powerful cerium aqueous oxidant, scan rates in excess 25 mV·s-1 were optimal. The experimental methodology and theoretical models outlined in this article provide a broadly generic framework to understand evolving CVs during interfacial electrosynthesis using any suitable oxidant/monomer combination.

A Versatile Metal-Organic-Framework Pillared Interlayer Design for High-Capacity and Long-Life Lithium-Sulfur Batteries.

Developing high-performance lithium-sulfur batteries is a promising way to attain higher energy density at lower cost beyond the state-of-the-art lithium-ion battery technology. However, the major issues blocking their practical application are the sluggish kinetics and parasitic shuttling reactions for sulfur and polysulfides. Here, pillaring multilayer graphene with the metal-organic framework (MOF) demonstrates the substantial impact of a versatile interlayer design in tackling those issues. Unlike regular composite separators reported so far, the participation of tri-metallic Ni-Co-Mn MOF (NCM-MOF) as pillars supports the construction of an ion-channel interconnected interlayer structure, unexpectedly balancing the interfacial concentration polarization, spatially confining the soluble polysulfides and vastly affording lithiophilic sites for highly efficient polysulfide sieving/conversion. As a demonstration, we show that the MOF-pillared interlayer structure enables outstanding capacity (1634 mAh g-1 at 0.1C) and longevity (average capacity decay of 0.034% per cycle in 2000 cycles) of lithium-sulfur batteries. Besides, the multilayer separator can be readily integrated into the high-nickel cathode (LiNi0.91Mn0.03Co0.06O2)-based lithium-ion batteries, which efficiently suppresses the undesired phase evolution upon cycling. These findings suggest the potential of "gap-filling" materials in fabricating multi-functional separators, bring forward the pillared interlayer structure for energy-storage applications.

A Versatile Metal‐Organic‐Framework Pillared Interlayer Design for High‐Capacity and Long‐Life Lithium‐Sulfur Batteries

Developing high‐performance lithium‐sulfur batteries is a promising way to attain higher energy density at lower cost beyond the state‐of‐the‐art lithium‐ion battery technology. However, the major issues blocking their practical application are the sluggish kinetics and parasitic shuttling reactions for sulfur and polysulfides. Here, pillaring multilayer graphene with the metal‐organic framework (MOF) demonstrates the substantial impact of a versatile interlayer design in tackling those issues. Unlike regular composite separators reported so far, the participation of tri‐metallic Ni‐Co‐Mn MOF (NCM‐MOF) as pillars supports the construction of an ion‐channel interconnected interlayer structure, unexpectedly balancing the interfacial concentration polarization, spatially confining the soluble polysulfides and vastly affording lithiophilic sites for highly efficient polysulfide sieving/conversion. As a demonstration, we show that the MOF‐pillared interlayer structure enables outstanding capacity (1634 mAh g‐1 at 0.1C) and longevity (average capacity decay of 0.034% per cycle in 2000 cycles) of lithium‐sulfur batteries. Besides, the multilayer separator can be readily integrated into the high‐nickel cathode (LiNi0.91Mn0.03Co0.06O2)‐based lithium‐ion batteries, which efficiently suppresses the undesired phase evolution upon cycling. These findings suggest the potential of “gap‐filling” materials in fabricating multi‐functional separators, bring forward the pillared interlayer structure for energy‐storage applications.

Time-Resolved Infrared Spectroscopic Evidence for Interfacial pH-Dependent Kinetics of Formate Evolution on Cu Electrodes.

By deployment of rapid-scan (second time scale) electrochemical FT-IR reflection-absorption spectroscopy, we studied the reduction of CO2 in 0.1 M Na2SO4 in deuterated water at a pD of 3.7. We report on the impact of dynamic changes in the bicarbonate equilibrium concentration in the vicinity of a polycrystalline Cu electrode, induced by step changes in applied electrode potential. We correlate these changes in interfacial composition and concentrations of dissolved species to the formation rate of formate, and provide evidence for the following conclusions: (i) the kinetics for the conversion of dissolved CO2 to formate (formic acid) are fast, (ii) bicarbonate is also converted to formate, but with less favorable kinetics, and (iii) carbonate does not yield any formate. These results reveal that formate formation requires (mildly) acidic conditions at the interface for CO2 to undergo a proton-coupled conversion step, and we postulate that bicarbonate reduction to formate is driven by catalytic hydrogenation via in situ formed H2. Interestingly CO was not observed, suggesting that the kinetics of the CO2 to CO reaction are significantly less favorable than formate formation under the experimental conditions (pH and applied potential). We also analyzed the feasibility of pulsed electrolysis to enhance the (average) rate of formation of formate. While a short positive potential pulse enhances the CO2 concentration, this also leads to the formation of basic copper carbonates, resulting in electrode deactivation. These observations demonstrate the potential of rapid-scan EC-IRRAS to elucidate the mechanisms and kinetics of electrochemical reactions, offering valuable insights for optimizing catalyst and electrolyte performance and advancing CO2 reduction technologies.

Effect of oil structure on adsorption behavior of emulsifier at the oil-polyol interface and the emulsion features

The aim of this study was to investigate the effect of oil structure on the dynamic adsorption behavior of emulsifier at the oil-polyol interface and the corresponding emulsion feature. Glycerol was used as the representative polyol, and the emulsifier was Polyglyceryl-2 Dipolyhydroxystearate (PGPH). Three kinds of alkanes and three kinds of ester oils were chosen for investigation. Firstly, the properties of each oil were studied by measuring surface tension (σ), interfacial tension with glycerol (γ0), and affinity between oils and PGPH. The results indicated that there was little difference in the fundamental characteristics of oils, with the exception of GTCC. Due to its triglyceride structure, GTCC exhibited similar polarity to glycerol, resulting in low interfacial tension and a strong affinity with PGPH. Secondly, the interfacial critical micelle concentration (CMCIFT), saturation adsorption amount (Γ∞), Langmuir constant (κ) and minimum molecular area (Amin) of PGPH were obtained by measuring the dynamic interfacial tension of PGPH adsorption at different oil-glycerol interfaces. The experimental results indicate that for alkanes, the longer the alkane chain length and the more the number of branch chains, the higher the emulsifier Γ∞ at the interface, leading to improved emulsion stability. In ester oils, the greater the affinity between the oil and glycerol, resulting in the lower the initial interfacial tension, a smaller Γ∞ and consequently smaller emulsion particle size. However, this also led to poor emulsion stability. Finally, Pearson correlation analysis was conducted between oil properties, adsorption parameters and emulsion size and stability. The results indicated that for alkanes, there was a negative correlation between particle size and emulsion stability with surface tension and Γ∞. In ester oils, there was a strong positive correlation between particle size and interfacial tension as well as κ. Additionally, the creaming of emulsions showed a strong negative correlation with interfacial tension and Γ∞.

Regulation interfacial energy by reducing the Young’s modulus of perovskite film in carbon-based HTM free MAPbI3 perovskite solar cell

In ambient air, a long-chain dodecafluorosuberic acid (DFSA) with lower Young’s modulus was introduced to improve the mechanical compatibility of perovskite/carbon interface. Firstly, the carbonyl groups CO and F– in DFSA can passivate the intrinsic defects of perovskite, the DFSA effectively reduces the Young’s modulus of the perovskite and mitigates residual stress generated during perovskite annealing procedure. Most importantly, DFSA significantly enhances the Young’s modulus compatible degree between DFSA-CH3NH3PbI3 (DFSA-MAPbI3, 35.8 GPa) and carbon (6.3 GPa), alleviating the interfacial stress concentration. Based on quantitatively analysis, interfical crack driving energy (Gd) is reduced from 0.63 to 0.43 J m−2, while the adhesive fracture energy (Ga) is increased from 0.47 to 0.54 J m−2, which reduces the probability of crack propagation and ductile delamination, and is conducive to the extraction and transmission of photogenerated carrior. This was also verified in finite element simulations. Finally, the photoelectric conversion efficiency (PCE) of the organic-inorganic hybrid perovskite (MAPbI3) PSC device is improved from 10.27 % to optimal 14.12 %. After service at room temperature with relative humidity (RH) of 50–55 % and high temperature of 85 °C for 720 h, the original efficiency is maintained at 72 % and 89 %, respectively.

Model-free chemomechanical interfaces: History-dependent damage under transient mass diffusion

This paper presents a data-driven framework based on distance functional for chemo-mechanical cohesive interfaces to capture transient diffusion and resulting interfacial damage evolution. The framework eliminates reliance on complex constitutive models and phenomenological assumptions, especially avoiding the coupling tangent terms with a given material database. The interfacial chemical potential and its jumps are used to expand the phase space for describing the chemical states of interfaces. Subsequently, a novel chemo-mechanical distance norm, including traction-separation pair, interfacial chemical potential-concentration pair and corresponding chemical potential jump-flux pair, is presented. Momentum conservation law for interfacial tractions and mass conservation law for interfacial concentration are enforced via Lagrange multipliers. For tracking the history-dependent state of the interface damage, an internal variable, termed interface integrity, is introduced to condition the interfacial database and manage the subsets mapping strategies, following physically motivated evolution constraints. Numerical examples are conducted to investigate the efficiency and capability of the present framework. A monotonic loading test validates a good numerical convergence relative to the number of data points. Subsequent cyclic loading simulations, compared with the reference solutions, show that the algorithm is well suitable to predict the history-dependent interface damage evolution under complex loading paths. Finally, the chemo-mechanically coupled examples capture phenomena such as interfacial swelling and interface degradation induced by transient diffusion and stress-driven diffusion. The current work provides a promising tool for understanding chemo-mechanical behaviors of interfaces within heterogeneous composites.

Two-stage work-hardening of a transformable B2-enhanced metallic glass composite by molecular dynamics simulation

The crystalline-amorphous interfaces play vital roles in affecting martensitic transformation, shear band nucleation and interface stability. Though both quasi-static and dynamic mechanical behaviors of shape memory enhanced bulk metallic glass composites have been studied via experiments, the atomic-level interactions among martensitic transformation, localized shear softening and interfacial strain concentration imposed by strain rate remain elusive. We employ molecular dynamics simulations to study strain rate effect on uniaxial compression behavior of transformable B2–CuZr enhanced bulk metallic glass composite. As strain rate increases, the proportion of martensitic transformation accelerates. During the competition among martensitic transformation induced-hardening, shear induced-softening and interface debonding, a two-stage work-hardening is observed, which is in agreement with experimental findings.

Structure of yuba films at the air/liquid interface as effected by the interfacial adsorption behavior of protein aggregates

The effects of adsorption behavior and assembly mechanism of proteins and lipids at the interface on the formation of yuba films were investigated. The thickness of yuba films increased rapidly from nano to micro scale within minutes according to the scanning electron microscopy (SEM) images. The confocal laser scanning microscope (CLSM), SEM images, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that the formation of protein aggregates (40–100 nm) was an essential requirement for the development of yuba. Meanwhile, a relatively loose spatial structure was formed by protein aggregates under the influence of water vapor. This structure served as the foundation for incorporating lipids. Interfacial adsorption kinetics indicated that increasing the concentration (from 3 to 9 mg/mL) of protein aggregates enhanced the rearrangement rate. This finding demonstrated that the variations of interfacial protein aggregate concentration were a crucial factor leading to the non-linear growth of film thickness.

Structures of Liquid-Liquid Interfaces in Partially Miscible Systems Revealed by Soft X-ray Imaging.

The properties of liquid-liquid interfaces are intricately linked to its structure, with a particular focus on the concentration distribution within the interface. To obtain precise information regarding the concentration distribution, we have developed a high-resolution soft X-ray imaging method for liquid-liquid interfaces. This work focused on representative partially miscible systems, analyzing the interfacial concentration distribution profiles of water-alkanols under both steady-state and dynamic processes, and obtaining the diffusion coefficients of different water concentrations in alkanols. Significant disparities in concentration distributions and the concentration-related diffusion coefficients were observed despite comparable diffusion distances within the same system across different states. Meanwhile, it was found that alkanols exhibit adsorption phenomena at the interface. This newfound knowledge serves as a crucial stepping stone toward a deeper understanding of partially miscible systems. Our study opens a way to explore liquid-liquid interface information with high-resolution.

Electrodeposition of CoSx-graphene nanoplatelets on Ni(OH)2 nanosheets for improving the pseudocapacitance performance

In the present work, binder-free CoSx–graphene nanoplatelets porous structures were coated on Ni(OH)2 nanosheets using a one-step electrodeposition process. The graphene was produced from the electroreduction of CO2∗ intermediates during the electrodeposition of CoSx. The surface morphology and interfacial bonding states of CoSx–graphene@Ni(OH)2 were sensitive to the deposition time and Co–to–thiourea molar ratio (Mr). The interface reconstruction between CoSx–graphene NCs and Ni(OH)2 nanosheets improved the pseudocapacitance performance, which was investigated at different Mr and varying deposition times. Raman spectra verified the presence of graphene and CoSx mixed phases in all heterostructure electrodes, where CoS2 was dominant at Mr = 0.2. An XPS analysis indicated the evolution of various interfacial bonding states (CO, CO, CoONi, and SO) between Ni(OH)2 nanosheets and CoSx-graphene nanoplatelets, revealing the improvement in the interfacial synergy and concentration of electroactive sites. The hybrid CoSx-graphene@Ni(OH)2 NCs at Mr = 0.2 exhibited the highest capacitance of 2116 F∙g−1 at 2 mV∙s−1 and 1618 F∙g−1 at 1 A∙g−1 compared with bare Ni(OH)2, which achieved 1212 F∙g−1 at 2 mV∙s−1 and 882.88 F∙g−1 at 1 A∙g−1, and other NCs. Bare Ni(OH)2 nanosheets retained only capacitance retention of 25 % after 2000 cycles, which improved to 70 % in all CoSx-graphene@Ni(OH)2 nanoplatelets.

High hardness and its strong layer-thickness dependence induced by martensitic transforming constituent in NiTi/Nb nanolayered thin films

Bulk composites made of transforming matrix and nanoinclusions possess exeptional mechanical properties owing to excellent interfacical strain matching as implemented by uniform lattice shear of martensitic constituents. Such an effect remains however largely unexploited in thin films. In this study, NiTi/Nb multilayered thin films with various individual layer thickness (h) were prepared by magnetron sputtering. Strong h-dependence in indentation hardness (23 GPa/nm−1/2) is discovered in NiTi/Nb multilayers, as compared to those (4–18 GPa/nm−1/2) in conventional bimetallic X/Nb multilayers where X = Cu, Ti, Ag, Al etc. Indentation hardness of NiTi/Nb multilayers saturates at 12 GPa, as compared to 2.6–8.5 GPa of X/Nb multilayers. In situ grazing incidence synchrotron X-ray diffraction reveals that the lattice strain of Nb in NiTi/Nb is 60–240 % greater than that in X/Nb. We suggest that such discrepancies may arise from the interfacial strain concentration relief facilitated by the transforming NiTi layers.

Review of the Interfacial Structure and Properties of Surfactants in Petroleum Production and Geological Storage Systems from a Molecular Scale Perspective.

Surfactants play a crucial role in tertiary oil recovery by reducing the interfacial tension between immiscible phases, altering surface wettability, and improving foam film stability. Oil reservoirs have high temperatures and high pressures, making it difficult and hazardous to conduct lab experiments. In this context, molecular dynamics (MD) simulation is a valuable tool for complementing experiments. It can effectively study the microscopic behaviors (such as diffusion, adsorption, and aggregation) of the surfactant molecules in the pore fluids and predict the thermodynamics and kinetics of these systems with a high degree of accuracy. MD simulation also overcomes the limitations of traditional experiments, which often lack the necessary temporal-spatial resolution. Comparing simulated results with experimental data can provide a comprehensive explanation from a microscopic standpoint. This article reviews the state-of-the-art MD simulations of surfactant adsorption and resulting interfacial properties at gas/oil-water interfaces. Initially, the article discusses interfacial properties and methods for evaluating surfactant-formed monolayers, considering variations in interfacial concentration, molecular structure of the surfactants, and synergistic effect of surfactant mixtures. Then, it covers methods for characterizing microstructure at various interfaces and the evolution process of the monolayers' packing state as a function of interfacial concentration and the surfactants' molecular structure. Next, it examines the interactions between surfactants and the aqueous phase, focusing on headgroup solvation and counterion condensation. Finally, it analyzes the influence of hydrophobic phase molecular composition on interactions between surfactants and the hydrophobic phase. This review deepened our understanding of the micro-level mechanisms of oil displacement by surfactants and is beneficial for screening and designing surfactants for oil field applications.

Advanced Nanocarbons Toward two-Electron Oxygen Electrode Reactions for H2O2 Production and Integrated Energy Conversion.

Hydrogen peroxide (H2O2) plays a pivotal role in advancing sustainable technologies due to its eco-friendly oxidizing capability. The electrochemical two-electron (2e-) oxygen reduction reaction and water oxidation reaction present an environmentally green method for H2O2 production. Over the past three years, significant progress is made in the field of carbon-based metal-free electrochemical catalysts (C-MFECs) for low-cost and efficient production of H2O2 (H2O2EP). This article offers a focused and comprehensive review of designing C-MFECs for H2O2EP, exploring the construction of dual-doping configurations, heteroatom-defect coupling sites, and strategic dopant positioning to enhance H2O2EP efficiency; innovative structural tuning that improves interfacial reactant concentration and promote the timely release of H2O2; modulation of electrolyte and electrode interfaces to support the 2e- pathways; and the application of C-MFECs in reactors and integrated energy systems. Finally, the current challenges and future directions in this burgeoning field are discussed.

Microstructure of monolayered aggregate of 5-(4-carboxyphenyl)-10,15,20-triphenylporphine self-assembled at the toluene/water interface

Abstract 5-(4-Carboxyphenyl)-10,15,20-triphenylporphine (TPPCOOH) was acid-dissociated and its salt with alkali metal ions (TPPCOO−M+, M+=Li+, Na+, and K+) formed ordered needlelike monolayered aggregates at the toluene/water interface under alkaline conditions. The light absorption of the aggregates at 451 nm depended on the polarization direction. The dependence revealed 2 types of TPPCOO−M+ aggregates with different growth direction, but their microstructure and interfacial concentration were almost the same. The height of the aggregates measured by atomic force microscopy was approximately equivalent to that of titled TPPCOO−.

Interfacial Biomacromolecular Engineering Toward Stable Ah-Level Aqueous Zinc Batteries.

Interfacial instability within aqueous zinc batteries (AZBs) spurs technical obstacles including parasitic side reactions and dendrite failure to reach the practical application standards. Here, an interfacial engineering is showcased by employing a bio- derived zincophilic macromolecule as the electrolyte additive (0.037 wt%), which features a long-chain configuration with laterally distributed hydroxyl and sulfate anion groups, and has the propensity to remodel the electric double layer of Zn anodes. Tailored Zn2+-rich compact layer is the result of their adaptive adsorption that effectively homogenizes the interfacial concentration field, while enabling a hybrid nucleation and growth mode characterized as nuclei-rich and space-confined dense plating. Further resonated with curbed corrosion and by-products, a dendrite-free deposition morphology is achieved. Consequently, the macromolecule-modified zinc anode delivers over 1250 times of reversible plating/stripping at a practical area capacity of 5 mAh cm-2, as well as a high zinc utilization rate of 85%. The Zn//NH4V4O10 pouch cell with the maximum capacity of 1.02 Ah can be steadily operated at 71.4mA g-1 (0.25 C) with 98.7% capacity retained after 50 cycles, which demonstrates the scale-up capability and highlights a "low input and high return" interfacial strategy toward practical AZBs.

Experimental and Theoretical Investigation of Zr‐Doped CuO/Si Solar Cell

Copper oxide (CuO) is a nanostructured semiconductor material with the potential for solar energy conversion and can be suitable for solar cells when used as a thin film. Herein, nondoped and doped (doping ratios of 1%, 2%, and 3% zirconium [Zr]) CuO thin films on silicon (Si) with the spin‐coating technique are developed. Optical and topological characterizations of CuO thin films are examined by ultraviolet‐visible and X‐ray diffraction. The electrical properties of nondoped and Zr‐doped CuO/Si heterojunctions are investigated with experimental current–voltage measurements in the dark and under illuminated conditions. The electrical behavior of nondoped and Zr‐doped CuO/Si heterojunctions is obtained using the experimental J–V technique and computational Cheung–Cheung and Norde methods. A simulation based on nondoped and Zr‐doped CuO/n‐Si heterojunction solar cells using SCAPS‐1D is completed. Photovoltaic (PV) parameters of experimentally produced and theoretically calculated CuO and Zr‐doped CuO/Si heterojunction solar cells are compared. Accordingly, PV parameters of 1% Zr‐doped CuO/Si solar cells show the highest power conversion efficiency calculated as a function of interfacial defect density and hole carrier concentration.

Surfactant Partitioning Dynamics in Freshly Generated Aerosol Droplets.

Aerosol droplets are unique microcompartments with relevance to areas as diverse as materials and chemical synthesis, atmospheric chemistry, and cloud formation. Observations of highly accelerated and unusual chemistry taking place in such droplets have challenged our understanding of chemical kinetics in these microscopic systems. Due to their large surface-area-to-volume ratios, interfacial processes can play a dominant role in governing chemical reactivity and other processes in droplets. Quantitative knowledge about droplet surface properties is required to explain reaction mechanisms and product yields. However, our understanding of the compositions and properties of these dynamic, microscopic interfaces is poor compared to our understanding of bulk processes. Here, we measure the dynamic surface tensions of 14-25 μm radius (11-65 pL) droplets containing a strong surfactant (either sodium dodecyl sulfate or octyl-β-D-thioglucopyranoside) using a stroboscopic imaging approach, enabling observation of the dynamics of surfactant partitioning to the droplet-air interface on time scales of 10s to 100s of microseconds after droplet generation. The experimental results are interpreted with a state-of-the-art kinetic model accounting for the unique high surface-area-to-volume ratio inherent to aerosol droplets, providing insights into both the surfactant diffusion and adsorption kinetics as well as the time-dependence of the interfacial surfactant concentration. This study demonstrates that microscopic droplet interfaces can take up to many milliseconds to reach equilibrium. Such time scales should be considered when attempting to explain observations of accelerated chemistry in microcompartments.