Trapping Properties Research Articles

Aspalathin and Other Rooibos Flavonoids Trapped α-Dicarbonyls and Inhibited Formation of Advanced Glycation End Products In Vitro

The excessive dietary intake of simple sugars and abnormal metabolism in certain diseases contribute to the increased production of α-dicarbonyls (α-DCs), such as methylglyoxal (MGO) and glyoxal (GO), the main precursors of the formation of advanced glycation end products (AGEs). AGEs play a vital role, for example, in the development of cardiovascular diseases and diabetes. Aspalathus linearis (Burman f.) R. Dahlgren (known as rooibos tea) exhibits a wide range of activities beneficial for cardio-metabolic health. Thus, the present study aims to investigate unfermented and fermented rooibos extracts and their constituents for the ability to trap MGO and GO. The individual compounds identified in extracts were tested for the capability to inhibit AGEs (with MGO or GO as a glycation agent). Ultra-high-performance liquid chromatography coupled with an electrospray ionization mass spectrometer (UHPLC-ESI-MS) was used to investigate α-DCs' trapping capacities. To evaluate the antiglycation activity, fluorescence measurement was used. The extract from the unfermented rooibos showed a higher ability to capture MGO/GO and inhibit AGE formation than did the extract from fermented rooibos, and this effect was attributed to a higher content of dihydrochalcones. The compounds detected in the extracts, such as aspalathin, nothofagin, vitexin, isovitexin, and eriodictyol, as well as structurally related phloretin and phloroglucinol (formed by the biotransformation of certain flavonoids), trapped MGO, and some also trapped GO. AGE formation was inhibited the most by isovitexin. However, it was the high content of aspalathin and its higher efficiency than that of metformin that determined the antiglycation and trapping properties of green rooibos. Therefore, A. linearis, in addition to other health benefits, could potentially be used as an α-DC trapping agent and AGE inhibitor.

Synthesis of cyclodextrin‐based temperature/enzyme‐responsive nanoparticles and application in antitumor drug delivery

Nanocarrier systems including the lipid-based, silica nanoparticle (NP)-based, chitosan-based, cyclodextrin (CD)-based, and so forth were prepared based on the various stimulus containing redox, pH, temperature, enzymes, etc. The nanocarriers with dual stimuli-responsive properties can meet further practical and clinical applications due to their highly accurate and controllable response to the lesion site, good drug release effect, and weak side effects. Here, a temperature/enzyme-responsive nanocarrier was prepared based on seven-[6-(diaminodipropylamine)-6-deoxy] -β-CD (SA-β-CD) and lauroyl choline chloride (LCC). The SA-β-CD/LCC NPs showed trapping and releasing properties for the antitumor drug celastrol (CSL) in the synergy of the temperature/enzyme stimuli. Notably, the release rate of CSL-trapped NPs reached 94%, which is a relatively high value in numerous drug delivery systems using CSL as a drug model. Furthermore, cytotoxicity and apoptosis tests suggested that CSL-trapped NPs exhibited similar activity to intact CSL on five tumor cells. The dual response nanocarriers may pave a possible way for effectively targeted releasing anti-cancer drugs.

Broad-Spectrum Virus Trapping with Heparan Sulfate-Modified DNA Origami Shells.

Effective broadband antiviral platforms that can act on existing viruses and viruses yet to emerge are not available, creating a need to explore treatment strategies beyond the trodden paths. Here, we report virus-encapsulating DNA origami shells that achieve broadband virus trapping properties by exploiting avidity and a widespread background affinity of viruses to heparan sulfate proteoglycans (HSPG). With a calibrated density of heparin and heparan sulfate (HS) derivatives crafted to the interior of DNA origami shells, we could encapsulate adeno, adeno-associated, chikungunya, dengue, human papilloma, noro, polio, rubella, and SARS-CoV-2 viruses or virus-like particles, in one and the same HS-functionalized shell system. Additional virus-type-specific binders were not needed for the trapping. Depending on the relative dimensions of shell to virus particles, multiple virus particles may be trapped per shell, and multiple shells can cover the surface of clusters of virus particles. The steric occlusion provided by the heparan sulfate-coated DNA origami shells can prevent viruses from further interactions with receptors, possibly including those found on cell surfaces.

Irradiation Damage Independent Deuterium Retention in WMoTaNbV.

High entropy alloys are a promising new class of metal alloys with outstanding radiation resistance and thermal stability. The interaction with hydrogen might, however, have desired (H storage) or undesired effects, such as hydrogen-induced embrittlement or tritium retention in the fusion reactor wall. High entropy alloy WMoTaNbV and bulk W samples were used to study the quantity of irradiation-induced trapping sites and properties of D retention by employing thermal desorption spectrometry, secondary ion mass spectrometry, and elastic recoil detection analysis. The D implantation was not found to create additional hydrogen traps in WMoTaNbV as it does in W, while 90 at% of implanted D is retained in WMoTaNbV, in contrast to 35 at% in W. Implantation created damage predicted by SRIM is 0.24 dpa in WMoTaNbV, calculated with a density of atoms/cm. The depth of the maximum damage was 90 nm. An effective trapping energy for D in WMoTaNbV was found to be about 1.7 eV, and the D emission temperature was close to 700 °C.

Capacitance Temperature Dependence Analysis of GaN-on-Si Power Transistors

Many kinds of defects are present in the different layers of GaN-on-Si epitaxy. Their study is very important, especially because they play a significant role on the device characteristics. This paper investigates the cause of the temperature dependence of the output and Miller capacitance at three temperatures: 25 °C, 75 °C and 150 °C of GaN-on-Si power transistors. In particular, this study focuses on the temperature dependence of the depletion voltage seen in these characteristics due to the progressive depletion of the two-dimensional electron gas (2DEG) under the device field plates. First, variations of the epitaxial growth are studied, showing that the intrinsic carbon concentration does not play a significant role. Secondly, the deep acceptor trap origin of the temperature dependence is analyzed with a TCAD simulation study. Thirdly, by adjusting TCAD parameters and binding them with experimental concentrations to fit experimental data, trap properties were obtained. The comparison of these properties with the acceptor traps in the literature suggests that the origin is a gallium vacancy tied to oxygen atom(s) on the N site.

Strongly trapped space-inhomogeneous quantum walks in one dimension

Localization is a characteristic phenomenon of space-inhomogeneous quantum walks in one dimension, where particles remain localized around their initial position. The existence of eigenvalues of time evolution operators is a necessary and sufficient condition for the occurrence of localization, and their associated eigenvectors are deeply related to the amount of localization, i.e., the probability that the walker stays around the starting position in the long-time limit. In a previous study by authors, the eigenvalues of two-phase quantum walks with one defect were studied using a transfer matrix, which focused on the occurrence of localization (Quantum Inf. Process 20(5), 2021). In this paper, we introduce the analytical method to calculate eigenvectors using the transfer matrix and also extend our results to characterize eigenvalues not only for two-phase quantum walks with one defect but also for a more general space-inhomogeneous model. With these results, we quantitatively evaluate localization and study the strong trapping property by deriving the time-averaged limit distributions of five models studied previously.

Analysis of adiabatic trapping phenomena for quasi-integrable area-preserving maps in the presence of time-dependent exciters.

In this paper, results concerning the phenomenon of adiabatic trapping into resonance for a class of quasi-integrable maps and Hamiltonians with a time-dependent exciter are presented and discussed in detail. The applicability of the results about trapping efficiency for Hamiltonian systems to the maps considered is proven by using perturbation theory. This makes possible to determine explicit scaling laws for the trapping properties. These findings represent a generalization of previous results obtained for the case of quasi-integrable maps with parametric modulation, as well as an extension of the work by Neishtadt etal. [Regul. Chaotic Dyn. 18, 686 (2013)10.1134/S1560354713060087] on a restricted class of quasi-integrable systems with time-dependent exciters.

Charge Storage and Reliability Characteristics of Nonvolatile Memory Capacitors with HfO2/Al2O3-Based Charge Trapping Layers.

Flash memories are the preferred choice for data storage in portable gadgets. The charge trapping nonvolatile flash memories are the main contender to replace standard floating gate technology. In this work, we investigate metal/blocking oxide/high-k charge trapping layer/tunnel oxide/Si (MOHOS) structures from the viewpoint of their application as memory cells in charge trapping flash memories. Two different stacks, HfO2/Al2O3 nanolaminates and Al-doped HfO2, are used as the charge trapping layer, and SiO2 (of different thickness) or Al2O3 is used as the tunneling oxide. The charge trapping and memory windows, and retention and endurance characteristics are studied to assess the charge storage ability of memory cells. The influence of post-deposition oxygen annealing on the memory characteristics is also studied. The results reveal that these characteristics are most strongly affected by post-deposition oxygen annealing and the type and thickness of tunneling oxide. The stacks before annealing and the 3.5 nm SiO2 tunneling oxide have favorable charge trapping and retention properties, but their endurance is compromised because of the high electric field vulnerability. Rapid thermal annealing (RTA) in O2 significantly increases the electron trapping (hence, the memory window) in the stacks; however, it deteriorates their retention properties, most likely due to the interfacial reaction between the tunneling oxide and the charge trapping layer. The O2 annealing also enhances the high electric field susceptibility of the stacks, which results in better endurance. The results strongly imply that the origin of electron and hole traps is different—the hole traps are most likely related to HfO2, while electron traps are related to Al2O3. These findings could serve as a useful guide for further optimization of MOHOS structures as memory cells in NVM.

Pd/BEA hydrocarbon traps: Effect of hydrothermal aging on trapping properties and Pd speciation

Interest in Pd/zeolites as automobile exhaust catalysts has driven research focused on understanding the chemical environment of Pd active centers. Here, we studied the effects of hydrothermal deactivation on a Pd/BEA hydrocarbon trap. Hydrothermal aging (HTA) led to decreased ethylene storage capacity and oxidation activity. Characterization by x-ray absorption spectroscopy (XAS) and NOx adsorption indicated that for lower Si/Al ratio samples, the amount of ion exchanged Pd increased after HTA. Temperature programmed desorption of NOx after NO exposure revealed two desorption peaks, with a high temperature peak that increased in area with increased aging temperature. Based on infrared spectroscopy, XAS and reactor results, the high temperature desorption peak is consistent with NO stored on Pd+. The Pd+ formed during NO adsorption, existing originally as [Pd(OH)]+. This species was less active in ethylene storage and oxidation than the original Pd2+ species. [Pd(OH)]+ stored NOx to a higher temperature than Pd2+.

Influence of Ag Nanowires with Different Morphologies on Light Trapping Abilities and Optoelectronic Properties of Ag Nanowires/ZnO:Al Nanorods Composite Films

The Ag nanowires/ZnO:Al nanorods (Ag NWs/AZO NRs) composite films were prepared by the simple hydrothermal growth of AZO NRs on the AZO seed layer (SL) at the void regions among the Ag NWs. Distinctive morphology evolution of the Ag NWs depending on the mass of FeCl3⋅6H2O solution was observed on the AZO SL. The effect of Ag NWs with different morphologies on the structure, morphology, optoelectronic properties and light trapping abilities of Ag NWs/AZO NRs composite films was investigated systematically. In particular, the relationship between the morphology, light trapping and electrical properties of the composite films was analyzed in detail. When 7 g of FeCl3⋅6H2O solution was added, Ag NWs with a length of about 50 μM were generated, and the Ag NWs overlapped adequately with each other to form a network structure beneficial to conductivity. Meanwhile, the Ag NWs/AZO NRs composite films containing Ag NWs prepared with 7 g FeCl3⋅6H2O solution exhibited high TT (above 80%), high haze value (0.29) at 550 nm and low sheet resistance (5.9 Ω/sq), which can be employed as transparent electrodes for improving electrical and light trapping properties in solar cells.

Organic thin-film transistors with inkjet-printed electrodes on hydrophobic Teflon-AF gate dielectric with reversible surface properties

Printed organic thin-film transistors (OTFTs) are promising for flexible, low-cost electronics; however, a major challenge is that successive processing steps of multiple solution-processed layers can interfere with each other. In particular, hydrophobic fluoropolymers are a promising group of materials to fabricate gate dielectrics with low charge trap density and properties such as good thermal stability, chemical inertness, low dielectric constant, and water repellency. However, the main difficulty in incorporating hydrophobic fluoropolymers in printed electronic devices is their low surface energy. Plasma treatment is a common method for surface modification that renders these hydrophobic layers wettable to print subsequent layers. This plasma processing can also affect the interface with the organic semiconductor (OSC) and transistor performance, which is studied here for the first time. The morphological and surface chemical properties of Teflon amorphous fluoropolymer (Teflon-AF) films change after plasma treatment and gradually reverse after post-annealing of subsequent layers as demonstrated here. Here, we fabricate solution-processed OTFTs with Teflon-AF as the gate dielectric. We report OTFTs with inkjet-printed source and drain electrodes with a minimum channel length of 20 μm on Teflon-AF for the first time. We show that the annealing of the inkjet-printed electrodes changes the morphology and the surface chemistry of the Teflon-AF gate dielectric underneath, thus reversing the effect of the plasma. We show that this electrode post-annealing step can improve the transistor performance by improving the interface between the Teflon-AF gate dielectric and the OSC in terms of smoothness and hydrophobicity. The transistor parameters such as mobility, on/off current ratio, and threshold voltage all follow a trend explained here by the properties of the Teflon-AF films. Increasing the post-annealing temperature to just below complete surface reversibility decreases surface roughness and trap-sites created after plasma treatment leading to optimized device performance. We characterize the Teflon-AF surface with contact angle measurement, roughness measurement, Fourier transform infrared spectroscopy (FTIR), and x-ray photoelectron spectroscopy (XPS). This understanding of the reversibility of the Teflon-AF surface helps achieve optimal performance of devices and systems incorporating fluoropolymers. • The challenge of processing OTFT layers on hydrophobic dielectrics is addressed. • 20 μm channel OTFTs with inkjet-printed electrodes on hydrophobic dielectric are achieved. • Teflon-AF surface changes after plasma and reverses after post-annealing. • Electrode annealing changes the morphology and surface chemistry of the dielectric. • Electrode annealing can improve the gate dielectric/organic semiconductor interface.

Nature-Inspired 3D Spiral Grass Structured Graphene Quantum Dots/MXene Nanohybrids with Exceptional Photothermal-Driven Pseudo-Capacitance Improvement.

Solar‐thermal conversion is considered as a green and simple means to improve the performance of energy storage materials, but often limited by the intrinsic photothermal properties of materials and crude structure design. Herein, inspired by the unique light trapping effect of wide leaf spiral grass during photosynthesis, a biomimetic structural photothermal energy storage system is developed, to further promote the solar thermal‐driven pseudo capacitance improvement. In this system, three‐dimensional printed tortional Kelvin cell arrays structure with interesting light trapping property functions as “spiral leaf blades” to improve the efficiency of light absorption, while graphene quantum dots/MXene nanohybrids with wide photothermal response range and strong electrochemical activity serve as “chloroplast” for photothermal conversion and energy storage. As expected, the biomimetic structure‐enhanced photothermal supercapacitor achieves an ideal solar thermal‐driven pseudo capacitance enhancement (up to 304%), an ultrahigh areal capacitance of 10.47 F cm−2, remarkable photothermal response (surface temperature change of 50.1 °C), excellent energy density (1.18 mWh cm−2) and cycling stability (10000 cycles). This work not only offers a novel enhancement strategy for photothermal applications, but also inspires new structure designs for multifunctional energy storage and conversion devices.

Modulating mechanism on the temperature dependent resistivity of ceramic dielectrics and its advantage over polymer insulation

Volume resistivity of polymer dielectrics reduces significantly with the increase of temperature. As a result, in direct current (DC) power apparatus or electronic device, temperature gradient over the material can result in considerable electric field distortion which greatly threats the polymer insulation. Advanced ceramic dielectrics are promising to be alternative to polymer insulation to deal with this issue. In this paper, Al2O3 and Si3N4 ceramic materials with different ion doping concentrations have been manufactured. Temperature dependent resistivity characteristics of the ceramics are obtained and compared with typical polymer dielectrics. Conduction models of the ceramic dielectrics are applied to understand their temperature dependent resistivity and its modulating mechanism. Effect of ion doping on the temperature dependent resistivity has been obtained and analyzed which agrees well with their charge trapping property acquired by thermal stimulation depolarization current measurement, based on which the method to modulate the temperature stability of material resistivity have been proposed. Finally, a comprehensive comparison between ceramics and polymers in high voltage DC applications have been made which further proves the advantage of ceramic dielectrics.

Side-Chain Engineering of Polystyrene Dielectrics Toward High-Performance Photon Memories and Artificial Synapses

The emerging applications of organic field-effect transistors (OFETs), such as photon memories and artificial synapses, require polymer dielectrics with superior charge trapping properties. Despite the introduction of high-k and fluorinated polymers in the performance optimization of OFETs, there is still a lack of widely recognized acknowledgment between molecular structures and charge trapping characteristics, as well as no general principles in designing polymeric dielectrics for electronic memory devices. Here, we propose a series of fluorinated polystyrene isomers through side-chain engineering, namely, ortho-(o-), meta-(m-), and para-fluorinated polystyrene (p-FPS). The gradually enlarged intramolecular charge separation of o-, m-, and p-FPS enhances molecular electrostatic potential, which promotes polarization and charge trapping performances, resulting in an enlarged dielectric constant, as well as more deep traps toward stable electret. Subsequently, largely improved photon memory and artificial synapse performances of p-FPS-based OFETs further suggest the dominating role of dielectric side-chain structures on memory and synapse performances, leading to a recommendation of low-k (εr < 5) dielectric polymers with enhanced electrostatic potential for OFET-based memory devices and bionic nervous systems.

Excellent omnidirectional light trapping properties of inverted micro-pyramid structured silicon by copper catalyzed chemical etching

Nano/micro structuring of silicon (Si) attracts a lot of research interests for minimizing the reflective losses (>30%) of Si surface limiting the solar cell performance majorly. Here, arrays of inverted micro-pyramids Si (IP–Si) have been fabricated on large area of the solar-grade, as-cut Si wafers by a simple, one-step copper (Cu) catalyzed chemical etching (CuCCE) in aqueous etch bath of 5 mM-Cu(NO3)2/4.6M-HF/0.55M − H2O2 at 50 °C. Influence of etching time is investigated under constant etch bath parameters and starting surface properties of the Si wafers. The CuCCE mechanism is compared with the standard alkali (aq. KOH) texturing of Si(100) wafers. The formation of inverted structure is attributed to Cu nanoparticles catalyzed localized anisotropic as well as isotropic etching of Si(100) as compared to only anisotropic etching in the KOH texturing. The IP-Si surface offers a superior light trapping ability in broad spectral range compared to the conventional KOH based random upright micro-pyramids (UP–Si). The IP-Si surface could achieve solar weighted reflectance (SWR) as low as <7% in 400–1000 nm spectral range as compared to ∼14% of the UP-Si surfaces. This has been attributed to higher percentage of triple bounce interaction of the incident light with Si surface offered by the IP-Si. Further, the IP-Si offers enhanced omnidirectional light trapping for wide angle of incidence (AOI) of light (−40° to +40°) as compared to that in UP-Si. The enhanced omnidirectional light trapping of the IP-Si and its mechanism has further been explained by finite difference time domain (FDTD) simulation. Further, potential of IP-Si for enhanced solar cell performance is proposed on the basis of theoretical calculation of total photocurrent for planar, UP-Si and IP-Si surfaces. A simple, economic yet effective process for large area fabrication of the inverted micro/nano-pyramid arrays of Si with enhanced and broad band omnidirectional light trapping properties has been shown which has potential for efficient Si solar cell application.

Molecular-Scale Plasmon Trapping via a Graphene-Hybridized Tip-Substrate System.

We theoretically investigated the plasmon trapping stability of a molecular-scale Au sphere via designing Au nanotip antenna hybridized with a graphene sheet embedded Silica substrate. A hybrid plasmonic trapping model is self-consistently built, which considers the surface plasmon excitation in the graphene-hybridized tip-substrate system for supporting the scattering and gradient optical forces on the optical diffraction-limit broken nanoscale. It is revealed that the plasmon trapping properties, including plasmon optical force and potential well, can be unprecedentedly adjusted by applying a graphene sheet at proper Fermi energy with respect to the designed tip-substrate geometry. This shows that the plasmon potential well of 218 kBT at room temperature can be determinately achieved for trapping of a 10 nm Au sphere by optimizing the surface medium film layer of the designed graphene-hybridized Silica substrate. This is explained as the crucial role of graphene hybridization participating in plasmon enhancement for generating the highly localized electric field, in return augmenting the trapping force acting on the trapped sphere with a deepened potential well. This study can be helpful for designing the plasmon trapping of very small particles with new routes for molecular-scale applications for molecular-imaging, nano-sensing, and high-sensitive single-molecule spectroscopy, etc.

A Siloxene/Ecoflex Nanocomposite‐Based Triboelectric Nanogenerator with Enhanced Charge Retention by MoS2/LIG for Self‐Powered Touchless Sensor Applications (Adv. Funct. Mater. 27/2022)

Triboelectric Nanogenerators In article number 2113005, Jae Y. Park and co-workers develop a Siloxene/Ecoflex based contactless triboelectric nanogenerator (TENG) to reduce the possible contact situations and improve the robustness and functionality of the TENG. The MoS2/LIG-based charge trapping interlayer exhibits excellent charge trapping property and aids in the realization of the TENG as a self-powered sensor for touchless interactions.

Mechanism of ozone-improved surface flashover performance of epoxy composites

Surface flashover is a serious threat to the stable operation of advanced electrical applications. Ozone modification has recently been developed for improving the surface flashover performance. However, the effect of ozone on surface properties is still not fully elucidated. In this work, various concentrations of ozone are used to modify epoxy composites and their DC flashover voltages in SF6 at 0.1 MPa are evaluated. The results show that the flashover voltage of sample modified by 130 mg/L ozone for 4 h is improved by 22.6%, from 31.29 kV to 38.35 kV. It is proved to be highly related to the surface chemistry and trap properties. The X-ray photoelectron spectroscopy (XPS) spectra shows that some C–H and CC bonds on the surface are oxidized to C–O and CO bonds. The results of simulation and surface trap demonstrate that the oxidized C–O and CO bonds change the frontier orbitals and density of states, thus leading to a lower deep trap density. The lower trap density alleviates the generation of electron avalanche and eventually improves the flashover voltage. This work reveals the mechanism of ozone modification improving surface flashover voltage and provides a promising route to enhance the surface flashover performance.

Electro-optical trap for polar molecules

A detailed treatment of an electro-optical trap for polar molecules, realized by embedding an optical trap within a uniform electrostatic field, is presented and the trap's properties analyzed and discussed. The electro-optical trap offers significant advantages over an optical trap that include an increased trap depth and conversion of alignment of the trapped molecules to marked orientation. Tilting the polarization plane of the optical field with respect to the electrostatic field diminishes both the trap depth and orientation and lifts the degeneracy of the $\pm M$ states of the trapped molecules. These and other features of the electro-optical trap are explained in terms of the eigenproperties of the polar and polarizable molecules subject to the combined permanent and induced electric dipole interactions at play.

Multi-Layer High-K Gate Stack Materials for Low D&lt;sub&gt;it&lt;/sub&gt; 4H-SiC Based MOSFETs

Metal-oxide-semiconductor capacitors with single and multi-layer high-K gate dielectrics on Si (0001) face of n-type 4H-SiC substrates have been investigated. Multi-layered nanolaminated gate-stack comprises alternating ultrathin (6nm) Al2O3 and HfO2. A 5nm thick interfacial silicon oxynitride is deposited prior to laminated films to investigate interface trap properties and tuning of flat band voltage. Total thickness of gate-stack films including interfacial layer is 55nm. The thermal stability of multi-layered nanolaminated film is investigated using XTEM. Localized crystallization of HfO2 is visible after RTA at 900°C while Al2O3 remains fully amorphous. Some of HfO2 grains have extended into Al2O3 layer but was not able to crossover. The measured accumulation capacitance of 55nm thick gate dielectric gives an effective dielectric constant value of 9.6 and an equivalent oxide thickness of 22nm from high-frequency capacitance-voltage measurements. A positive flat band voltage ( of 12.2V and 10.6V are observed from both single layer HfO2 and Al2O3 dielectrics, respectively due to presence of negatively charged oxygen interstitial defects generated during atomic layer deposition process. However, VFB shifted towards negative voltage-7.6V for multi-layered Al2O3/HfO2 stacks probably associated with positive Al and Hf interstitials at interface of Al2O3/HfO2. Ultrathin interfacial oxynitride films is effective to reduce Dit to 3×1011/eVcm2 and tuning of VFB. The breakdown field of stacked gate dielectric on 4H-SiC is 10.0 MV/cm.