Charge Collection Research Articles

Enhancing fine particle removal by electrostatic precipitation from flue gas with a high PM concentration: Effect of various electrode configurations

Particle pollution has hazardous effects on air quality and human health, especially fine particle. However, the highly efficient removal of fine particles is an unsolved problem in electrostatic precipitators (ESPs). In this study, a transparent ESP was designed to investigate the effect of fine particles on the corona discharge performance and the role of ionic wind in particle migration. And five types of typical discharge electrodes were applied. The results showed that the presence of fine particles could weaken the corona current produced by electrode discharge. Among these electrodes, the spike electrode can reduce the adverse effect of the particle space charge. The maximum ionic wind velocity around the electrode tips and within the near-plate region could reached 5.67 m/s and 5.00 m/s under an applied voltage of 30 kV, respectively. Combining the effects of corona discharge and ionic wind, the collection efficiencies of fine particles decreased in the following order: spike electrode (medium needle) > spike electrode (longest needle) > arista electrode > spike electrode (shortest needle) > sawtooth electrode. In general, spike electrode discharge has better performance for particle charging and particle collection efficiency and is suitable for fine particle removal in ESPs. In addition, electrode configuration/arrangement optimization methods were proposed to enhance fine particle removal in ESPs.

Diode Equation for Sandwich-Type Thin-Film Photovoltaic Devices Limited by Bimolecular Recombination

Analytical diode models that relate the current to key material parameters are invaluable for understanding the device physics in photovoltaic (PV) devices. However, a diode model that accurately describes the current in thin-film PVs based on low-mobility semiconductors (including organic solar cells) limited by bimolecular recombination has been lacking. Previous models neglect effects of injected charge carriers, which are the predominant source for bimolecular recombination in thin-film PV systems with Ohmic contacts. In this work, we derive a unified diode equation for thin-film PVs based on undoped semiconductors limited by bimolecular recombination. Based on a regional approximation approach, we derive an analytical model for the current accounting for the interplay between charge-carrier extraction, injection, and bimolecular recombination. The analytical model is validated by numerical simulations and tested experimentally on organic solar cells. Our findings provide key insights into the mechanisms driving and limiting charge collection, and ultimately the power-conversion efficiency, in low-mobility PV devices. The presented framework is material agnostic and generally applicable to sandwich-type thin-film PV devices, including photodiodes and indoor light-harvesting cells. Published by the American Physical Society 2024

Enhancing open-circuit voltage and suppression of energy loss in ternary organic photovoltaics utilizing carbazole/bicarbazole-based guest donors

The third component in binary organic photovoltaics (OPV) plays a crucial role in finely adjusting light absorption, reducing energy loss, and optimizing the blend morphology. We introduce four A-π-D-π-A type small molecules as guest-donor materials, employing easily accessible starting materials. These molecules incorporate carbazole or bicarbazole as the core structure, along with pyran-4-ylidene-malononitrile or pyran-4-ylidene-indenedione derivatives as electron-accepting end groups. We explore the miscibility of guest donors with Y6 and analyze the energy loss in corresponding OPVs. Tapping mode atomic force microscopy and grazing incidence wide-angle X-ray (GIWAX) scattering analysis confirm that the twisted configuration of the guest donor CY-3 disperses effectively into the Y6 domain, promoting the formation of an alloy-like structure and maximizing the energy gap (Egap) of OPVs. CY-3 improves the molecular packing of Y6 in ternary blend and optimizes the blend morphology, leading to the minimum non-radiative energy recombination (ΔEnon-rad) and energy loss (Eloss) in the corresponding ternary OPV which exhibits an optimized Voc of (0.891 ± 0.006 V). The optimized blend morphology also, suppresses bimolecular and trap-assisted recombination, and improves charge collection. Ternary devices employing PM6/PY-IT, PM6/Y18, PM6/L8-BO, and PM6/BTP-eC9 demonstrate significant improvements in their Voc. Particularly remarkable is the attainment of the highest PCE of 17.18 % in the OPV based on PM6/BTP-eC9 with the incorporation of CY-3.

High performance hydrovoltaic devices based on asymmetrical electrode design

As a promising method for energy harvesting, water evaporation can generate electrical energy without additional mechanical energy input. In the evaporation power generation unit based on the principle of flow potential, the low charge collection efficiency is the key factor limiting the energy output, which limits the practical application of water evaporation equipment. Based on the principle of evaporation potential, an asymmetric sandwiched hydrovoltaic device based on metallic aluminum plate and carbon cloth electrodes is designed, which not only matches the electrode, but also reduces the carrier migration route and realizes fast charge transfer and collection. The device achieves an open-circuit voltage (Voc) of 730 mV and a short-circuit current density (Jsc) of 558 μA cm−2, capable of producing output power density exceeding 61.7 μW cm−2. Micro-nano electronic devices with low power consumption can be powered by integration of multiple devices. This study proposes a strategy for clean energy collection based on water evaporation.

Efficient and economically affordable TiO2 nanotube-based ternary photocatalysts for CO2 conversion boosted by NiO nanoparticles and carbon quantum dots

Photocatalytic CO2 conversion, in general, requires the incorporation of expensive and noble materials to achieve a highly efficient conversion rate. Herein, the TNT/NiO/CQD ternary nanocomposites without any expensive materials and material modification are fabricated for the demonstration of efficient and economically affordable photocatalytic CO2 conversion, to our best knowledge, for the first time. The TNT-based ternary photocatalysts are successfully prepared by a simple anodization and immersion process. The TNT/NiO/CQD ternary nanocomposites produce 1.47 μmol·cm-2·h-1 (≈c.a. 2834 μmol·g-1·h-1) of CH4 as the sole product under AM 1.5 illumination. This is five times higher performance than that of bare TNT and the performance is comparable to that of any other TiO2-based unitary, binary, or ternary photocatalysts. This highly enhanced performance results from effective junction formation between TNT and NiO NP, and the dual role of CQDs as a light absorber and charge transporter/collector in the system. The formation of Z-scheme at the TNT/NiO interface leads to efficient charge transfer via a TiO2/NiO bond. The light absorption of the photocatalysts is enhanced and extended by decorated CQDs due to their small band gap. The charge transfer and collection are further improved by charge depletion at the TNT/CQD interface and the charge transfer at the NiO/CQD interface. This work provides a possible model for the realization of efficient and economically affordable photocatalytic CO2 conversion.

Development and Fabrication of Microdosimeter Arrays Based on Single‐Crystal Diamond Schottky Diodes

The interest in microdosimetry is growing thanks to the advancement in microdosimetric technologies, improving detector performance and reliability. Herein, the fabrication and characterization of a novel diamond‐based microdosimeter are proposed. The microdosimeter consists of an array of single‐crystal diamond Schottky diodes about 1.5 μm thick connected in parallel. The detector prototypes are characterized using the ion beam‐induced charge technique, employing a 6 MeV carbon ions microbeam. Despite a good overall response, the first prototypes are affected by the “bridge effect”: a charge collection beneath the metallic bridges connecting the sensitive volumes (SVs), which alters the energy deposition spectrum. To mitigate the bridge effect, different technological solutions are explored: the selective growth of intrinsic diamond layers and the use of an insulating material such as photoresist. These second prototypes reveal a good SV spatial definition without any charge collection from the bridges and a good response homogeneity within the SVs ranging between 3% and 5% full‐width‐half‐maximum among the different prototypes. While the cell‐like thickness and lateral dimensions of SVs make the diamond microdosimeter array ideal for radiobiological applications, its array configuration can make it highly versatile to perform under different fluence rate conditions in particle therapy.

Controlling vertical phase separation and crystallization via solvent synergy strategy to empower layer-by-layer processed organic solar cells

The novel sequential layer-by-layer (LbL) processed organic solar cells (OSCs) have attracted continuous attention due to their advantages of ideal vertical phase separation, efficient charge transport and collection, and potentiality for large-scale production from laboratory to factory. Herein, a solvent synergy strategy is put forward to control morphology, crystallization and vertical phase distribution of blend films, which means the donor PM6 and acceptor Y6 treated by high/low boiling point solvents are fabricated using LbL solution process, respectively. Based on device with a configuration of ITO/ZnO/PM6:Y6/MoO3/Ag, OSCs derived from the solvent synergy strategy can obtain a remarkable power conversion efficiency (PCE) up to 15.03%, which is comparable to that of the bulk heterojunction devices prepared by conventional one-step solution method. This impressive result provides an insightful understanding of phase segregation and crystalllization in LbL processed OSCs assisted by the solvent synergy strategy. It lays the foundation for fabrication and optimization of high-performance, large-area OSCs in industrial production.

X-ray characterization of a bulk resistive MICROMEGAS operating at low gas pressure

In the last decades, interest has grown in the development of detectors that can accurately measure energy and track of low-energy (1–100 keV) charged particles. In this paper we present our effort to construct a resistive MICROMEGAS detector with a wide amplification gap (192μm), to achieve high gain with a low discharge probability, even when operating with a low-pressure gas down to 50mbar. The detector response (gain, energy resolution, relative primary charge collection efficiency) to X-rays from a 55Fe source was measured under different operating conditions of amplification and drift fields, gas pressure and gas mixture composition. The results obtained and their temporal stability demonstrate that the detector can be used for the measurement of low-energy radiation with good energy resolution.

An MBene Modulating the Buried SnO2/Perovskite Interface in Perovskite Solar Cells

AbstractThe interface of perovskite solar cells (PSCs) plays an important role in transferring and collecting charges. Interface defects are important factors affecting the efficiency and stability of PSCs. Here, the buried interface between SnO2 and the perovskite layer is bridged by two‐dimensional (2D) MBene, which improves charge transfer. MBene can deposit additional electrons on the surface of SnO2, passivate its surface defects and facilitate the charge collection. Moreover, the dipole moment formed at the interface increases the electron transfer ability in the PSCs. MBene also regulates the growth of perovskite crystals, improves the quality of perovskite films, and reduces its grain boundary defects. As a result, PSCs based on FA0.2MA0.8PbI3 and (FAPbI3)0.95(MAPbBr3)0.05 get the enhanced efficiencies of 22.34 % and 24.32 % with negligible hysteresis. Furthermore, the optimized device exhibits better stability. This work opens up the application of MBene materials in PSCs, reveals a deeper understanding of the mechanism behind using 2D materials as an interface modification layer, and shows opportunities for using MBene as potential material in photoelectric devices.

Rapid Surface Reconstruction of In2S3 Photoanode via Flame Treatment for Enhanced Photoelectrochemical Performance.

Surface reconstruction, reorganizing the surface atoms or structure, is a promising strategy to manipulate materials' electrical, electrochemical, and surface catalytic properties. Herein, a rapid surface reconstruction of indium sulfide (In2S3) is demonstrated via a high-temperature flame treatment to improve its charge collection properties. The flame process selectively transforms the In2S3 surface into a diffusionless In2O3 layer with high crystallinity. Additionally, it controllably generates bulk sulfur vacancies within a few seconds, leading to surface-reconstructed In2S3 (sr-In2S3). When using those sr-In2S3 as photoanode for photoelectrochemical water splitting devices, these dual functions of surface In2O3/bulk In2S3 reduce the charge recombination in the surface and bulk region, thus improving photocurrent density and stability. With optimized surface reconstruction, the sr-In2S3 photoanode demonstrates a significant photocurrent density of 8.5mA cm-2 at 1.23V versus a reversible hydrogen electrode (RHE), marking a 2.5-fold increase compared to pristine In2S3 (3.5mA cm-2). More importantly, the sr-In2S3 photoanode exhibits an impressive photocurrent density of 7.3mA cm-2 at 0.6V versus RHE for iodide oxidation reaction. A practical and scalable surface reconstruction is also showcased via flame treatment. This work provides new insights for surface reconstruction engineering in sulfide-based semiconductors, making a breakthrough in developing efficient solar-fuel energy devices.

Simulation and efficiency improvement of perovskite solar cells using optimized carbon nanotube charge collector and molybdenum trioxide layer

Simulation and efficiency improvement of perovskite solar cells using optimized carbon nanotube charge collector and molybdenum trioxide layer

A solar diffusion-absorption refrigeration system for off-grid cold-chain provision, Part II: System simulation and assessment of performance

The diffusion-absorption refrigerator (DAR) is a cooling technology that can be driven entirely by thermal energy. With solar-thermal collectors as the heat source, this technology can provide a zero-emissions solution for essential cold-chain provision in the world’s poorest regions. In the accompanying paper, a system model of a solar-driven DAR system was developed for simulating operation under variable solar conditions. In Part II of this study, we apply this model to assess the predicted performance of the system in its intended application: for on-farm refrigeration of harvested crops in rural India. The roles of the working-fluid charge pressure and collector array area for maximum cooling are investigated. A charge pressure of 16 bar is found to be optimal for ambient conditions during the October harvest season in Ahmedabad, with a collector-array area of 1.5 m2 found to be most appropriate for the nominal 70 W cooling-capacity system. However, the time taken to reach the required solar collector temperature for bubble pump activation results in a daily operating period of less than 5 h and a predicted overall solar-to-cooling efficiency of less than 1%. To address these limitations, modifications to various components are considered based on simple assumptions for improving performance.

Picosecond laser capture microdissection based on edge catapulting combined with dielectrophoretic force.

The spatial omics information analysis of heterogeneous cells or cell populations is of great importance for biomedical research. Herein, we proposed a picosecond laser capture microdissection boosted by edge catapulting combined with dielectrophoretic force (ps-LMED) that enables fast and non-invasive acquisition of uncontaminated cells and cell populations for downstream molecular assays. The target cells were positioned under a microscope and separated by a focused picosecond pulsed laser. The system employed the plasma expansion force during cutting to lift the target and captured it under dielectrophoretic force from the charged collection cap eventually. The principle of our system has been validated by both theoretical analysis and practical experiments. The results indicated that our system can collect samples ranging from a single cell with a diameter of a few microns to large tissues with a volume of 532,500 µm3 at the moment finishing the cutting, without further operations. The cutting experiments of living cells and ribonucleic acid (RNA) and protein omics analysis results of collected targets demonstrated the advantage of non-destructiveness to the samples and feasibility in omics applications.

Research on the Expansion Application of Electronic Toll Collection System

Electronic Toll Collection (ETC) system is an important part of modern intelligent transport system, which plays an important role in intelligent car parks and congestion charging. Electronic Toll Collection (ETC) system includes automatic vehicle identification system and electronic billing system. The automatic vehicle identification system includes three parts: automatic vehicle identification (AVI), automatic vehicle model identification (AVC) and inspection system (ES).The application of ETC in intelligent car parks and congestion charging also includes automatic vehicle identification system (automatic vehicle identification, automatic vehicle model identification and inspection system) and electronic billing system. In intelligent car parks, ETC technology achieves fast and accurate automatic toll payment by automatically identifying the ETC tags carried by vehicles, which greatly improves the efficiency of car parks and reduces the queuing and waiting time due to manual toll collection. In terms of congestion charging, ETC technology provides an effective means to implement congestion charge collection. By setting up ETC toll lanes in core urban areas or busy road sections, the system can automatically record the information of the vehicles passing through and carry out toll settlement, thus realising dynamic toll collection according to the degree of congestion and the frequency of vehicle use. This congestion charging strategy aims to regulate urban traffic flow through economic means, alleviate traffic congestion and promote the sustainable development of urban transport. Although China's theoretical research on congestion charging, has been relatively mature, but affected by a variety of factors, no city has yet to start the implementation of congestion charging, the lack of experience in practice. Singapore will not stop the car charging system (ETC) technology successfully applied to urban congestion charging and intelligent car parks, ETC system in intelligent car parks and congestion charging application, help to promote the development of urban transport to a more intelligent, green direction. China can learn from the successful experience of foreign countries and apply it to its own intelligent car parks and congestion charging. This paper introduces the basic principle of ETC, discusses the research progress of ETC in terms of technical characteristics, and analyses the application scenarios of ETC in intelligent car parks and congestion charging. By examining the opportunities offered by Electronic Toll Collection (ETC) systems in smart car parks and congestion pricing, this study aims to delve into the transformative impacts of Electronic Toll Collection (ETC) systems on intelligent mobility and contribute to the sustainable development of intelligent mobility.

A multi-electrode two-dimensional position sensitive diamond detector

In multi-electrode devices, charge pulses at all the electrodes are induced concurrently by the motion of the excess charge carriers generated by a single ion. This charge-sharing effect is such that the pulse amplitude at each sensitive electrode depends on the device geometry, its overall electrostatic configuration, and the charge transport properties of the detecting material. Therefore, the cross-analysis of the charge pulses induced at each electrode offers implicit information on the position of the ion impact. In this work, we investigate the two-dimensional position sensitivity of a diamond detector fabricated by deep ion beam lithography. By exploiting the ion beam induced charge technique, the device was exposed to a 2 MeV Li+ ion micro-beam to map the spatial dependence of the charge collection efficiency (CCE) on the nominal micro-beam scanning position. The combination of the CCE maps revealed a two-dimensional position sensitivity of the device with micrometric resolution at the center of the active region.

Heavy ions and alpha particles irradiation impact on III-V broken-gap gate-all-around TFET

This report deals with the impact of radiation on III-V and Si gate-all-around tunnel field effect transistors (GAA TFET). The highly energetic particles (HEPs) such as heavy ions and alpha particles are allowed to strike the device at several locations along the channel to determine the sensitive location of the device. Once the sensitive location is determined, then the device is irradiated to different energies of heavy ions and alpha particles. Further, to get a proximate match as a practically exposed device, the device has been irradiated to several incident angles. Before analyzing the device's behaviour, the models used for the analysis are calibrated with the transfer characteristics of an experimentally published report on III-V GAA TFET. Thereafter, analysis of charge collection, transient current, hole generation in the channel, and different incident angles are analyzed. Finally, it is concluded that III-V GAA TFET shows better immunity towards different incident angles under a radiation environment when compared to Si GAA TFET.

Increasing terminal alkyl chain length for a better small molecule organic solar cell donor

Optimizing the alkyl chains within a terminal group is considered to be a highly effective approach for boosting the power conversion efficiency (PCE) of all small-molecule organic solar cells (ASM-OSCs). In this study, we focus on designing and synthesizing small molecular (SM) donor compounds with different end-group alkyl chain lengths to study their impact on OSC performance. Under optimized conditions, OSC devices based on BTR-Cl-C8:Y6 demonstrate higher PCE of 14.43 % compared to those based on BTR-Cl:Y6. Moreover, BTR-Cl-C8 exhibits reduced levels of bimolecular recombination and trap-assisted recombination, enhanced capability for exciton dissociation and charge collection, and extended carrier lifetimes. These results highlight the significance of molecular design strategies in optimizing OSC performance and offer valuable insights for the development of efficient and stable ASM-OSCs.

Novel layout technique for single-event transient mitigation by the groove structure

Based on the damage mechanism of single-event transient (SET) in a MOS device, a new irradiated reinforcement uniaxial strained Si Nano NMOSFET device is further proposed, and the new structure device has no effect on the electrical properties of its original structure. Moreover, the new reinforced device of groove structure can efficiently reduce not only charge collection but also SET pulse widths (WSET). Compared with the conventional NMOS and drain-wall structure, we find that the proposed novel layout technique can provide the best benefit of SET mitigation with a small sacrifice in the effective area. Therefore, the successful development of the research results will play a positive role in promoting the theoretical and technological progress of high-performance radiation-resistant core electronic components and lay a foundation and create conditions for their application in space radiation and nuclear radiation.

Demonstration of event position reconstruction based on diffusion in the NEXT-white detector

Noble element time projection chambers are a leading technology for rare event detection in physics, such as for dark matter and neutrinoless double beta decay searches. Time projection chambers typically assign event position in the drift direction using the relative timing of prompt scintillation and delayed charge collection signals, allowing for reconstruction of an absolute position in the drift direction. In this paper, alternate methods for assigning event drift distance via quantification of electron diffusion in a pure high pressure xenon gas time projection chamber are explored. Data from the NEXT-White detector demonstrate the ability to achieve good position assignment accuracy for both high- and low-energy events. Using point-like energy deposits from 83m\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{83\ extrm{m}}$$\\end{document}Kr calibration electron captures (E∼45\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$E\\sim 45$$\\end{document} keV), the position of origin of low-energy events is determined to 2 cm precision with bias <1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$< 1~$$\\end{document}mm. A convolutional neural network approach is then used to quantify diffusion for longer tracks (E≥1.5\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$E\\ge ~1.5$$\\end{document} MeV), from radiogenic electrons, yielding a precision of 3 cm on the event barycenter. The precision achieved with these methods indicates the feasibility energy calibrations of better than 1% FWHM at Qββ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$_{\\beta \\beta }$$\\end{document} in pure xenon, as well as the potential for event fiducialization in large future detectors using an alternate method that does not rely on primary scintillation.

Engineering Charge Density Waves by Stackingtronics in Tantalum Disulfide.

In the realm of condensed matter physics and materials science, charge density waves (CDWs) have emerged as a captivating way to modulate correlated electronic phases and electron oscillations in quantum materials. However, collectively and efficiently tuning CDW order is a formidable challenge. Herein, we introduced a novel way to modulate the CDW order in 1T-TaS2 via stacking engineering. By introducing shear strain during the electrochemical exfoliation, the thermodynamically stable AA-stacked TaS2 consecutively transform into metastable ABC stacking, resulting in unique 3a × 1a CDW order. By decoupling atom coordinates, we atomically deciphered the 3D subtle structural variations in trilayer samples. As suggested by density functional theory (DFT) calculations, the origin of CDWs is presumably due to collective excitations and charge modulation. Therefore, our works shed light on a new avenue to collectively modulate the CDW order via stackingtronics and unveiled novel mechanisms for triggering CDW formation via charge modulation.