Current Collection Efficiency Research Articles

Investigation of proton radiation damage effects on the n-Fz DSSSD for the Phase I Upgrade of new Si Tracker at the R3B experiment

Radiation hard Double Sided Silicon Strip Detectors are used at the Silicon Tracker for the detection of two-dimensional position andenergy measurement of the incident protons in the R3B experiment at FAIR. Double Sided Silicon Strip Detectors were fabricated by Micron Semiconductor Ltd., U.K. and the first set of experimental measurements havebeenperformed on the non-irradiated detectors in order to understand the macroscopic performance of the detectors for the tracker. This study is extended to the performance of the irradiated detectors in the proton radiation environmentusing proton radiation damage model. The detectors were irradiated with 23 MeV protons up to an expected fluence of 8 × 1014 neq cm-2, which is one order higher than expected fluence at an initial phase0 of the experiment. The performance characteristics of the detectors on the full depletion voltage, leakage current, and charge collection efficiency were extrapolated using SRH and CCE modelling, which is usually implemented in device TCAD. The results on the detectors were compared with the available experimental data on the detectors. A very good comparison between experimental data and calculated resulthave been recorded for non-irradiated and irradiated detectors. The agenda is to propose a proton radiation hard Double Sided Silicon Strip Detector design on the basis of the present study for the phase 1 upgrade of the experiment.

Armoring hydrophilic wood-structured ultrathick electrode with bimetallic nitride enables high energy-density supercapacitor

Thick electrodes can reduce the ratio of inactive constituents in a holistic energy storage system while improving energy and power densities. Unfortunately, traditional slurry-casting electrodes induce high-tortuous ionic diffusion routes that directly depress the capacitance with a thickening design. To overcome this, a novel 3D low-tortuosity, self-supporting, wood-structured ultrathick electrode (NiMoN@WC, a thickness of ∼1400 μm) with hierarchical porosity and artificial array-distributed small holes was constructed via anchoring bimetallic nitrides into the monolithic wood carbons. Accompanying the embedded NiMoN nanoclusters with well-designed geometric and electronic structure, the vertically low-tortuous channels, enlarged specific surface area and pore volume, superhydrophilic interface, and excellent charge conductivities, a superior capacitance of NiMoN@WC thick electrodes (∼5350 mF cm−2 and 184.5 F g−1) is achieved without the structural deformation. In especial, monolithic wood carbons with gradient porous network not only function as the high-flux matrices to ameliorate the NiMoN loading via cell wall engineering but also allow fully-exposed electroactive substance and efficient current collection, thereby deliver an acceptable rate capability over 75% retention even at a high sweep rate of 20 mA cm−2. Additionally, an asymmetric NiMoN@WC//WC supercapacitor with an available working voltage of 1.0–1.8 V is assembled to demonstrate a maximum energy density of ∼2.04 mWh cm−2 (17.4 Wh kg−1) at a power density of 1620 mW cm−2, along with a decent long-term lifespan over 10,000 charging-discharging cycles. As a guideline, the rational design of wood ultrathick electrode with nanostructured transition metal nitrides sketch a promising blueprint for alleviating global energy scarcity while expanding carbon-neutral technologies.

Landfill gas collection efficiency: Categorization of data from existing in-situ measurements

Landfill methane emissions are commonly estimated using cover-type dependent default collection efficiency values, with a first-order decay model or measured gas collection. Current default collection efficiencies used in the United States were predominately derived from 4 studies conducted during or prior to 2007 that relied on flux chambers. Flux chambers are limited by small sample sizes, placement restrictions, and the inability to measure emissions from gas or leachate collection systems. Since 2007, over 14 new studies have been completed using more advanced technologies that allow for direct measurement of methane plumes from most or all of a landfill’s surface. On average, these measurements are 2–3 times greater than emissions predicted by current models and collection efficiency defaults. In lieu of measuring emissions from all landfills, updating collection efficiency defaults can bring modeled emissions into better alignment with measurements. To this end, collection efficiency estimates derived from measured data were categorized into cover types and then adjusted to account for cases where whole plume measurement was an amalgamation of multiple cover types. The resultant adjusted default values were 41% for daily cover, 69% for intermediate cover, and 71% for final cover. Direct measurement of landfill methane emissions is preferrable to account for the full range of variables driving landfill emissions, including collection system design and operation. However, applying these updated defaults back into the landfill emission models eliminates underprediction of landfill emissions for the dataset reviewed, and would provide a more accurate estimate of landfill gas emissions where measurements are unavailable.

Characteristics of thin p-MCz Si Microstrip Detector Irradiated upto a mixed fluence of 1017neq./cm2for the FCC

Silicon microstrip detectors can be used for the precise particle tracking in the inner tracking region of the detector used in the future high luminosity collider experiment. In the future experiments, hadron collider provides higher luminosities on the strip detector, and therefore, a detector requires very high radiation hardness. Within CERNRD50collaboration, MCz Si is identified as a prime radiation hard material for the fabrication of the p-Si microstrip detector. In this paper, we have used the experimentally verified four level deep-trap mixed irradiation model for p-MCz Si to investigate the effect of heavy irradiations up to a mixed fluence of 1017n eq./cm2 on the full depletion voltage, leakage current, and charge collection efficiency using SRH and CCE modelling.The changes in the characteristics were evaluated, and effect of the traps on the macroscopic performance of the detectors and possible improvement in the design and semiconductor technology of the p-Mcz silicon microstrip detector.

Batch fabrication of micro-tubular protonic ceramic fuel cells via a phase inversion-based co-spinning/co-sintering technique

Micro-tubular protonic ceramic fuel cells (MT-PCFCs) are prominently advantageous in energy conversion and storage, such as intermediate operating temperature, large volumetric power density, and low sealing requirements. Formation of thin and dense electrolyte film and efficient current collection, particularly from the micro lumen, are the primary challenges for preparing high-performance MT-PCFCs. The present work carries out a one-step fabrication of triple-layer hollow fibers (TLHFs) with anodic current collector/graded anode/electrolyte using BaCe0·7Zr0·1Y0·2O3-δ via the phase-inversion based co-spinning/co-sintering technique. A BaCo0·4Fe0·4Zr0·1Y0·1O3-δ based porous cathode is then applied on the TLHF's outer surface to create a complete fuel cell. The resultant single MT-PCFC yields a peak power density of 601.2 mW cm−2 at 700 °C. Furthermore, an MT-PCFC stack is made by bundling seven TLHFs using the porous cathode. With an effective area exceeding 12 cm2, the MT-PCFC stack generates a power output of 2.5 W at 700 °C. The stability test lasts for 100 h at 600 °C under 100 mA cm−2 and for next 60 h at varied temperatures from 700 to 600 °C under 200 mA cm−2. The inventive design of TLHFs facilitates the scale-up of fuel cells, promoting the development of a large-scale MT-PCFC stack or systems.

Functional ceramic support as an independent catalyst layer for direct liquid fuel solid oxide fuel cells

A porous ceramic support is designed as a multi-functional independent catalyst layer for solid oxide fuel cells (SOFCs) running on liquid hydrocarbon fuel. The layer consists of a highly porous Ce_0.9Ca_0.1O_{2−<i>δ</i>} ceramic backbone and active NiMo catalysts, which could be integrated into the conventional Ni metal containing the anode for internal reforming of the hydrocarbon fuel. Compared to conventional catalyst layers sintered on the anodes, this independent catalyst layer could be simply assembled on top of the anode without additional sintering, thereby avoiding the mismatch of the thermal expansion coefficient between the catalyst layer and the anode and improving stability of a single cell. Moreover, a current collector layer could be inserted between the catalyst and the anode to enhance current collection efficiency and electrochemical performance of the single cell. At 750 ℃, the independent catalyst layer displays high activity towards the catalytic decomposition of methanol, and the single cell could achieve the maximum power density of 400–500 mW·cm⁻² in dry methanol. Furthermore, by employing the independent catalyst layer, the single cell offers additional <i>in-situ</i> catalyst regeneration capability under the methanol operation mode. Feeding 10 mL·min⁻¹ air into an anode channel for 5 min is found to be effective to burn out carbon species in the catalyst layer, which reduces the degradation rate of the cell voltage by orders of magnitude from 2.6 to 0.024 mV·h⁻¹ during the operation of 360 h in dry methanol. The results demonstrate the significance of the independent catalyst layer design for direct internal reforming methanol fuel cells.

Pyro-Phototronic Effect Enhanced Pyramid Structured p-Si/n-ZnO Nanowires Heterojunction Photodetector.

The emergence of nanomaterials has brought about the development of miniature photodetectors into a new stage, and ZnO nanomaterials are currently one of the most popular research objects. Here, the performance of a photodetector consisting of micropyramid structured p-Si/n-ZnO NWs heterojunction constructed by an anisotropic chemical etching and hydrothermal method is optimized by using the pyro-phototronic effect, and the photoresponses of the device to 405 and 648 nm lasers are investigated. The results show that, with the introduction of pyro-phototronic effect, the photoresponsivity Rpyro increases to 208 times that of Rphoto when the wavelength is 405 nm and the optical power density is 0.0693 mW/cm2. Moreover, with the increase of the chopper frequency, the photocurrent increases by more than 3 times, and the photoresponsivity is also increased by a factor of 4.5, making it possible to detect ultrafast pulsed light. In addition, in order to increase the current collection efficiency, a thin film Al layer was deposited as the back electrode on the basis of the device, and the photocurrent and photoresponsivity are significantly improved. Finally, the coupling between the pyro-phototronic effect and the piezo-phototronic effect is analyzed by applying compressive strain to the photodetector. When the compressive strain is -1.02%, the photocurrent decreases by 31.4% and the photoresponsivity decreases by 27.9% due to the opposite direction between laser illumination induced pyroelectric polarization charges and compressive strain induced piezoelectric polarization charges. This work not only demonstrates the great potential of pyro-phototronic effect in enhancing the silicon-based heterojunction photodetectors for high-performance photodetection and ultrafast pulsed light detection but also provides assistance for a better understanding of the coupling mechanism between pyro-phototronic and piezo-phototronic effects.

Surface decoration of ceria nanoparticles as propane/air partial oxidation catalyst integrated in a micro-tubular solid oxide fuel cell

ABSTRACT In this study, a ceria (CeO2) support, synthesized using a hydrothermal method, was decorated with nano-sized Ni-particles using an impregnation method. A micro-tubular solid oxide fuel cell (MTSOFC) was integrated with a corundum tube, in which the Ni-CeO2 (10 wt% Ni) served as the catalyst for partial oxidation (POX). Using propane and air, there was no noticeable deactivation in the MTSOFC over a 48-h period. The maximum power density (MPD) was 0.57 W cm −2 at 700°C using propane and air (12.3 vol% propane), which is 0.01 W cm−2 higher than the cell using 20 vol% of hydrogen (0.56 W cm −2). When using propane and air as fuel and operating at 700°C, MPD values for intermediate and inlet current collector modes were 0.57 and 0.48 W cm−2, respectively. Carbon deposition at the fuel inlet was determined to be the primary cause of low current collection efficiency.

Effect of Cuprous Oxide Nanocubes and Antimony Nanorods on the Performance of Silicon Nanowire-Based Quasi-Solid-State Solar Cell.

Antimony nanorods (SbNRs) anchored to vertically aligned SiNWs serve as cosensitizers and enhance the light absorption of NWs, and their favorably positioned valence band (VB) coupled with their p-type semiconducting nature allows fast hole extraction from SiNWs. Photocorrosion of SiNWs is effectively prevented by a monolayer of N-[3-(trimethoxysilyl)propyl]aniline (TMSPA). Upon assembling a quasi-solid-state solar cell with a SbNRs@TMSPA@SiNW photoanode, a triiodide-iodide (I3 -/I-) redox couple-based gel encompassing dispersed p-type cuprous oxide nanocubes (Cu2O NCs) as the hole transport material. and an electrocatalytic NiO as the counter electrode, a power conversion efficiency (PCE) of 4.7% (under 1 sun) is achieved, which is greater by 177% relative to an analogous cell devoid of the Cu2O NCs and SbNRs. SbNRs at the photoanode maximize charge separation and suppress electron-hole and electron-I3 - recombination at the photoanode/electrolyte interface, thereby improving the overall current collection efficiency. Concurrently, the Cu2O NCs facilitate hole scavenging from SbNRs or SiNWs and relay them rapidly to the I- ions in the electrolyte. Optically transparent and mesoporous NiO with a VB conducive to accepting electrons from FTO permits abundant interaction with I3 - ions. The high PCE is a cumulative outcome of the synergistic attributes of SbNRs, Cu2O NCs, and NiO. The SbNRs@TMSPA@SiNWs/Cu2O-gel/NiO solar cell also exhibits a noteworthy operational stability, for it endures 500 h of continuous 1 sun illumination accompanied by an ∼24.4% drop in its PCE. The solar cell architecture in view of the judiciously chosen components with favorable energy level offsets, semiconducting/photoactive properties, and remarkable stability opens up pathways to adapt these materials to other solar cells as well.

Influence of wire spacing and plate spacing on electrostatic precipitation of nanoparticles: An approach involving electrostatic shielding and diffusion charging

Electrostatic precipitation is a process widely used as gas cleaning device, to removal particles from gas flows. However, in a conventional and well-sized precipitator, the collection efficiency decreases for ultrafine particles, making it difficult to employ this equipment for controlling nanoparticle pollution. This paper investigates the influence of plate spacing (4 and 6.5 cm) and wire spacing (4, 6, and 12 cm) on the electric current and nanoparticle collection efficiency, considering the effect of diffusion charging and electrostatic shielding. Two laboratory-scale dry wire-plate electrostatic precipitators with different plate spacings were tested for the collection of nanoparticles (6.15–241.4 nm) at three air velocities (1.9, 2.9, and 3.9 cm/s). The results demonstrated the effectiveness of the equipment in removing nanoparticles (99.9%) under the highest electric fields. Higher values of the wire spacing led to increases in the current and the collection efficiency. This was associated with reduced electrostatic shielding, which is more evident in smaller ducts with a higher density of field lines. It is expected that the findings should improve knowledge on electrostatic precipitation of nanoparticles, enabling optimization of collection efficiency by considering the effects of geometric parameters.

Development of a Model of Current Distribution in the Overhead Contact Lines for an Innovative de-Icing System

Icing on the overhead contact line exclude the possibility of efficient current collection from the overhead contact line. The effects of icing can result in losses for carriers due to delay or cancellation of trains and also cases of damage to the traction infrastructure and pantographs. The existing methods of de-icing the traction network (mechanical, chemical and electrical) are currently ineffective. Therefore, it is necessary to develop a new electrical method that takes into account the detailed current fl ow in the over-head contact line. This article presents a model for calculating the current fl ow in the overhead contact line and the resistances of droppers, suspension elements, and distance holders measured on the basis of actual measurements. Keywords: simulation model, de-icing of the contact line, current flow in the contact line

Fabrication of a Hydrogenated Amorphous Silicon Detector in 3-D Geometry and Preliminary Test on Planar Prototypes

Hydrogenated amorphous silicon (a-Si:H) can be produced by plasma-enhanced chemical vapor deposition (PECVD) of SiH4 (silane) mixed with hydrogen. The resulting material shows outstanding radiation hardness properties and can be deposited on a wide variety of substrates. Devices employing a-Si:H technologies have been used to detect many different kinds of radiation, namely, minimum ionizing particles (MIPs), X-rays, neutrons, and ions, as well as low-energy protons and alphas. However, the detection of MIPs using planar a-Si:H diodes has proven difficult due to their unsatisfactory S/N ratio arising from a combination of high leakage current, high capacitance, and limited charge collection efficiency (50% at best for a 30 µm planar diode). To overcome these limitations, the 3D-SiAm collaboration proposes employing a 3D detector geometry. The use of vertical electrodes allows for a small collection distance to be maintained while preserving a large detector thickness for charge generation. The depletion voltage in this configuration can be kept below 400 V with a consequent reduction in the leakage current. In this paper, following a detailed description of the fabrication process, the results of the tests performed on the planar p-i-n structures made with ion implantation of the dopants and with carrier selective contacts are illustrated.

On the nature of photosensitivity gain in Ga2O3 Schottky diode detectors: Effects of hole trapping by deep acceptors

Lightly n-type doped Ga2O3 layers grown by Halide Vapor Phase Epitaxy (HVPE) on bulk n+-Ga2O3 substrates were subjected to irradiation with fast reactor neutrons, 20 MeV protons, or treatment in high ion density Ar plasma. These treatments lead to a marked increase in the concentration of deep acceptors in the lower half of the bandgap. These acceptors have optical ionization thresholds near 2.3 eV and 3.1 eV. There is a simultaneous strong enhancement of the photocurrent of Schottky diodes fabricated on these layers in the UV spectral range, and a large increase in the Electron Beam Induced Current (EBIC) collection efficiency. The gain in photocurrent at −10 V reached 18 times for neutron and proton irradiated samples, and 104 times for the plasma treated samples. Similar increases in gain were observed in the EBIC current collection efficiency for beam energy 4 keV. With such beam energy, the electron–hole pairs are generated well within the space charge region. The results are explained by assuming that the capture of photoinduced or electron-beam-induced holes by the deep acceptors gives rise to a decrease in the effective Schottky barrier height and an increase of the electron current flow that is responsible for the observed high gain. The reported observation could form a basis for radical improvement of photosensitivity of Ga2O3-based solar-blind photodetectors. However, the photocurrent build-up and decay times in this mechanism are inherently long, on the order of some seconds.

Theory-Driven Design of Electrocatalysts for the Two-Electron Oxygen Reduction Reaction Based on Dispersed Metal Phthalocyanines

Theory-Driven Design of Electrocatalysts for the Two-Electron Oxygen Reduction Reaction Based on Dispersed Metal Phthalocyanines

Analysis of current collection in micro-tubular solid oxide fuel cells: An empirical and mathematical modelling approach for minimised ohmic polarisation

Data from electrochemical impedance spectroscopy (EIS) of a 152 mm long, 6.8 mm outer diameter (OD) segmented-in-series micro-tubular solid oxide fuel cell (μT-SOFC) coupled with equivalent circuit modelling (ECM) support a circuit model and a continuum resistance path model to investigate the ohmic polarisation and current distribution for various current collector configurations on a micro-tube. Minimising the characteristically long axial current conduction pathways of μT-SOFCs is critical to maximise cell performance, particularly of cells more than a few centimetres long. Optimal positioning of a single current collector minimises the performance losses from the electrode. Multiple current collector terminals increase cell performance over a single terminal, but positioning must still be optimised. Sizing of the current collector terminal is critical to limit the loss of active area of the cathode. A trade-off between terminal sizing/spacing and loss of active area can lead to sub-optimal current collection. The models are generalised for all possible current collector configurations. We identify simple criteria to determine the maximum current collection efficiency of single and multiple anode current collectors for a range of cell geometries. The design tool allows early consideration to cell sizing as a function of anode current collection during cell and stack development.

The Development of Current Collection in Micro-Tubular Solid Oxide Fuel Cells—A Review

Micro-tubular solid oxide fuel cells (µT-SOFCs) are suited to a broad range of applications with power demands ranging from a few watts to several hundred watts. µT-SOFCs possess inherently favourable characteristics over alternate configurations such as high thermo-mechanical stability, high volumetric power density and rapid start-up times, lending them particular value for use in portable applications. Efficient current collection and interconnection constitute a bottleneck in the progression of the technology. The development of current collector designs and configuration reported in the literature since the inception of the technology are the focus of this study.

Corrigendum: Corrigendum: A Defect‐rich N, P Co‐doped Carbon Foam as Efficient Electrocatalyst toward Oxygen Reduction Reaction

This is a Corrigendum for the article entitled “A Defect-rich N, P Co-doped Carbon Foam as Efficient Electrocatalyst toward Oxygen Reduction Reaction”, published in ChemCatChem 2020, 12, 4105-4111, DOI: 10.1002/cctc.202000363. We regret to inform you that part of Experimental Section was not presented correctly. The authors requested corrections to this paper at the proof stage, however the corrections to were not applied. The Editorial office apologizes for this oversight. Please see the following as the corrected version: The electron number (n) transferred per oxygen molecule and kinetic current (jk) for ORR procedure can be extracted from the Koutechy-Levich equation:[46] where j is measured current, jd represents the diffusion-limiting current, jk is the kinetic current and ω is the rotating rate. B is determined from the slope of Koutechy-Levich (K−L) plots according to the Levich equation as given below:[46] where n represents the transferred electron number per oxygen molecule. F is the Faraday constant (F=96485 C mol−1), DO2 is the diffusion coefficient of O2 in 0.1 M KOH (DO2=1.9×10−5 cm2 s−1). υ is the kinetic viscosity (υ=0.01 cm2 s−1). CO2 is the bulk concentration of O2 (CO2=1.2×10−6 mol cm−3). The constant 0.2 is adopted when the rotation speed is expressed in rpm. (CO2=1.2×10−6 mol cm−3). The constant 0.2 is adopted when the rotation speed is expressed in rpm. The yield and n (the number of electrons transferred during ORR) were estimated by the followed equations:[47] where Ir is ring current, Id is disk current and N is current collection efficiency of the Pt ring. N was determined to be 0.40.[18]

Modeling radiation damage in the pixel sensors of the ATLAS detector

As the integrated luminosity delivered by the Large Hadron Collider increases, radiation damage effects are increasingly apparent in the response of the vertex detectors of the experiments. In this contribution, measurements of these effects are discussed for the Pixel Detector of the ATLAS experiment, which by the end of LHC Run 2 has received a fluence of up to 1015neqcm−2. Measurements of leakage current, Lorentz angle, and charge collection efficiency are discussed and compared to predictions from the Hamburg radiation damage model, TCAD based calculations, and a detailed simulation of the pixel sensor response which accounts also for the modifications to the electric field and charge collection efficiency induced by the radiation damage.

“Paper Dye-Sensitized Solar Cell” Based on Carbon-Nanotube-Composite Papers

We propose a paper solar cell based on carbon nanotube (CNT)-composite papers. To fabricate this cell, we use dye-sensitized solar cells (DSCs) for generating power through the redox reaction of dyes in conjunction with CNT-composite papers, which are composite materials containing CNTs and pulp (raw paper material) that can be fabricated easily by using a method based on the Japanese washi papermaking technique. The demand for CNT applications is expected to increase due to their high conductivity and metallic or semiconducting characteristics. This CNT-composite paper can also have metallic or semiconducting characteristics based on the contained CNTs in the composite paper. We previously fabricated a DSC that generates electricity by using CNT-composite papers stacked in a typical DSC structure. However, the conversion efficiency of this DSC was just 0.188%, which is not practical. To overcome this low power generation issue, we tried improving the DSC structure by applying electrodes to the CNT-composite papers in grid patterns for efficient current collection and applying an optimally mixed dye for efficient electron excitation. Results showed that the conversion efficiency improved to 0.58%. Moreover, we demonstrated that using a mixed dye can improve the conversion efficiency of the paper DSC. We expect these types of CNT-composite papers to be used as material for new DSCs.

Nanopiezoelectric Devices for Energy Generation Based on ZnO Nanorods/Flexible-Conjugated Copolymer Hybrids Using All Wet-Coating Processes.

In this study, nanopiezoelectric devices based on ZnO nanorod array/conducting polymers are fabricated for wearable power generation application. To replace the inorganic rigid indium-tin oxide (ITO) conducting coating commonly used in the nanogenerator devices, a series of flexible polyaniline-based conducting copolymers underlying the perpendicularly-oriented ZnO nanorod arrays has been synthesized with improved electric conductivity by the copolymerization of aniline and 3,4-ethylenedioxythiophene (EDOT) monomers in order to optimize the piezoelectric current collection efficiency of the devices. It is found that significantly higher conductivity can be obtained by small addition of EDOT monomer into aniline monomer solution using an in-situ oxidative polymerization method for the synthesis of the copolymer coatings. The highest conductivity of aniline-rich copolymer is 65 S/cm, which is 2.5 times higher than that for homopolymer polyaniline coating. Subsequently, perpendicularly-oriented ZnO nanorod arrays are fabricated on the polyaniline-based copolymer substrates via a ZnO nanoparticle seeded hydrothermal fabrication process. The surface morphology, crystallinity, orientation, and crystal size of the synthesized ZnO nanorod arrays are fully examined with various synthesis parameters for copolymer coatings with different monomer compositions. It is found that piezoelectric current generated from the devices is at least five times better for the device with improved electric conductivity of the copolymer and the dense formation of ZnO nanorod arrays on the coating. Therefore, these results demonstrate the advantage of using flexible π-conjugated copolymer films with enhanced conductivity to further improve piezoelectric performance for future wearable energy harvesting application based on all wet chemical coating processes.