Electrical Performance Research Articles

An overview on building-integrated photovoltaics: technological solutions, modeling, and control

The advancement of renewable and sustainable energy generation technologies has been driven by environment-related issues, energy independence, and high costs of fossil fuels. Building-integrated photovoltaic systems have been demonstrated to be a viable technology for the generation of renewable power, with the potential to assist buildings in meeting their energy demands. This work reviews the current status of novel PV technologies, including bifacial solar cells and semi-transparent solar cells. This review discusses the various constructions of PV technologies, recent advances in these products, the influence of key design factors on electrical and thermal performance, and their potential in the design of energy-efficient smart buildings. The attention is focused on bifacial and semi-transparent PV systems, given the high level of interest of the scientific community in their current and potential applications.Focus is also devoted to the analysis of the electrical, optical, and thermal modeling procedures developed for sizing, designing, and integrating photovoltaics into larger building simulations. The development of these models has a positive impact on the implementation of next-generation smart buildings. The latest innovative developments and key issues in the application of bifacial PV solutions in buildings are also summarized and analyzed. Special attention is paid to rear side electrical performance, which can be evaluated by means of illuminance/optical backside modeling. Finally, energy management and control of PV-equipped buildings via both model-based and data-driven approaches are discussed, as well as the integration of electric storage systems in a multi-building context.

Mechanical simulation and electrical performance analysis of high current connectors

Abstract Automotive high-current connectors are one of the key components in new energy vehicles, used for transmitting high currents within the vehicle. However, vibration is unavoidable during the actual operation of connectors. This vibration directly affects the contact pressure between the connector’s contact points, thereby influencing the electrical contact performance of the connector. This paper simplifies the contact components of the electrical connector using a cantilever beam model and conducts theoretical calculations of the contact pressure. Utilizing Ansys Workbench simulation software, the study investigates the contact pressure of the electrical connector under static and various sinusoidal vibration conditions, followed by sinusoidal frequency sweep vibration experiments. The research findings indicate that under vibration conditions, the contact pressure is lower than that under static conditions, and the electrical resistance fluctuates during the vibration process.

Shape Matters: Understanding the Effect of Electrode Geometry on Cell Resistance and Chemo-Mechanical Stress

Rechargeable batteries that incorporate shaped three-dimensional electrodes have been shown to have increased power and energy densities when compared to a conventional geometry, i.e. a planar cathode and anode that sandwich an electrolyte. Electrodes can be shaped to enable a higher active material loading, while keeping ion transport distances small. However, the relationship between electrical and mechanical performance of shaped electrodes remains poorly understood. Many electrode designs have been explored, where the electrodes are individually shaped or intertwined, and advances in manufacturing and shape/topology optimization have made such designs a reality. Here, we explore sinusoidal half cells and interdigitated full cells. First, we use a simple electrostatics model to understand the cell resistance as a function of shape. We focus on low-temperature conditions, where the electrolyte conductivity decreases relative to that of the electrode; here, LiPF6 EC:DMC electrolyte and MnO2 electrode are considered. Next, we use a chemo-mechanics model to examine the stress that arises due to intercalation-driven volume expansion. We show that shaped electrodes provide a significant reduction in resistance in low-temperature conditions, however, they exhibit unfavorable stress concentrations. Overall, we find that the fully interdigitated electrodes may provide the best balance with respect to this resistance-stress trade-off.

Investigating the multiferroic properties within triphasic systems to comprehend the mechanisms of water splitting

In the present study, a triphasic-based system was prepared using constituents such as Lanthanum Calcium Manganite (LCM), Cobalt Ferrite (CF), and Barium Titanate (BT) in different proportions. The composition (1-x)LCM: x(0.7CF-0.3BT), where x = 0, 0.1, 0.2, 0.3, and 1, was employed to produce the triphasic system-based materials using a solid-state reaction technique. X-ray diffraction results confirmed the development of the triphasic phase in the composites through the JCPDS card number of the major peaks. The average crystallite size calculated from XRD data was found to vary with increasing 0.7CF-0.3BT concentration in LCM. FTIR spectroscopy indicates alterations in the main peaks with an increase in content of 0.7CF-0.3BT, suggesting the formation of triphasic composites. The upward trend in dielectric permittivity suggests the successful occurrence of Maxwell-Wagner polarization, indicating relaxor behavior at lower frequency values. Impedance spectroscopy reveals dielectric relaxation and the contribution of charge carriers in triphasic composites, along with the impact of grain and grain boundaries. Magnetization analysis at room temperature approves an increase in saturation magnetization in composites i.e., 0.7LCM-0.3(0.7CF-0.3BT) triphasic material exhibiting a maximum saturation magnetization of 13.04 emu/g. Magnetoelectric behaviour is observed in triphasic materials at different AC magnetic fields. The 0.9LCM-0.1(0.7CF-0.3BT) triphasic hydroelectric cell achieved a peak current of 1.29 mA and showed enhanced stability over time. Its I-V characteristics revealed a short-circuit current of 3.5 mA, an open-circuit voltage of 0.85 V, and an off-load power output of 2.97 mW. The triphasic system demonstrates improved structural, electrical, and hydroelectric cell (HEC) performance offering promising prospects for use in magnetoelectric and hydroelectric devices.

Preparation and performance study of a new solvent-free insulation coating for low-voltage busbar

Abstract This study focuses on low-voltage busbar insulation and is committed to developing a new solvent-free insulation coating. A coating formula with specific properties was successfully synthesized by screening and optimizing various raw materials. A comprehensive and in-depth testing and analysis were conducted on the developed coatings’ physical properties, electrical insulation performance, heat resistance, and chemical corrosion resistance. The results show that the new solvent-free insulation coating has excellent heat resistance, corrosion resistance, and mechanical strength while maintaining good insulation performance. Compared with traditional insulation coatings, its solvent-free properties effectively reduce the emission of volatile organic compounds, meeting environmental requirements. This study provides a more efficient, reliable, and environmentally friendly solution for the insulation protection of the low-voltage busbar, which has significant practical application value and broad market prospects.

A Multi-Step Framework for Measuring Post-Earthquake Recovery: Integrating Essential Infrastructure System’s Serviceability in Building Functionality

Measuring and predicting the functionality of buildings is a core aspect of community resilience analysis, which is jointly dependent on structural integrity and essential services provided by critical infrastructure systems. A functional building is one that is used for its intended services. This paper develops a multi-step community-level functionality analysis framework by modelling: (1) building functionality that integrates the building’s structural performance, essential water and electric power service performance, and physical accessibility through road networks; (2) portfolio-level building recovery by aggregating functionality of buildings for an entire community; and (3) serviceability of infrastructure systems. Graph theory is applied to assess performance of infrastructure systems. The cascading effect of water pipe failure on the road network is modelled through geographic dependency analysis. Post-earthquake water demand changes due to household dislocation and return, and increased water service demand at essential facilities are captured to model the performance of the water network under stressed conditions. The framework also assesses household-level housing recovery and integrates results with physical damage repair to more holistically depict the functional recovery of buildings from the perspective that buildings must be occupied to be fully functional. The proposed framework is illustrated for a scenario earthquake for the virtual community of Centerville. Findings provide an up-to-date measurement of post-disaster functionality for buildings and critical infrastructure systems that can guide decision-makers during pre-disaster planning and post-disaster recovery. The example demonstrates that consideration of essential infrastructure services significantly alters the functionality of the built environment during the recovery process. For instance, power outages resulted in functionality loss for 30-75% of physically operable buildings for as much as 14 days. Consideration of physical accessibility loss to nearest road segments resulted in a portfolio functionality drop of up to 9% for 6 days, and partial water shortage significantly hampered the functionality of the impacted area, including the regional hospital. Approximately 3% of households were unable to repair their damaged homes and became homeless. The proposed framework enables risk-informed decisions regarding long-term recovery at the community scale with inclusion of those living at the margins and most susceptible to long-term negative consequences from disasters.

Integration of the exploding foil initiator with capacitor discharge unit and its performance characterization

This study presents a novel integrated exploding foil initiator system (EFIs), consisting of a planar switch, an EFI chip, and a capacitor. Additionally, we propose an evaluation method for integrated EFIs that combines numerical simulations with experimental testing, enabling a thorough assessment of their performance. Under test conditions of 900 V/0.22 μF, the EFI demonstrated an inductance of 10.2 nH and a resistance of 107.5 mΩ, measured via the sampling resistance method. The operational behavior of the EFIs was analyzed through a two-dimensional metal electrical explosion model and a one-dimensional flyer propulsion model, with the results compared to experimental data. Results indicated that under 900–1200 V/0.22 μF, the deviations between measured and calculated values for electrical explosion performance and flyer velocity were both within 5 %, validating the accuracy of the evaluation approach. Firing tests further confirmed that the EFIs successfully detonated HNS-IV at 1000 V/0.22 μF.

Design of epoxy composites via molecular orbital modulation and enhanced π-πF interactions achieving synchronous improvement of electrical and mechanical performance

The stacked aromatic rings in bisphenol A epoxy resins provide good mechanical properties and thermal stability while leading to the transport of conjugated delocalized electrons, which dramatically affects the insulation properties of the material. This contradiction leads to performance bottlenecks in epoxy-based encapsulation materials, further limiting the development of high-voltage semiconductor devices. In this study, fluorophenyl-modified epoxy monomers (FPMEPs) are designed to enrich the intermolecular interactions in an aromatic system while inhibiting the charge transport process, thereby solving the contradiction between the electrical and mechanical properties. Firstly, FPMEP with high insulation properties was designed by theoretical calculations and then synthesized by highly selective click chemistry. The fluorophenyl modulates the molecular orbitals of epoxy monomers and acts as a deep trap to inhibit charge injection and transport processes. Further, the π-πF stacking between the aromatic system and fluorophenyl enhances the interaction of the matrix molecules and solves the dispersion problem of fluorinated graphene (FG) fillers. The FPMEP/FG composites thus exhibit a considerable improvement in electrical and mechanical properties (breakdown strength of 39.8 kV/mm, dielectric loss of 0.011@50 Hz, tensile strength of 68.8 MPa, and adhesive strength of 2.15 MPa), and demonstrate good water repellency and aging durability. This matrix-filler synergistic modification strategy provides new insights into the design of insulation material.

Electron field emission property of NiO-decorated ZnO nanorods grown on diamond films

ZnO/micron diamond (MCD) composite structure combines two wide-band gap semiconductor materials, providing stable performance suitable for high-performance electron field emission (EFE) devices operating in various complex environments. Nonetheless, the optical and electrochemical limitations of ZnO constrain its effectiveness. Typically, NiO can compensate these inherent defects in ZnO, thereby enhancing the performance of field-emitting devices. In this research, NiO-decorated ZnO thin films were fabricated on diamond surfaces using hydrothermal/sol-gel two-step method. The impact of varying Ni doping concentrations caused by nickel acetate solutions on the field emission properties was thoroughly investigated. Furthermore, this study involved the fabrication of NiO-decorated ZnO/micron diamond heterojunction composite structures, exploring the impact of the structure on the optoelectronic performance of the devices. The Ni doping concentration increases in the NiO films formed between the ZnO nanorods, the doped Ni exists in the ZnO/MCD composite structure as both Ni2+ and Ni3+, which are important materials for semiconductor electronic devices. The NiO decoration process induced the creation of defect levels within the bandgap of the nanorod array structure, consequently enhancing the photoluminescence performance of ZnO. Furthermore, the interaction between NiO and ZnO facilitated the formation of a p-n junction at the interface, generating an internal electric field. This electric field significantly improved the current conduction field and maximum current density of ZnO, thereby enhancing its electric field emission performance. The optical and electrical properties of ZnO nanorods doped at 0.1M exhibited the most favorable characteristics among all tested samples. At a doping concentration of 0.1 M, the turn-on electric field reaches a minimum value of 0.96 V/μm and the maximum current density J reaches a maximum value of 2.54 mA/cm2. These results offer novel insights for advancing the development of integrated broadband optical devices.

Modification of Interface Quality and Electrical Performance of ErSmO/InP Gate-Stacks by ALD-Driven HfAlOx Interlayers

Modification of Interface Quality and Electrical Performance of ErSmO/InP Gate-Stacks by ALD-Driven HfAlO_x Interlayers

Efficiency limits of concentrated solar thermophotonic converters under realistic conditions: The impact of nonradiative recombination and temperature dependence

A concentrated solar thermophotonic converter (CSTC) that efficiently harvests the entire solar spectrum under non-ideal conditions is proposed. This device includes an optical concentrator, a solar absorber, a GaAs light-emitting diode (LED) on the hot side, and an InP photovoltaic (PV) cell on the cold side. The electric power generated by the PV cell is utilized to positively bias the heated LED, resulting in a substantial increase in LED emission power. A comprehensive theoretical model is developed to accurately predict the output electrical performance and overall energy conversion efficiency of the CSTC device, especially considering the impact of the nonradiative recombination and temperature dependence. The calculated results show that when the solar concentrating factor is 30, and the LED and PV cell voltages are 0.989 V and 1.13 V, respectively, the overall peak efficiency can reach 12.8% and the corresponding output power density is 384 mW cm−2, achieving performance metrics nearly 4 orders of magnitude higher than solar thermophotovoltaics (TPV). Additionally, increasing the solar concentration ratio and decreasing the thickness of the semiconductor materials can further improve the overall output performance. This work reveals that CSTC offers several advantages over solar TPV, including more efficient conversion of narrow-spectrum electroluminescence, higher radiated power from the LED emitter, and the ability to operate at lower solar concentrations and lower costs.

Structure distortion enhanced electrical performances of Na0.25K0.25Bi2.5Nb2O9-based high-temperature piezoceramics

Na0.25K0.25Bi2.5Nb2O9-based piezoelectric ceramics are potential candidates for high-temperature applications where improving piezoelectric properties is an urgent issue. In this work, significantly improved piezoelectric properties and thermal stability of Na0.25K0.25Bi2.5-xCexNb2-yWyO9 (abbreviated NKB2.5-xCxN2-yWy, x = 0.03, y = 0.01, y = 0.03, y = 0.05) ceramics were obtained through Ce and W co-doping and using a traditional solid-state technique. The optimal composition of NaKBi2.47Ce0.03Nb1.99W0.01O9 exhibits a large piezoelectric coefficient d33 of 23.1 pC/N, maintains a high Curie temperature Tc of 690 °C, and a low tanδ of 0.006. The increase of d33 may be attributed to the structure distortion, the micro-sized domains, and the high-density domain walls. More importantly, its d33 value maintains 86 % of the initial value after being annealed at 650 °C for 2 h, whereas only 65 % for the undoped sample under the same conditions, indicating an obviously improved thermal stability. This work provides a new idea for improving piezoelectric properties and thermal stability of Na0.25K0.25Bi2.5Nb2O9-based piezoelectric ceramics.

A dual wave structure triboelectric sensor for heart rate and exercise monitoring

Recently, research on wearable devices for physiological exercise monitoring has garnered significant attention. Here, we propose a dual wave-structured triboelectric nanogenerator (DW-TENG) integrated with a cotton cloth, developed for smart running applications. The DW-TENG sensor leverages a flexible wave triboelectric layer composed of polydimethylsiloxane and silicone, with a copper electrode layer between them for sensing. This structure allows for customizable pressure sensitivity by adjusting the silicone hardness. Experimental results show that the DW-TENG achieves a sensitivity of 0.4 V kPa−1, with response and recovery times of 75 and 90 ms, respectively. The sensor effectively measures heart rate changes during various physical activities, including walking, running, and jumping. Electrical performance tests reveal that the DW-TENG’s output is significantly influenced by the silicone hardness, operational frequency, and microstructure height. The DW-TENG sensor demonstrates high durability and stability, maintaining consistent voltage output over 40 000 cycles. This research highlights the potential of the DW-TENG in multifunctional physiological and physical activity monitoring, providing real-time data on respiratory patterns, heart rate, and movement dynamics, thus enhancing athletic training, performance assessment, and health monitoring.

Papermaking-inspired sustainable triboelectric sensors for intelligent detecting system

Digitalization not only drives the intelligent transformation of industries while fostering cultural diversity and innovation. Cutting-edge triboelectric sensing technology inspired by traditional Chinese papermaking fabricates a bamboo paper-based triboelectric nanogenerator (BP-TENG). The addition of high-purity bacterial cellulose improves the structural integrity of the resulting paper. The proposed BP-TENG exhibits excellent electrical performance, generating an output voltage of 88 V and a maximum output power of 0.9 mW at a low-frequency motion of 2 Hz. Moreover, the BP-TENG is combined with machine learning algorithms to build a multi-scene intelligent detecting system, including real-time handwriting-to-speech conversion, personalized jump prediction and smart home automation systems. The machine learning algorithm can achieve a recognition accuracy of up to 99.8 %. This multi-scene intelligent detecting system boasts superior accuracy, environmental sustainability and affordability, ideal for communication security, sports health monitoring and smart building applications.

Improving mechanical and electrical contact performance of silver based electrical contact material reinforced by flower spherical zinc oxide loaded with silver nanoparticles

Flower spherical ZnO loaded with Ag nanoparticles was synthesized by hydrothermal method. Ag/ZnO electrical contact materials were prepared by powder metallurgy combined with hot extrusion technique. During the hydrothermal reaction, Ag nanoparticles entered the interlayer gaps of flower spherical ZnO and uniformly deposited on its surface. The tensile mechanical test results indicate that the Ag/ZnO electrical contact materials prepared by ZnO, Ag@ZnO(75 wt%) and Ag@ZnO(50 wt%) exhibited elongations of 6.8 %, 13.8 % and 12.1 %, respectively. This result indicates that appropriate loading of Ag nanoparticles on flower spherical ZnO could significantly improve the mechanical properties of Ag/ZnO electrical contact materials. The contact resistance of electrical contact materials significantly affects their temperature rise characteristics. During 20, 000 cycles process, Ag/ZnO electrical contact material prepared by Ag@ZnO(50 wt%) exhibited the lowest temperature rise of 6.33 K under the conditions of DC 36 V/10 A. Considering both mechanical and electrical contact performance, Ag/ZnO electrical contact materials prepared by Ag@ZnO(50 wt%) exhibited the optimum overall performance.

Improving TFT Device Performance by Changing the Thickness of the LZTO/ZTO Dual Active Layer.

The primary objective of this research paper is to explore strategies for enhancing the electrical performance of dual active layer thin film transistors (TFTs) utilizing LZTO/ZTO as the bilayer architecture. By systematically adjusting the thickness of the active layers, we achieved significant improvements in the performance of the LZTO/ZTO TFTs. An XPS analysis was performed to elucidate the impact of the varying O2 element distribution ratio within the LZTO/ZTO bilayer thin film on the TFTs performance, which was directly influenced by the modification in the active layer thickness. Furthermore, we utilized atomic force microscopy to analyze the effect of altering the active layer thickness on the surface roughness of the LZTO/ZTO bilayer film and the impact of this roughness on the TFTs electrical performance. Through the optimization of the ZTO active layer thickness, the LZTO/ZTO TFT exhibited an mobility of 10.26 cm2 V-1 s-1 and a switching current ratio of 5.7 × 107, thus highlighting the effectiveness of our approach in enhancing the electrical characteristics of the TFT device.

Overview of Fuel Cell-Hybrid Power Sources Vehicle Technology: A Review

Today, the world suffers from excessive and unfair consumption of non-renewable energy sources, such as high rate of global pollution and global warming. Accordingly, fields of life in general and industry in particular, led by the automobile industry, tended to use clean and renewable energy in industry and consumption to reduce the negative impacts on the global environment. The automotive industry tended to produce electric cars that do not depend at all on traditional energy sources from fossil fuel derivatives. Accordingly, it was necessary to find alternative energy sources that achieve both goals: avoiding the negative impact on the envi-ronment, and producing sufficient energy to achieve the requirements of performance and efficiency from the use of electric cars to be a permanent alternative to traditional cars that run on fossil fuels. This scientific paper provides an overview of one of the versions of modern technology in the field of electric vehicles energy performance to provide the vehicle with energy continuously and the mechanism of control and management in this system. This paper studies the hybrid power sources technology in electric and hybrid cars that depend on a main power source, Fuel Cells (FC), and a secondary power sources, Battery and Ultracapacitor, in the vehicle. This paper presents a brief overview of this system, its components, their characteristics, the advantages of hybridization in this type of energy source with the working mechanism of the system, an overview of the control systems in this technology and a set of challenges facing this type technology and its future perspectives.

Molecular-Scale Geometric Design: Zigzag-Structured Intrinsically Stretchable Polymer Semiconductors.

Orienting intelligence and multifunction, stretchable semiconductors are of great significance in constructing next-generation human-friendly wearable electronic devices. Nevertheless, rendering semiconducting polymers mechanical stretchability without compromising intrinsic electrical performance remains a major challenge. Combining geometry-innovated inorganic systems and structure-tailored organic semiconductors, a molecular-scale geometric design strategy is proposed to obtain high-performance intrinsically stretchable polymer semiconductors. Originating from the linear regioregular conjugated polymer and corresponding para-modified near-linear counterpart, a series of zigzag-structured semiconducting polymers are developed with diverse ortho-type and meta-type kinking units quantitatively incorporated. They showcase huge edges in realizing stretchability enhancement for conformational transition, likewise with long-range π-aggregation and short-range torsion disorder taking effect. Assisted by additional heteroatom embedment and flexible alkyl-chain attachment, mechanical stretchability and carrier mobility could afford a two-way promotion. Among zigzag-structured species, o-OC8-5% with the initial field-effect mobility up to 1.92 cm2 V-1 s-1 still delivers 1.43 and 1.37 cm2 V-1 s-1 under 100% strain with charge transport parallel and perpendicular to the stretching direction, respectively, accompanied by outstanding performance retention and cyclic stability. This molecular design strategy contributes to an in-depth exploration of prospective intrinsically stretchable semiconductors for cutting-edge electronic devices.

Theoretical studies on intrinsic electron traps in amorphous tantalum pentoxide

Charge traps in amorphous tantalum pentoxide (Ta2O5) can degrade electrical performance of electronic devices. An earlier study shows that a local region consisting of several interconnected [TaOn] polyhedrons can act as an electron trapping site in Ta2O5 cell, indicating polymer-like intrinsic electron traps (IETs). With first-principle calculations, in conjunction with molecular dynamic calculations, this work investigates the one-electron trapping behaviours of Ta2O5 in detail, including atomic configurations and electronic properties. Stable states of Ta2O5 cells with an extra electron demonstrate the existence of point-like IETs, such as a single [TaO6] polyhedron. An electron trapping at an IET can produce an electron state typically hundreds of meV below the conductive band minimum. The concentration of IETs is found to decrease exponentially with decreasing energy, and the total concentration is suggested to be of the order of 1020cm-3.

Effects of Sintering Temperature on the Electrical Performance of Ce0.8Sm0.2O1.9–Pr2NiO4 Composite Electrolyte for SOFCs

Abstract Novel composite electrolyte Sm0.2Ce0.8O1.9–Pr2NiO4 (SDC–PNO) for solid oxide fuel cells (SOFCs) was prepared. The effects of sintering temperature on the performance of SDC–PNO composite electrolyte were studied. X-ray diffraction (XRD) analysis confirms that the composite samples sintering at different temperatures contain two pure phases corresponding to SDC and PNO, respectively. It indicates that there is no interfacial reaction between Sm0.2Ce0.8O1.9 and Pr2NiO4, and the composite electrolyte keeps regular grain boundaries after long-term operation. The results of scanning electron microscopy (SEM) show that a dense structure can be formed after sintering at 1250 °C. The electrical properties were tested in air by electrochemical impedance spectroscopy technique in the temperature range of 400–800 °C. Results show that an appropriate increase of the sintering temperature can effectively increase the conductivity of SDC–PNO composite electrolyte, and the maximum conductivity of 0.102 S/cm can be obtained in the sample sintered at 1250 °C and tested at 800 °C. In summary, the electrical conductivity of Sm0.2Ce0.8O1.9 can be significantly increased by adding Pr2NiO4, and SDC–PNO composite electrolyte is a promising electrolyte for solid oxide fuel cells.