Enhancement Of Current Density Research Articles

Multi-sub-inlets at cathode flow-field plate for current density homogenization and enhancement of PEM fuel cells in low relative humidity

Multi-sub-inlets are proposed at the cathode flow-field plate (FFP) of a polymer electrolyte membrane (PEM) fuel cell to improve the current density homogeneity and overall cell performance. The cathode main inlets andsub-inlets arefed with humidified and dry air, respectively, for appropriate membrane hydration and enhanced water removal to maintain thecathodetotalflow rateat the same relative humidity. The influences of the number of sub-inlets and the sub-inlet flow rate (the amount of air from the sub-inlets) on the overall cell performance with cathode reactant relative humidity (RHc) of 0%, 10%, and 20% are numerically investigated using a 3D multiphase fuel cell model. Compared with the conventional parallel FFP design, a multi-sub-inlet parallel FFP design can relieve oxygen maldistribution, improve water removal ability and dissolved water content, and maintain a low pressure drop, increasing the homogeneity of current density and overall cell performance. The numerical results also indicate that a reasonable increase in the sub-inlet flow rate for upstream sub-inlets can further benefit the maximum power density while maintaining the homogeneity of oxygen distribution. Multi-sub-inlet parallel FFP designs with RHc of 10% and 20% exhibit no significant differences in the distributions of internal physical quantities and cell performance, although 10% RHc saves water for air humidification.

Redox behaviour of CaCl2 melts in presence of moisture as impurity. Part I: Cyclic voltammetry

• Redox behaviour of bare CaCl 2 melts -explored using cyclic voltammetry at 900 °C at inert tungsten electrode. • Effect of addition of CaCl 2 .2H 2 O and Ca(OH) 2 in CaCl 2 melt studied using cyclic voltammetry. • Peak current densities observed in bare melts enhanced with addition of CaCl 2 .2H 2 O or Ca(OH) 2 . • Complex reduction behaviour attributed to formation of CaOHCl in melt at high temperatures. • Peak analysis of cyclic voltammograms and semi-integral curves carried out; cathodic reduction mechanism proposed. Redox behaviour of CaCl 2 melt at 900 °C is well known; what is not completely established so far is how the voltammetric behaviour of melt would be in presence of moisture. CaCl 2 prepared from vacuum drying of CaCl 2 .2H 2 O retained some residual moisture that eventually led to formation of CaOHCl at 900 °C as a result of which two redox couples were observed in the cyclic voltammograms at tungsten electrode. In order to decipher whether the redox peaks were a reflection of formation of single electro-active species, CaCl 2 .2H 2 O and Ca(OH) 2 were added in pre-electrolysed CaCl 2 melts and those were again analysed by cyclic voltammetry. Enhancement of peak current density of redox peaks, which were observed in pre-electrolysed CaCl 2 melt, was seen. This was attributed to the increased concentration of CaOHCl in the melt in presence of CaCl 2 .2H 2 O and Ca(OH) 2 . Subsequent to voltammetric peak analysis and logarithmic analysis of semi-integral curves for all melts, a mechanism involving formation of ( CaOH ) 2 2 + adsorbed undergoing a one-step two-electron transfer process in the first redox step was proposed. Second redox step resulted due to adsorption of O 2 - on tungsten, and its peak current density also got enhanced due to addition of CaCl 2 .2H 2 O and Ca(OH) 2 in melt.

Efficiency‐Enhanced Scalable Organic Photovoltaics Using Roll‐to‐Roll Nanoimprint Lithography

Light-trapping nanostructures have for decades been researched as a route to enhance the performance of organic solar cells (OSCs). Whereas the power conversion efficiencies (PCEs) of OSCs have reached above 18 %, industrially compatible devices made by scalable processing in air, using only nontoxic solvents and materials, have shown significantly lower performance values. Although light-trapping nanostructures may improve this, the methods for integrating the nanostructures are typically not compatible with industrial scale up. In this work, scalable, industrially compatible, nonfullerene-based OSCs are developed with integrated light-trapping nanostructures at the back electrodes in the devices. The OSCs are made by using scalable roll-to-roll (R2R) and sheet-to-sheet (S2S) processes and the nanostructures are made by using roll-to-plate (R2P) nanoimprint lithography. A fully scalable solution is thereby developed for industrially compatible nanostructured OSCs. The nanostructured devices show enhancements in PCE up to 25 % compared to reference cells, owing to an enhancement in the short-circuit current density (15 %) by enhanced absorption, and improved charge carrier extraction leading to an enhancement in the fill factor (7 %). Optical modeling is utilized to verify the optical effect of the nanostructures. The best devices attain a PCE of 6.5 %, which is the highest reported efficiency for air-processed slot-die coated ITO-free flexible PBDB-T : ITIC devices, here using nontoxic solvents.

Interpenetrating structure for efficient Sb2Se3 nanorod array solar cells loaded with CuInSe2 QDs sensitizer

The strong anisotropic electrical properties of one-dimensional (1D) nanostructure semiconductors, especially the anisotropic carrier transport, have a negative and significant influence on the performance of solar cells if the nanostructures have random orientation. Considering the advantages of nanorod solar cells in carrier transport, we have achieved growth of vertically aligned Sb2Se3 nanorod array with highly (hk1) orientation on CdS substrate, and constructed superstrate nanorod solar cells for the first time. The Sb2Se3 nanorod array solar cells exhibit the more efficient and long-range carrier transport in vertical direction. Furthermore, in order to suppress interface recombination, a CuInSe2 quantum dots (QDs) sensitizer has been applied to fill the volume between the nanorods completely, thus forming an interpenetrating nanocomposite structure. The CuInSe2 QDs can harvest additional light by absorption of visible light and contribute photocurrent. Meantime, the QDs function as a hole transport material and thus reduce the dependence of lateral transport. Consequently, the interpenetrating nanocomposite CuInSe2/Sb2Se3 solar cells display a power conversion efficiency of 7.54% with significant enhancements in the short-circuit current density and open-circuit voltage over pure Sb2Se3 nanorod cells. This is the highest efficiency for superstrate solar cells based on Sb2Se3 nanorod arrays.

Space charge limited current for bipolar flow in a crossed-field vacuum gap

In this paper, a numerical iteration approach is proposed to make an investigation of the influence of a transverse magnetic field on the space charge limited bipolar flow in a planar vacuum diode. By employing the method, the unknown limiting current density and potential distribution can be simultaneously determined. Considering a planar ion vacuum diode with a transverse magnetic field B parallel to the electrodes surface, we investigated the limiting current density as a function of B. Numerical calculations show that the limiting current density of the crossed-field vacuum diode may be approximately given by Je=JCL[a(B/BH)b+F], where JCL is the CL law and BH the Hull cutoff magnetic field, and a and b are the function of the ion current density, respectively. The physical meaning of F may be interpreted as the 1D current density enhancement factor due to the effect of ions for B=0. In the absence of ions, the limiting current solution is recovered in a crossed-field vacuum gap.

Pressure Dependence of Superconducting Properties, Pinning Mechanism, and Crystal Structure of the Fe0.99Mn0.01Se0.5Te0.5 Superconductor.

We have investigated the pressure (P) effect on structural (up to 10 GPa), transport [R(T): up to 10 GPa], and magnetic [(M(T): up to 1 GPa)] properties and analyzed the flux pinning mechanism of the Fe0.99Mn0.01Se0.5Te0.5 superconductor. The maximum superconducting transition temperature (Tc) of 22 K with the P coefficient of Tc dTc/dP = +2.6 K/GPa up to 3 GPa (dTc/dP = −3.6 K/GPa, 3 ≤ P ≥ 9 GPa) was evidenced from R(T) measurements. The high-pressure diffraction and density functional theory (DFT) calculations reveal structural phase transformation from tetragonal to hexagonal at 5.9 GPa, and a remarkable change in the unit cell volume is observed at ∼3 GPa where the Tc starts to decrease, which may be due to the reduction of charge carriers, as evidenced by a reduction in the density of states (DOS) close to the Fermi level. At higher pressures of 7.7 GPa ≤ P ≥ 10.2 GPa, a mixed phase (tetragonal + hexagonal phase) is observed, and the Tc completely vanishes at 9 GPa. A significant enhancement in the critical current density (JC) is observed due to the increase of pinning centers induced by external pressure. The field dependence of the critical current density under pressure shows a crossover from the δl pinning mechanism (at 0 GPa) to the δTc pinning mechanism (at 1.2 GPa). The field dependence of the pinning force at ambient condition and under pressure reveals the dense point pinning mechanism of Fe0.99Mn0.01Se0.5Te0.5. Moreover, both upper critical field (HC2) and JC are enhanced significantly by the application of an external P and change over to a high P phase (hexagonal ∼5.9 GPa) faster than a Fe0.99Ni0.01Se0.5Te0.5 (7.7 GPa) superconductor.

Optically photoactive Cu–In–S@ZnS core-shell quantum dots/biopolymer sensitized TiO2 nanostructures for sunlight energy harvesting

Colloidal semiconductor quantum dots (QDs) have been intensively investigated because of their remarkable tunable optical and electrical properties for potential clean energy production through solar photoconversion devices. Herein, we present for the first time the design and development of a hybrid nanostructure for applications in sunlight energy photoconversion, relying on a “safe and sustainable by design (SSD)” strategy, as follows: a) “Cadmium-free” (non-Cd-containing) inorganic semiconductor quantum dots (QDs), as optically active nanomaterials composed of quaternary Cu–In–S/ZnS systems (ZCIS); b) carboxylic-functionalized cellulose derivative (CMC) as biopolymer ligand and macromolecular stabilizing agent; c) A green chemistry approach based on an aqueous synthesis at mild conditions (e.g., pH, temperature, “organic-free”, nontoxic precursors) for creating water-soluble supramolecular colloidal core-shell nanostructures (i.e., [email protected], core: ZCIS; shell: CMC); d) As a proof-of-concept, the fabrication of a photoelectrochemical cell (PEC-cell) based on a solid-liquid heterojunction using the photoanode composed of TiO2 sensitized by [email protected] nanohybrids. Regarding optical properties, the results demonstrated that the [email protected] nanohybrids presented absorption/emission characteristics with maxima responses within the visible range of the light spectrum, which is prospectively appropriate for sunlight photoconversion applications. The solid-liquid junction photoelectrochemical cells (PEC-cell) fabricated using TiO2 films deposited onto ITO glass slides sensitized by ZCIS QDs evidenced photoactivity under visible light illumination using “dark” (“OFF”) and “light” (“ON”) cycles. Moreover, the PEC-cells confirmed the significant enhancement of photoinduced current density (over 150%) upon illumination when the relative sensitization density associated with the ZCIS QDs/TiO2 ratio was increased, and ethanol was used as the co-solvent. The results were credited to better contact between ZCIS QDs and TiO2 nanoparticles, tailoring a more favorable energy level alignment at the heterojunction interfaces, promoting the formation of a cascade of conduction band edges. Thus, these quantum dot-sensitized nanostructures developed through a sustainable and biocompatible approach produced strictly via green chemistry process can be anticipated as a sustainable alternative to the existing heavy metal-based sunlight photoactive optical nanomaterials after further optimization of conversion efficiency parameters.

Harvesting Sub-bandgap Photons via Upconversion for Perovskite Solar Cells.

Lanthanide-based upconversion (UC) allows harvesting sub-bandgap near-infrared photons in photovoltaics. In this work, we investigate UC in perovskite solar cells by implementing UC single crystal BaF2:Yb3+, Er3+ at the rear of the solar cell. Upon illumination with high-intensity sub-bandgap photons at 980 nm, the BaF2:Yb3+, Er3+ crystal emits upconverted photons in the spectral range between 520 and 700 nm. When tested under terrestrial sunlight representing one sun above the perovskite's bandgap and sub-bandgap illumination at 980 nm, upconverted photons contribute a 0.38 mA/cm2 enhancement in the short-circuit current density at lower intensity. The current enhancement scales non-linearly with the incident intensity of sub-bandgap illumination, and at higher intensity, 2.09 mA/cm2 enhancement in current was observed. Hence, our study shows that using a fluoride single crystal like BaF2:Yb3+, Er3+ for UC is a suitable method to extend the response of perovskite solar cells to near-infrared illumination at 980 nm with a subsequent enhancement in current for very high incident intensity.

Evolution of structural and optoelectronic properties in fluorine–aluminum co-doped zinc oxide (FAZO) thin films and their application in CZTSSe thin-film solar cells

The window layer is an important layer that transmits sunlight and generates electric current as the carriers move. Aluminum (Al) -doped zinc oxide (AZO) has been widely applied as the window layer in thin-film solar cells (TFSCs) owing to its favorable optoelectronic properties, as its properties can be controlled and further improved with suitable dopants. In this study, we strategically co-dope Al and fluorine (F) in ZnO thin films (FAZO) to improve the transmittance with controlled carrier concentration. To study the influence of F dopant on the structural, optical, and electrical properties of FAZO thin films, the F doping concentration is varied (0–1.5%) while keeping the Al content fixed (2%). With increasing F doping concentration, the carrier concentration, transmittance, and bandgap values increase, whereas, the sheet resistance and resistivity of the single-layer FAZO thin films decrease, compared to the reference AZO film. The addition of a small amount of F alters the surface roughness with increasing concentration. The properties of the single-layer FAZO thin films show deteriorated properties at the highest doping concentration (1.5%). Under the optimum condition of 1% F, FAZO thin films exhibit the lowest sheet resistance of 5.84 Ω/sq, in addition to the highest transmittance of 89.3% in the visible light region. Furthermore, the FAZO thin films applied in Cu2ZnSn(S,Se)4 (CZTSSe) device shows significant enhancements in the short-circuit current density (Jsc) and fill factor (FF), resulting in improved device performance from ~8 to 9.57%.

Three-Dimensional Modeling of Anode-Supported Planar SOFC with Corrugated Electrolyte

The aim of this work is to analyze the effect of corrugated electrolyte on the cell performance. The corrugated electrolyte is applied to the traditional anode-supported planar solid oxide fuel cell (SOFC) based on the theory of mesoscale electrode-electrolyte interface modification. Three-dimensional models of SOFCs with electrolytes with different corrugation heights and periods are developed. In order to better understand the influence mechanism of corrugated electrolyte, not only the effect of the corrugated electrolyte on the overall cell performance is analyzed, but also the local gas distribution, concentration polarization, activation polarization, exchange current density and electron current density are discussed. The results show that the corrugated electrolyte leads to a decrease in the local exchange current density, but the enlargement of the activation reaction zone leads to an increase in the total charge transfer, thereby resulting in an improvement in cell performance. The enhancement of average current density with an expansion factor of 2 has a maximum value of 56.9% at an operating voltage of 0.7 V.

Development of arsenic doped Cd(Se,Te) absorbers by MOCVD for thin film solar cells

Recent developments in CdTe solar cell technology have included the incorporation of ternary alloy Cd(Se,Te) in the devices. CdTe absorber band gap grading due to Se alloying contributes to current density enhancement and can result in device performance improvement. Here we report Cd(Se,Te) polycrystalline thin films grown by a chamberless inline atmospheric pressure metal organic chemical vapour deposition technique, with subsequent incorporation in CdTe solar cells. The compositional dependence of the crystal structure and optical properties of Cd(Se,Te) are examined. Selenium graded Cd(Se,Te)/CdTe absorber structure in devices are demonstrated using either a single CdSe layer or CdSe/Cd(Se,Te) bilayer (with or without As doping in the Cd(Se,Te) layer). Cross-sectional TEM/EDS, photoluminescence spectra and secondary ion mass spectroscopy analysis confirmed the formation of a graded Se profile toward the back contact with a diffusion length of ~1.5 μm and revealed back-diffusion of Group V (As) dopants from the CdTe layer into Cd(Se,Te) grains. Due to the strong Se/Te interdiffusion, CdSe in the Se bilayer configuration was unable to form an n-type emitter layer in processed devices. In situ As doping of the Cd(Se,Te) layer benefited the device junction quality with current density reaching 28.3 mA/cm 2 . The results provide useful insights for the optimisation of Cd(Se,Te)/CdTe solar cells. Compositional control of optical band gap in Cd(Se,Te) thin films (0 ≤ x ≤ 1) (left) and the Se profile in finished Cd(Se,Te) devices (right) fabricated by MOCVD. • Cd(Se,Te) thin films (0 ≤ x ≤ 1) deposited with linear compositional control using a chamber-less MOCVD process. • CdSe-only and CdSe/CdSe 0.2 Te 0.8 bilayers utilised for Cd(Se,Te) grading in devices. • In-situ and ex-situ group V (arsenic) doping of the graded Cd(Se,Te) obtained. • Device performance improved for thinner CdSe layers and in-situ doped bilayers. • Good control of Se profile achieved via CdSe and CdSe/CdSe 0.2 Te 0.8 properties.

Promoting exsolution of RuFe alloy nanoparticles on Sr2Fe1.4Ru0.1Mo0.5O6\u2212\u03b4 via repeated redox manipulations for CO2 electrolysis

Metal nanoparticles anchored on perovskite through in situ exsolution under reducing atmosphere provide catalytically active metal/oxide interfaces for CO2 electrolysis in solid oxide electrolysis cell. However, there are critical challenges to obtain abundant metal/oxide interfaces due to the sluggish diffusion process of dopant cations inside the bulk perovskite. Herein, we propose a strategy to promote exsolution of RuFe alloy nanoparticles on Sr2Fe1.4Ru0.1Mo0.5O6−δ perovskite by enriching the active Ru underneath the perovskite surface via repeated redox manipulations. In situ scanning transmission electron microscopy demonstrates the dynamic structure evolution of Sr2Fe1.4Ru0.1Mo0.5O6−δ perovskite under reducing and oxidizing atmosphere, as well as the facilitated CO2 adsorption at RuFe@Sr2Fe1.4Ru0.1Mo0.5O6−δ interfaces. Solid oxide electrolysis cell with RuFe@Sr2Fe1.4Ru0.1Mo0.5O6−δ interfaces shows over 74.6% enhancement in current density of CO2 electrolysis compared to that with Sr2Fe1.4Ru0.1Mo0.5O6−δ counterpart as well as impressive stability for 1000 h at 1.2 V and 800 °C.

Anisotropic Critical Current Densities in Ba0.6K0.4Fe2As2 with Splayed Columnar Defects

Enhancement and non-monotonic field dependence of critical current density (Jc ), called anomalous peak effect, were observed in Ba1−x K x Fe2As2 with splayed columnar defects. In principle, anisotropy of in-plane Jc should be present in this superconductor since the introduced splayed columnar defects introduce anisotropy in the plane. This study reports in-plane anisotropy of Jc observed in 2.6 GeV U irradiated Ba0.6K0.4Fe2As2 with splay angles of ±15° and ±20°. Results show that Jc component parallel to the splay plane is larger than the perpendicular component, and the parallel component contribute to the anomalous peak effect at around B Φ/3 more.

Laser induced core–shell liquid metal quantum dots for high-efficiency carbon-based perovskite solar cells

Metal particles with excellent conductivity can be used as additives to ameliorate the performance of perovskite solar cells (PSCs). However, it is formidable to generate stable liquid metal particles especially quantum dots because of the room-temperature fluidity. Herein, in this work, eutectic gallium-indium liquid metal quantum dots (GIQDs) were prepared via pulsed laser irradiation in anti-solvent and incorporated in perovskite film to accelerate electron transport due to the superior conductivity. As a result, the charge transport resistance was decreased, leading to the fast quenching effect and short carrier lifetime at the surface of perovskite film, which were verified by steady-state and time-resolved photoluminescence. Besides, the reduced charge recombination contributed to the enhancement of current density. Moreover, after the optimization of 0.1 mg/mL GIQDs incorporated in perovskite film, the power conversion efficiency of PSCs obtained a champion value of 15.55%, which improved 17.18% when compared with pristine samples of 13.27%. This article will pave the way for binary liquid metal synthesizing and optoelectronic applications.

Evolution of Superconducting Properties of Coexistent Bi-2212 and Bi-2223 phases in BSCCO

The evolution of superconducting properties of BSCCO superconductors, inadvertently hosting the two superconducting phases Bi-2212 and Bi-2223 have been investigated in pristine and Pb doped BSCCO. The superconducting transition temperature TC of Bi-2212 phase monotonically increases with increasing Bi-2223 phase fraction. On the other hand Bi-2223 phase exhibits depression in TC for its lower phase fractions (<24%) but attains its bulk value as Bi-2223 phase fraction is increased to 30%. This behavior has been rationalized by invoking the interplay of proximity effects between the two coexisting phases and establishment of Bi-2223 superconducting percolation path. In addition to aiding the formation of BSCCO with higher Bi-2223 phase fraction, the Pb substitution also leads to an enhancement of critical current density by the creation of pinning centres.

Enhanced sensitivity of caterpillar-like ZnO nanostructure towards amine vapor sensing

Owing to the uprising health issues due to amine exposure, this work has been taken up to design a novel caterpillar-like ZnO nanoarchitecture using a combined hydrothermal and Forcespinning® technology for sensing amine vapor. This study presents two different approaches to investigate the sensing behavior of the caterpillar-like ZnO nanostructure compared to both commercially available ZnO nanoparticles and laboratory synthesized carbon/ZnO composite fibers. It is found that ZnO caterpillar-like nanostructure shows the best performance owing to its highest surface to volume ratio. Electrochemical investigations suggest maximum enhancement in current density from the caterpillar-like ZnO nanostructure on amine exposure due to the increased involvement of electron pair of nitrogen owing to its high hydroxyl concentration. Photoluminescence spectroscopy depicts defect induced blue emission owing to defect in native ZnO nanoparticles which quenches on amine exposure. The quenching has been found to be monotonic over the entire range of exposed n-propyl amine (NPA, 0–500 ppm) and attributed to defect annihilation upon exposing to amine vapor. Optical detection of NPA by the caterpillar-like ZnO nanostructure based on emission quenching shows a linear response in the studied NPA concentration range with a detection limit (LOD) of 12.54 ppm. Our results demonstrate the importance of structure, morphology and architecture of ZnO for gas sensing activity.

Unprecedented solar water splitting of dendritic nanostructured Bi2O3 films by combined oxygen vacancy formation and Na2MoO4 doping

We demonstrate the synergetic effect of Na2MoO4-doping and vacuum-annealing on dendritic nanostructured bismuth oxide (Bi2O3) thin films prepared by electrodeposition for visible-light-assisted photoelectrochemical (PEC) water oxidation. After evaluating various extents of Na2MoO4-doping as well as vacuum-annealing temperatures, it was evidenced that both Na2MoO4-doping and vacuum-annealing significantly improved the efficiency and PEC water oxidation performance. Compared to the undoped Bi2O3 photoanode, the optimized Na2MoO4-doped Bi2O3, after vacuum-annealing, resulted in more than 25-fold enhancement in the photoanodic current density to 1.06 mA/cm2 at 1.23 VRHE under AM1.5 G illumination. The PEC enhancement is credited mainly to the increased PEC surface active sites in the Na2MoO4-doped vacuum annealed sample. Confirmed by combined XPS and Mott-Schottky (M − S) analysis, vacuum annealing resulted in surface oxygen vacancies that can contribute to the photocatalytic activity. Besides, Na2MoO4-doping resulted in reduced dimensions of the dendritic structure, revealed by FE-SEM and XRD measurements, resulting in larger surface area and, therefore, larger surface/electrolyte contact. This dual strategy (metal doping + vacuum annealing) can be generalized to assemble photoanodes of other materials used for the production of solar fuels. Our results make a valuable step towards efficient Bi2O3/BiVO4 pn heterojunctions.

Current density enhancement for quantum dot-sensitized solar cells by modulation on the quantum dot loading amount of anatase nanowire array photoelectrodes

Current density enhancement for quantum dot-sensitized solar cells by modulation on the quantum dot loading amount of anatase nanowire array photoelectrodes

Photocatalytic and photoelectrocatalytic properties of Eu(III)-doped perovskite SrTiO3 nanoparticles with dopant level approaches

Eu(III) ion dopant exhibits unique luminescence depending on the local dopant environment in a host matrix. In the present study, Eu(III)-doped strontium titanate (SrTiO3) nanoparticles were synthesized and their catalytic activities were demonstrated to examine the roles of dopants in photocatalytic CO2 reduction, photocatalytic organic pollutant degradation and photoelectrocatalytic oxygen evolution reaction. The fundamental properties were characterized by X-ray diffraction crystallography, scanning electron microscopy, high resolution transmission electron microscopy, UV–visible absorption, Raman spectroscopy, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy (XPS). CO2 reduction products were observed to be mainly methanol, CO and CH4 with minor C2 compounds. Photocatalytic dye degradation showed the order of methyl orange < rhodamine B < methylene blue. The catalytic performances were found to be dependent on the Eu doping levels. Photoelectrocatalytic activities were tested by linear sweep voltammetry under 395 nm light which corresponds to the direct 5L6 ← 7F0 transition of Eu(III). Consequently, undoped SrTiO3 showed the highest enhancement in current density. Eu(III) ion was appeared to be initially doped in Sr(II) site confirmed by photoluminescence and XPS profiles. Ti(IV) oxidation state was also impacted by Eu(III) doping. The various tests demonstrated that Eu(III)-dopant could be a very useful probe for the elucidation of local environmental site and the dopant-role on catalytic activities.

Energy Dissipation via Magnetic Reconnection Within the Coherent Structures of the Magnetosheath Turbulence

AbstractA series of intermittent coherent structures was observed in magnetosheath turbulence in the form of magnetic peaks. These magnetic peaks are always accompanied with enhancement of local current density, and three of them are studied in detail because of their intense current density. Based on the magnetic field signals, magnetic curvatures, and the toroidal magnetic field lines, three peaks are identified as magnetic flux ropes. In each trailing part of these three peaks, an extremely thin electron current layer was embedded within a much broader ion‐scale current layer. The energy dissipation is evident within the peaks and direct evidence of magnetic reconnection was found within the thinnest electron current layer. The electrons were heated mainly in two regions of magnetic peaks, that is, the reconnecting current layer by parallel electric field and the trailing edges by Fermi and betatron mechanisms. These results suggest that the ion‐scale magnetic peaks are coherent structures associated with energy dissipation and electron heating in the magnetosheath. Thin current layers can be formed in magnetic peaks, and magnetic reconnection can play a significant role for the energy dissipation in magnetic peaks.