Carrier Properties Research Articles

Controlling Chelation and Esterification in Pechini Synthesis for Enhancing Chemical Looping Steam Methane Reforming using LaFeO3 Perovskite.

The properties of an oxygen carrier, such as crystalline structure, textural properties, and surface chemical species, significantly influence the redox performance in thermochemical redox applications. This study presents the synthesis of various lanthanum orthoferrite (LaFeO3) perovskites by adjusting Pechini synthesis parameters, including chelating agent ratio, calcination temperature, and solution pH. A larger surface area emerged as a dominant factor contributing to improved redox performance. The porosity of the polyester resin proves crucial in achieving a large surface area and a small particle size for the oxygen carrier. This goal could be attained by controlling the pH of the precursor solution. A low degree of chelation or precipitation may lead to uneven cation distribution, resulting in the enrichment of trace hydroxide impurities. These impurities can suppress the reducibility of particles during the looping experiment. Various investigations, using XRD, XPS, XAS, SEM, and N2 physisorption, revealed that porosity and crystallinity can be controlled by altering the synthesis parameters.

Energy Band Alignment and Defect Synergistic Regulation Enable Air-Solution-Processed Kesterite Solar Cells With the Lowest VOC Deficit.

The major challenge in preparing high-performance Cu2ZnSn(S,Se)4 solar cells is the large open circuit voltage deficit (VOC-def). A new strategy utilizing the synergistic substitution of Ag and In dual cations has been proposed to simultaneously address the problems of undesirable interface band alignment and high-density detrimental bulk defects, obtaining decreased carrier recombination rate and increased minority carrier lifetime. The shorter In-S/Se bonds move the CBM higher by generating stronger repulsive force than the Sn-S/Se bonds, thus adjusting the interface band alignment. Ag substitution can effectively suppress Cu─Zn disorder, while Ag, In dual substitution can further passivate Sn-related defects and solve the issue of low carrier concentration in Ag single-substituted samples. Besides, the superior carrier property of In-Se materials significantly enhanced the device carrier lifetime and minority carrier diffusion length. The state-of-the-art air-solution-processed CZTSSe device without any addition treatment with 14.33% efficiency and 580mV VOC is obtained, possessing the lowest VOC-def value currently available in the CZTSSe field (VOC/VOC SQ = 64.7%). This work emphasizes the synergistic modulation of band alignment, defect level, grain growth, and carrier transportation by dual cation substitution, which paves a convenient and effective way to realize high-performance solar cells and photovoltaic devices.

Luminescence Patterns on Multimillimeter Single-Crystal MAPbBr3 Microplatelets via Thermal Ablation Effects.

The single crystal distinguishes itself as the most outstanding representative of excellent optoelectronic performance among perovskite semiconductors due to its exceptional charge carrier properties, extraordinary optophysics, precise structural geometries, and superior material stabilities. However, it exhibits mediocre performance in light emission, which can be attributed to its excessive carrier diffusion lengths and extremely low recombination rates. To address this challenge, this study puts forward a controllable high-temperature annealing treatment strategy concentrating on multimillimeter-scale MAPbBr3 micrometer-thick platelet single crystals (MPSCs). Through the utilization of thermal ablation effects to convert the surface monocrystalline lattices into polycrystalline perovskite nanocrystals (PNCs) with a remarkably increased specific surface area, the fluorescence intensity arising from the rapid recombination of free carriers on the PNC surface is enhanced by 320 times compared to the pristine MPSC surface. These PNCs produced through surface annealing, with the characteristic of loose adhesion to surfaces, can be mechanically wiped away and regenerated in situ via reannealing the residual MAPbBr3 MPSCs, guaranteeing high intensity, durability, and standard geometric fluorescence. Moreover, by regulating the surface distributions of thermal ablation effects and carrying out embossing annealing treatment or laser direct writing, we can design and fabricate relatively complex, high-contrast (255×), and clearly resolved fluorescence patterns on MPSC surfaces.

N-doped carbon dots/SnS2 heterostructures for ultra-fast and sub-ppb-level detection of NO2 in multiple environments

Nitrogen dioxide (NO2) is one of the most common toxic gases, which not only impairs human health but also produces secondary pollutants induced by sunlight via associated photochemical reactions. Herein, we design a high-performance NO2 sensor based on the N-doped carbon dots/SnS2 (N-CDs/SnS2) heterostructure using density functional theory (DFT) calculations. The DFT results approve that the decoration of N-doped carbon dots (N-CDs) onto the SnS2 nanosheet enhances adsorption capacity and electron transportation compared with those of pure SnS2, significantly enhancing the sensing responses. In addition, these in-situ synthesized N-CDs onto SnS2 nanosheet leads to band alignment, thereby significantly improves conductivity and enhances transportation and storage properties of carriers via a synergistic interaction. Furthermore, employment of UV illumination significantly increases active adsorption sites and enhances response and recovery kinetics. As a result, the developed NO2 sensor achieves fast responses of a few seconds and a limit of detection down to sub-ppb-level with the help of UV illumination. It also shows good linearly, operated in both air and oxygen-free environments, at both room or low temperature (238 K) conditions. The developed multi-framework offers an efficient and precision detection of NO2 with ultrafast responses and ultralow concentrations in multiple environments.

Mitigation of Cisplatin-Induced Nephrotoxicity and Augmentation of Anticancer Potency via Tea Polyphenol Nanoparticles' Codelivery of siRNA from CRISPR/Cas9 Screened Targets.

Cisplatin, a frontline chemotherapeutic agent against cancer, faces challenges in clinical application due to significant toxicities and suboptimal efficacy. Renal toxicity, a dose-limiting factor of cisplatin, results from multifactorial processes including cisplatin-induced cellular pyroptosis, oxidative damage, and inflammatory responses. Our findings reveal that Tea Polyphenols Nanoparticles (TPNs) derived from Epigallocatechin gallate (EGCG) effectively could address these diverse mechanisms, comprehensively alleviating cisplatin-induced nephrotoxicity. Leveraging TPNs as carriers, chemical conjugation enables the encapsulation of tetravalent cisplatin prodrug, extending its systemic half-life, enhancing tumor tissue accumulation, while simultaneously mitigating renal toxicity. Concurrently, employing a CRISPR/Cas9 kinase library, we identified CSNK2A1 as a target sensitizing tumor cells to cisplatin, enabling specific siRNA sequences to augment cisplatin susceptibility, thereby minimizing the dosage requirement. Benefiting from the versatile carrier properties of TPNs to codeliver cisplatin prodrug and anti-CSNK2A1 siRNA, we developed a codelivery system, Pt-TPNs/siRNA. Pt-TPNs/siRNA not only enhances the anticancer effects but also mitigates cisplatin-induced renal toxicity, achieving efficacy while reducing toxicity. Mechanistic and safety assessments of these nanoparticles were conducted at both cellular and animal levels, opening new avenues for improved clinical utilization of cisplatin.

Cyclotron resonance imaging at cryogenic temperatures enabled by electric field modification in a microwave cavity

Abstract Cyclotron resonance (CR) is a standard but emerging technique for investigating carrier properties of semiconductors. We have succeeded in CR measurements by employing a microwave cavity designed for electron paramagnetic resonance (EPR). Here, we demonstrate CR imaging to visualize the spatial distribution of carriers at cryogenic temperatures for the first time. To realize CR imaging, it is necessary to account for the electric field modification in the microwave cavity of a cylindrical TM110 mode, which is designed for EPR imaging and is inherently unsuitable for CR measurements. CR detection requires the oscillating electric field perpendicular to the external static magnetic field (B 0) at the sample position, which is not designed for the unloaded cavity. It has been challenging to verify the electric field distribution inside the cavity experimentally, but we show that the observation of the CR signals provides evidence of modification in the electric field. Analysis of the electromagnetic field explains the results, revealing a field distribution whose strength and direction are perturbed due to the lensing effect by the inserted dielectric materials.

Genetically modified extracellular vesicles loaded with activated gasdermin D potentially inhibit prostate-specific membrane antigen-positive prostate carcinoma growth and enhance immunotherapy

Prostate cancer (PCa) is associated with poor immunogenicity and lymphocytic infiltration, and immunotherapy effective against PCa remains unavailable. Pyroptosis, a novel immunotherapeutic modality for cancer, promotes systemic immune responses leading to immunogenic cell death in solid tumors. This paper describes the preparation and analysis of PSMAscFv-EVN-GSDMD; this genetically engineered recombinant extracellular vesicle (EV) expresses a single-chain variable antibody fragment (scFv) with high affinity for prostate-specific membrane antigen (PSMA) on their surfaces and is loaded with the N-terminal domain of gasdermin D (GSDMD). Both in vitro and in vivo, PSMAscFv-EVN-GSDMD effectively targeted PSMA-positive PCa cells and induced pyroptosis through the carrier properties of EVs and the specificity of PSMAscFv. In the 22RV1 and PSMA-transfected RM-1-inoculated PCa mouse models, PSMAscFv-EVN-GSDMD efficiently inhibited tumor growth and promoted tumor immune responses. In conclusion, PSMAscFv-EVN-GSDMD can convert the immunosuppressive “cold” tumor microenvironment of PCa into an immunogenic “hot” tumor microenvironment.

Charge Carrier Dynamics of SnO2 Electron‐Transporting Layers in Perovskite Solar Cells

Perovskite solar cells (PSCs) have demonstrated remarkable increase in their photovoltaic efficiencies over the past several years. Charge carrier properties including charge selectivity, extraction, and transport play key roles in device performances. Therefore, a comprehensive insight into the charge carrier dynamics and mobility within the bulk materials and at the interface is of great importance for the future development of this cutting‐edge technology. This review discusses the recent advances that have been made in SnO2 electron‐transporting layers and their limitations, followed by outlining the key development of novel strategies in improving SnO2 films through surface defect engineering, interface modification, and doping approaches. In addition, the recent developments are highlighted for identifying the origin of defect and trap center, and promoting SnO2 electron extraction and transporting capacity in PSCs. Importantly, the novel approaches are also discussed for studying photogenerated charge carrier dynamics of the devices. In conclusion, the own prospectives and outlooks are presented for the development of SnO2‐based PSCs, with a particular focus on addressing current difficulties in SnO2 and providing in‐depth understanding on the relationships between materials and devices.

Morphology and physicochemical properties of porous sago starch carriers produced by a variety of combination pre-treatment techniques

Morphology and physicochemical properties of porous sago starch carriers produced by a variety of combination pre-treatment techniques

Controlling the Intrinsic Charge Carrier Properties of Two-Dimensional Monochalcogenides (GeSe).

Strong anisotropy exhibited by materials, particularly in their low-dimensional forms, is a highly intriguing characteristic. In this study, we investigate the effects of geometrical potential and thermodynamics on the electronic properties of monolayer monochalcogenide charge carriers. First, the geometrical potential is introduced in a monolayer structure. We discuss the Fermi surface topology of materials and the effects of the geometrical potential on the low energy bands of 2D group-IV monochalcogenides around the Γ-point. Then, the temperature dependence of the carrier mobility of the monolayer is discussed along with predictions for its potential applications as nanomaterials.

Preparation of highly stable immobilized Candida antarctica lipase B (CALB) through adjusting the surface properties of carrier: Preparation, characterization and performance evaluation

The stability of the immobilized lipase is the key factor that determines the economy and feasibility of its industrial application. Here, two robust immobilized Candida antarctica lipase B (CALB) were prepared through adjusting the surface properties of ECR1030 resin. Silane coupling agent (SCA) and dialdehyde cellulose (DAC) were employed to modify the carrier surface. Contact angle measurement showed that the hydrophobicity of the modified carrier increased first, and then decreased with the increase of the chain length of SCA. FTIR results showed that Si-O-Si bond and aldehyde group were attached to ECR1030, respectively, indicating that the ECR1030 resin was successfully modified. Meanwhile, the NH and CN bond were observed in the corresponding immobilized CALB, suggesting CALB was immobilized onto the modified carriers. The effects of immobilization conditions on CALB immobilization was further investigated, and the C8-ECR1030-CALB and DAC-ECR1030-CALB with the activity of 12,736 U/g and 11,962 U/g were obtained. Moreover, the stability of the immobilized lipases was evaluated and compared with the commercial Novozym 435. The C8-ECR1030-CALB and DAC-ECR1030-CALB exhibited comparable or superior stability to Novozym 435 and showed better deacidification effect than Novozym 435. This study paves road for further study involving preparation of highly stable immobilized lipase.

Structure, morphology and surface properties of α-lactose monohydrate in relation to its powder properties

The particulate properties of α-lactose monohydrate (αLMH), an excipient and carrier for pharmaceuticals, is important for the design, formulation and performance of a wide range of drug products. Here an integrated multi-scale workflow provides a detailed molecular and inter-molecular (synthonic) analysis of its crystal morphology, surface chemistry and surface energy. Predicted morphologies are validated in 3D through X-ray diffraction contrast tomography. Interestingly, from aqueous solution fastest growth is found to lie along the b-axis, i.e. the longest unit cell dimension of the αLMH crystal structure reflecting the greater opportunities for solvation on the prism compared to the capping faces leading to their slower relative growth rates. The tomahawk morphology reflects the presence of β-lactose which asymmetrically binds to the capping surfaces creating a polar morphology. The crystal lattice energy is dominated by van der Waals interactions (between lactose molecules) with electrostatic interactions contributing the remainder. Predicted total surface energies are in good agreement with those measured at high surface coverage by inverse gas chromatography, albeit their dispersive contributions are found to be higher than those measured. The calculated surface energies of crystal habit surfaces are not found to be significantly different between different crystal surfaces, consistent with αLMH's known homogeneous binding to drug molecules when formulated. Surface energies for different morphologies reveals crystals with the elongated crystal morphologies have lower surface energies compared to those with a triangular or tomahawk morphologies, correlating well with literature data that the surface energies of the lactose carriers are inversely proportional to their aerosol dispersion performance.

ВЛИЯНИЕ ТЕПЛОФИЗИЧЕСКИХ СВОЙСТВ ТЕПЛОНОСИТЕЛЕЙ НА ПРОЦЕСС ТЕПЛООБМЕНА В ЗАМКНУТЫХ ДВУХФАЗНЫХ ТЕПЛОПЕРЕДАЮЩИХ СИСТЕМАХ

The analysis of low-temperature heat carriers (ozone-safe freons) properties for use as heat carriers in thermosyphon elements has been carried out. The most significant thermophysical properties of heat carriers that affect the intensity of heat exchange in closed two-phase heat-transfer devices have been determined. The calculation of the FOM quality index of the heat carrier for the selected freons is given. The dependence of the thermal resistance of the thermosyphon element on the supplied heat load is established. Recommendations are given for choosing a heat carrier for two-phase heat-transfer elements

Design of NiPS3/MoS2/rGO hybrid electrocatalyst for electrochemical hydrogen evolution

The design and development of efficient electrocatalysts for hydrogen evolution reaction is presently a pressing task to overcome future energy demands. In the present study a hybrid layered compound NiPS3/MoS2/rGO (NMR) is investigated as an electrocatalyst for hydrogen evolution reaction (HER). The metal trichalcogenidophosphates (MTPs), transition metal dichalcogenides and reduced graphene oxide materials based electrocatalysts are promising material for HER. The hybrid layered compound NMR displays good electrocatalytic activity in acidic medium in comparison to its counterparts MoS2/rGO and NiPS3/rGO with an overpotential and Tafel slope of 152 mV vs RHE and 75 mV/dec, whereas MoS2/rGO and NiPS3/rGO shows an overpotential of 206 mV and 223 mV vs RHE with a Tafel slope value of 146 mV/dec and 154 mV/dec respectively. The hybrid electrocatalyst exhibited high stability up to 1000 cycles with a stable current. The high HER activity of NMR is attributed to synergistic effect of electrocatalysts where P and S of NiPS3 acts as an appropriate hydrogen adsorption sites and catalytically active Mo edge sites of MoS2 with high charge carrier property of rGO contributed to enhanced hydrogen evolution reaction.

A simplified method of calculating heat flow through a heat exchanger with a significantly temperature-dependent specific heat of heat transfer fluids

A simplified method of calculating the heat flow through a heat exchanger in which one or both heat-carrying media have a specific heat that varies significantly with temperature is proposed. The proposed method allows for the calculation of the maximum heat flow rate provided that the thermodynamic properties of both heat carriers are known. It is intended for the simplification of heat exchanger modeling at the pre-design power plant simulations, which are used for the assessment of efficiency and the selection of schematic solutions. This is particularly relevant when the parameters of the heat exchangers are not known. The proposed method may prove useful for the simulation of binary cycle geothermal power plants, as well as for the modeling of gas turbine power plants utilizing carbon dioxide as the working medium for their cycles.

Investigation on the structure and properties of nanostructured lipid carriers loaded with different contents of phytosterols and their impact on lipid oxidation

In this study, nanostructured lipid carriers (NLCs) were prepared using walnut oil as a liquid lipid to load phytosterols (PS). The effects of different ratios of PS to lipids on the structural and functional properties of these carriers and lipid oxidation of PS-loaded carriers were investigated. The XRD, FTIR, and DSC results indicated that NLCs formulated with walnut oil as the liquid lipid were successful in incorporating PS. These NLCs exhibited a smaller average particle size (<300 nm) and a lower PDI (<0.3), along with a higher zeta potential. Furthermore, transmission electron microscopy (TEM) revealed that PS5-NLC displayed the most uniform particle size distribution and excellent dispersion. Notably, NLCs demonstrate high encapsulation efficiency and antioxidant capacity. Importantly, the bioaccessibility of PS in the carriers significantly increased from 23.5% to 86.8% compared with that of pure PS. Following a storage period of 21 days, the NLCs loaded with PS showed a lipid hydroperoxide (LH) value of 32.4 mmol/L and a malondialdehyde (MDA) content of 9.9 μmol/L, which were 13.6% and 33.3% lower, respectively, than those of the carriers without PS, indicating an effective reduction in lipid oxidation. This study is first to introduce the innovative use of walnut oil as a liquid lipid for preparing NLCs. It was observed that incorporating PS not only enhanced the bioaccessibility of these compounds but also effectively mitigated lipid oxidation. Overall, this study offers valuable insights into the development of PS delivery systems and broadens the potential applications of walnut oil.

In situ tracking anisotropic photocarrier dynamics in two-dimensional ternary Ta2NiSe5 via digital micromirror device-based pump-probe microscopy

In two-dimensional (2D) material studies, tracking the anisotropic ultrafast carrier dynamics is essential for the development of optoelectronic nano-devices. Conventionally, the anisotropic optical and electronic properties are investigated via either polarization-dependent Raman spectroscopy or field-effect transistors measurements. However, study of the anisotropic transient carrier behaviors is still challenging, due largely to the lack of picosecond-resolved acquisition or programmable scanning capabilities in the current characterization systems. In this work, we select Ta2NiSe5 as a model system to investigate the ultrafast anisotropic transportation properties of photo-excited carriers and transient polarized responses via a digital micromirror device (DMD)-based pump-probe microscope, where the probe beam scans along the armchair and zigzag directions of a crystal structure via binary holography to obtain distinct carrier diffusion coefficients, respectively. The results reveal the nonlinear diffusion behaviors of Ta2NiSe5 in tens of picoseconds, which are attributed to the interplay between excited electrons and phonons. The trend of the measured local polarization-dependent transient reflectivity is consistent with the polarized Raman spectra results. These results show that the DMD-based pump-probe microscope is an effective and versatile tool to study the optoelectronic properties of 2D materials.

2D hydrogen bonded organic framework (2D-HOF) in benzodioxane-coupled-pyridine as a charge carrier: Synthesis, structural, quantum computational investigation

This research presents a comprehensive investigation into the synthesis, structural features, and charge carrier properties of a novel 2D Hydrogen-Bonded Organic Framework (2D-HOF) formed by Benzodioxane-Coupled-Pyridine. The synthesis involves the reaction of 2,3-dihydrobenzo[b][1,4]dioxin-6-carbaldehyde with pyridine-2-carbohydrazide in the presence of acetic acid and ethanol solvent, leading to the formation of (E)-2-(2-((2,3-dihydrobenzo[b][1,4]dioxin-6-yl)methylene)hydrazinyl)pyridine (DDMP). Single crystal X-ray diffraction analysis reveals the monoclinic crystal system with the P21/n space group, showcasing a non-planar structure due to a distinctive twisting motion in the dioxane ring. The crystal packing is governed by a complex network of intermolecular interactions, including hydrogen bonds, short contacts, and π-stacking, ultimately forming a stable 2D-HOF. Hirshfeld Surface (HS) analysis provides insights into key interactions, emphasizing the significance of hydrogen bonding, short contacts, and stacking interactions in molecular packing. The 2D fingerprint (FP) plots quantitatively highlight crucial interatomic contacts, with hydrogen bonding, CH…H, and O…H interactions dominating. Molecular Electrostatic Potential (MEP) analysis reveals potential sites for electrophilic and nucleophilic attacks, aiding in predicting reactive sites and charge carrier behavior. Energy framework analysis sheds light on the pairwise interaction energies within the crystal structure, emphasizing the role of dispersive forces in stabilizing the crystal lattice. Density functional theory calculations indicate the molecule's charge transfer capabilities, suggesting its suitability for applications such as batteries, supercapacitors, and solar cells. Additionally, global reactivity parameters suggest that the 2D HOF material has electron and proton conduction capabilities, making it versatile for various applications. Atoms-in-molecules (AIM) topology analysis, particularly non-covalent interaction (NCI) analysis, provides a detailed understanding of intra and intermolecular interactions, highlighting hydrogen bonding and π…π interactions. H-bond binding energy analysis confirms the non-covalent nature of identified interactions, emphasizing their strength and significance.

Ni modified ZSM-5 promoted syngas production in chemical looping via the structural regulation of Ni particles under redox conditions

Chemical looping reforming of CH4 coupled with CO2 reduction stands out as a promising method for the syngas production. In this process, it is significant to design the oxygen carrier with high reactivity and stability. In this work, a highly efficient oxygen carrier is obtained by physically mixing Metal-modified ZSM-5 with LaFe0.85Ni0.15O3 (LFN). The physical and chemical properties of the oxygen carriers are characterized by XRD, Raman, XPS, BET, TEM, NH3-TPD, CO2-TPD and CH4-TPD techniques. It is noted that mesoporous structures are formed over the Ni modified ZSM-5, due to that part of Ni elements replace Al in the silicaluminate framework. The structure change of the ZSM-5 promotes the gas adsorption capacity. CH4 and CO2 cannot be adsorbed on the surface of ZSM-5, while Ni-modified ZSM-5 enhances the adsorption capacity for CO2 to a large degree. Moreover, Ni species are acted as active sites to facilitate the activation of CH4 and CO2 during the redox process. The aggregation-redispersion of Ni particles during the reduction-oxidation process inhibits the deactivation of Ni particles, which improves the stability of the oxygen carrier. Among all the obtained samples, LFN/10 wt% Ni-ZSM-5 exhibits the highest yields of syngas (8.38 mmol g−1) and CO (2.42 mmol g−1).

ESR, UV–vis–NIR and FTIR spectroscopic characterization of charge carriers in copper salen polymeric complexes

In this work, we present spectroscopic investigation of charge carriers in copper(II) salen-type polymeric complexes. The polymers comprising monomeric complexes of copper(II) ion with N2O2 Schiff base ligands are analyzed to understand the influence of the paramagnetic metal center and electron-donating substituents in the ligand on the spectroscopic properties of oxidized polymers. Potential-driven structural changes in the polymeric complexes were monitored using electron spin resonance (ESR), ultraviolet−visible − near infrared (UV−vis − NIR) and Fourier Transform Infrared (FTIR) spectroelectrochemistry. By EPR spectroelectrochemistry, we gained insight into the magnetic properties of charge carriers formed during the initial and deep oxidation of the polymers as well as the interactions between the Cu(II)–ligand spins and ligand–ligand ones. By FTIR spectroelectrochemistry, it has been shown that the charge in the low doped polymers is delocalized within the whole repeat unit.