Electrical Performance Research Articles

The Symmetric Dual Inductor Hybrid Converter for Direct 48V-to-PoL Conversion

This work introduces the symmetric dual inductor hybrid (SDIH) dc-dc converter topology, which is suitable for large conversion ratios where regulation is required, such as direct 48 V to point-of-load (PoL) applications. A dickson-type switched capacitor network is used to effectively produce two interleaved PWM outputs with a greatly reduced voltage amplitude relative to the input voltage, allowing the subsequent magnetic volume to be reduced while retaining modest switching frequencies. Distinct from related variations, part count is significantly reduced while both even and odd order switched capacitor networks can be used with straightforward split-phase control; allowing either network type to achieve complete soft-charging of all flying capacitors. Additionally, charge flow is uniformly distributed through all elements, with equal capacitor and inductor values being preferred. Subsequently this topology is expected to simplify component selection, improve electrical and thermal performance, and reduce cost. Furthermore, analysis is presented that calculates precise phase durations without making small ripple assumptions, revealing up to a 75% timing error in cases where either inductor or capacitor ripple is ignored. Finally, a discrete prototype validates this analysis and demonstrates very high measured power densities of 1,029 W/in <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{3}$</tex-math></inline-formula> , 754 W/in <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{3}$</tex-math></inline-formula> , and 663 W/in <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{3}$</tex-math></inline-formula> for 48 V input and regulated output voltages of 3 V, 2 V, and 1 V, respectively, while switching at a frequency of 750 kHz.

Eco-friendly aqueous spinning of robust and porous carbon nanotube/graphene hybrid microelectrodes: The graphene oxide size effect

An eco-friendly, cost-effective, and scalable aqueous spinning of robust and porous hybrid fibers consisting of carbon nanotubes (CNTs) and graphene has been developed. We focus on the design of nanoarchitecture within CNT fibers involving the precise control of CNT bundle size and alignment, porosity, and the interaction between CNTs and Graphene. The effect of graphene oxides (GO) sizes on the quality of CNT/GO aqueous dispersions and the structures/properties of the as-spun fibers was investigated, and nano-sized GO was found to be most effective in reducing CNT bundle size, improving CNT alignment, and strengthening the fibers. After high-temperature treatment, the specific strength and specific conductivity of these CNT/graphene hybrid fibers reached to 1.02 N/tex and 1202.01 S m2/g, which were 7.39 and 1.21 times higher than those of pure CNT fibers. Meanwhile, the CNT/graphene hybrid fibers also have a high specific capacity of 168F g−1. The combination of high mechanical, electrical, and electrochemical performances makes the CNT/graphene hybrid fibers promising materials for wearable electronics.

Fabrication of PVA-based electromagnetic interference shielding composite film by improving the dispersibility of carbon nanomaterial via m-LDH modification

A good dispersion of carbon (C) nanoparticles is a crucial factor to ensure good electrical conductivity and electromagnetic interference shielding effectiveness (EMI SE) performance of polymer-based composite films. In the present work, water-dispersed monolayer layered double hydroxides (m-LDH) was used to modify the C nanoparticles via an in-situ growth method and applied as the conductive fillers for polyvinyl alcohol (PVA) composite films. The prepared C@m-LDH hybrids displayed good water dispersibility due to the in-situ growth of m-LDH with high dispersibility and small particle size on the surface of C nanoparticles, as well as the synergistic effect of styrene-maleic anhydride copolymer attached to the m-LDH surface. The property testing experiments for the PVA composite films demonstrated that compared with pristine C nanoparticles, as-prepared C@m-LDH hybrids exhibited greatly enhanced the electrical conductivity and higher EMI SE performance. Moreover, PVA/C@m-LDH composite film exhibit remarkably low permeation thresholds, especially PVA/CB@m-LDH composite film, CB@m-LDH content is only 0.4 wt%. In order to further improve the electrical conductivity and EMI SE performance, hybrid fillers of CB@m-LDH/CNT@m-LDH were added in the composite films with different mass ratios. Among, the polymer composite films containing 30 wt% CB@m-LDH/CNT@m-LDH with a mass ratio of 12:1 achieves a high EMI SE value up to 29 dB at a thickness of 0.2 mm, indicating the potential use of these materials for electromagnetic shielding application in the X-band frequency region. The present study paves the way for designing high-performance polymer-based composite film by Cnanoparticles functionalization and altering processing conditions for efficient microwave shielding material.

Experimentally thermal management of low-concentrated photovoltaic via new configurations of dimple/trapezoidal heat spreaders of different sizes

ABSTRACT This study experimentally investigates the influence of dimple (DHS), flat plate (FHS), and trapezoidal heat spreader (THS) cooling systems on thermal regulation of low concentrated solar cell (LCPV). It is performed at 1.5 and 2 HS/PV area ratio and HS thicknesses 1 and 2 cm under 3100 W/m2 solar irradiance. Results reveal that using DHS outperforms other cooling systems in terms of cell temperature and electric performance. Increasing HS area ratio and thickness significantly enhances PV performance. DHS, PHS, and THS achieve maximum PV temperature reduction of 44.4, 43.2, and 41°C and PV efficiency improvement of 16.89%, 14.87%, and 13.9%, respectively.

Preparation of polyimide bond-linked covalent organic frameworks as resin-compatible nanofillers for copper clad laminates with improved thermal and electrical performances

Preparation of polyimide bond-linked covalent organic frameworks as resin-compatible nanofillers for copper clad laminates with improved thermal and electrical performances

Optimizing electrical and thermal performance in AlGaN/GaN HEMT devices using dual‐metal gate technology

AbstractThe investigation of aluminum gallium nitride/gallium nitride high electron mobility transistor (AlGaN/GaN HEMT) devices with a dual‐metal gate (DMG) structure encompasses both electrical and thermal characteristics. As efforts to enhance heat dissipation progress, there is a concurrent exploration of novel semiconductor materials boasting high thermal conductivity, like boron arsenide and phosphide. Combining these materials into a model and measuring their interface achieves efficient energy transport. Minimizing the self‐heating impact in AlGaN/GaN HEMTs is essential for enhancing device efficiency. This research exposes the heterogenous combination of boron arsenide and phosphide cooling substrates with metals, GaN semiconductors and HEMT. In this research, the autoencoder deep neural network techniques in GaN HEMT for self‐heat reduction is driven by the ability to effectively analyze and model the thermal behavior of the device. Autoencoders learn complex relationships within temperature data and identify patterns associated with self‐heating. By leveraging these learned representations, the deep neural network optimizes control strategies to mitigate self‐heating effects in GaN HEMT devices, ultimately contributing to improved thermal management and enhanced overall performance. In this research, the use of genetic algorithms in GaN HEMT aims to optimize device parameters systematically, to minimize self‐heating effects and enhance overall thermal performance. The structure also enhances electron mobility within the channel. Results show DMG structures, exhibiting higher saturation output currents and transconductance despite self‐heating. The DMG exhibits a maximum gm value of 0.164 S/mm, which is 10% higher significantly enhancing GaN‐based HEMTs for improved reliability and efficiency in various applications.

A comparative study of C, N and Xe pre-amorphization implantation processes for improving the thermal stability of NiSi films

In this paper, a comparative study of C-, N- and Xe-based pre-amorphization implantation (PAI) processes is proposed. The impact of the use of such processes on the agglomeration resistance and physical properties of the final Ni(Pt)Si layer, as well as the formation mechanisms via solid-state reactions and electrical performances via the transfer length measurement (TLM) method, is evaluated. It is shown that although all species are able to increase the agglomeration temperature of Ni(Pt)Si layers (up to more than 100 °C), the underlying mechanisms are different. For C- and N-based PAI processes a strong chemical effect is observed, while for Xe-based processes the amorphization depth plays an important role. Consequently, the beneficial effect of stabilizing Ni(Pt)Si layers at high temperatures using C- and N-based PAI processes has to be balanced with an increased layer resistivity (up to 30%) combined with a strong deterioration of the associated specific contact resistivity (which is multiplied by almost a factor 10). In this sense, Xe-based PAI processes seem to be a better option as they could allow to combine both requirements.

The Influence of Discontinuity‐Induced Fringing Effect on the Output Performance of Contact‐Separation Mode Triboelectric Nanogenerators: Experiment and Modeling Studies

Triboelectric nanogenerators (TENGs) are promising self‐powering supplies for various intelligent sensing and monitoring devices, especially because they can harvest electric energy from low frequency and small‐scale mechanical motions. Despite the fact that contact‐separation mode TENGs with smaller contact areas harvest higher electrical outputs due to fringing effect, the impact of fringing effect on TENGs’ electrical outputs is rarely investigated quantitatively. Herein, in this study, the influence of fringing effect on the electrical outputs of contact‐separation mode TENGs by introducing discontinuity on the tribo‐negative side manually is investigated. In the results, it is revealed that the TENGs with more discontinuities show higher overall electric performance. Compared to pristine TENGs, the TENGs with discontinuity increased significantly, improving the surface charge by 50% and the power density by 114% when cross discontinuities are applied. However, one should generate discontinuities on tribo‐negative side of TENGs using ceramic blade instead of metal blade within a positive‐ion atmosphere due to the neutralization through the electrically conductive metal blade. The computational simulation validates that the TENGs with discontinuities obtain higher electrical outputs, and further investigates the effect of discontinuity gap size and array distance on TENGs performance. In this study, a promising method is provided for the future design of TENGs using discontinuous structures.

Outcomes of leadless pacemaker in chronic kidney disease patients: real-world data from the i-LEAPER registry

Abstract Background Chronic kidney disease (CKD) represents a major risk factor for patients requiring transvenous pacemaker (TV-PM), resulting in a high rate of operative complications and PM-related infection rate (21.9% and 12.5%, respectively), with both complications parallels to severity of CKD. Moreover, TV leads represent an important concern for end-stage CKD patients, often needing vascular access patency for renal replacement therapy. In this setting leadless pacemakers (LPMs) represent an attractive alternative to TV-PM for their lower device-related infection rate and the absence of TV leads. To date, limited data on LPM safety and efficacy profile in CKD patients are available. Purpose to assess operative and long-term safety and efficacy of LPMs implantation in patients with different stages of CKD in the real-world setting. Methods Consecutive patients who underwent LPM implantation in 12 European centers joining the i-LEAPER registry were retrospectively enrolled. CKD stage was assessed according to CKD-EPI equation for eGFR. Patients with CKD stage G3a/b (N=245) and stage G4/G5 (N=67) were compared with patients with normal kidney function (NKF) (N=867). Primary safety endpoint was LPM-related major complications rate at implant and during follow-up (FU). Additionally, the rate of patients showing sub-optimal electrical performance (pacing threshold [PT] &amp;gt;1V@0.24ms) was compared between groups. Results 1179 patients were enrolled and followed for a median of 33 [IQR 24-47] months. When compared with the NKF group, patients with CKD stage G3a/b and stage G4/G5 showed a higher burden of cardiovascular comorbidities (Table 1). The choice of a LPM was mainly due to vascular concern in the CKD stage G4/G5 group, while a perceived highest infective risk was reported in CKD stage G3a/b group (Table 1). Major complication rate at implant and during FU did not differ between groups, regardless of renal impairment stage (Table 2). All-cause mortality incidence resulted higher in CKD stage G4/G5 group when compared with NKF group (17.9% vs 6.8%; HR 4.24; 95%CI 4.25-7.94, p&amp;lt;0.001) (Figure A). The rate of patients with PT&amp;gt;V1@0.24ms during FU did not differ between groups, not exceeding 13.8%, and therefore remaining consistent with historical data for LPM (Figure B). Conclusion In the real-world setting, LPM showed a remarkable safety and efficacy profile in CKD patients regardless of renal impairment stage that was comparable to NKF population. LPM should be considered as first choice in CKD patients requiring a PM.

Optimising electrical performance of leadless cardiac resynchronisation therapy and leadless LV septal pacing

Abstract Introduction Leadless left ventricular (LV) endocardial pacing with the WiSE-CRT System is an emerging form of cardiac resynchronisation therapy (CRT). The system was designed to provide lateral wall LV pacing (LVP) via an endocardial receiver electrode in response to detection of a right ventricular pacing (RVP) stimulus from a co-implanted device, thereby delivering near-simultaneous biventricular pacing (BiVP). However, it is unclear whether BiVP generates the optimal electrical performance in this system, particularly in the context of leadless LV septal pacing, a novel use for leadless CRT. Aim We aimed to characterise the acute performance of leadless CRT at different pacing modalities using electrocardiographic imaging (ECGi). Methods Patients with the leadless CRT underwent an acute ECGi study. The following pacing modalities were tested: RVP; BiVP; LVP; and LVP with an electrically optimised atrioventricular delay (LV-OPT) in patients with sinus rhythm (SR). Reconstructed epicardial electrograms (Figure 1) were used to calculate BiV activation time (BIVAT-90), LV activation time (LVAT-90), RV activation time (RVAT-90), LV dyssynchrony index (LVDI), and BiV dyssynchrony index (BIVDI). For each metric, the improvement compared to baseline rhythm was calculated, and the optimal pacing modality (OPM) in each patient was determined. Results Ten patients were studied, 5 receiving septal LVP, and 5 receiving lateral LVP. The underlying rhythm in 4 patients was SR with left bundle branch block (LBBB), and atrial fibrillation (AF) with complete heart block (CHB) in the remaining 6. BiVP generated a 23.7% improvement in BiVAT-90 compared to baseline (p=0.002). An individualised OPM resulted in a 43.3% BiVAT-90 improvement compared to baseline (p=0.0001), thus a 19.6% improvement compared to BiVP (p=0.02, Figure 2A). Using an OPM, BiVAT-90 was significantly improved in both patients with lateral (43.3%, p=0.0001) and septal LVP (42.4%, p=0.009). The BiVAT-90 OPM varied between patients (Figure 2B). BiVP was the OPM in 4/10 patients, all of whom had AF with CHB. BiVP was the OPM in 1/5 patients receiving LV septal pacing, with LVP or LV-OPT performing best in the remaining 4. In 3/4 patients in SR, LV-OPT was the OPM. Choosing the OPM increased performance primarily through significant improvements in RVAT-90 compared to BiVP (36.5% versus -8.2%, p =0.002). Conclusion Leadless CRT, both with lateral and septal LVP, significantly reduces electrical activation times and improves electrical dyssynchrony. Individualised selection of the OPM may be required with leadless CRT to accommodate for varying conduction disease phenotypes and implant locations.

Spin coating high‐k multicomponent (Al,Ti,V,Zr,Hf)Ox films with sub‐nm EOT for MOS‐based electronic devices

AbstractThe facile spin coating fabrication of high‐dielectric‐constant (high‐k) multicomponent (Al,Ti,V,Zr,Hf)Ox films with an equivalent oxide thickness of ≈0.95 nm and the investigation of their thermal stability and dielectric and electrical properties of the resulting advanced metal–oxide–semiconductor (MOS)‐based electronic devices are reported in this study. Various heating conditions, including drying following spin coating, annealing after drying, and forming gas annealing, were investigated to optimize the quality of the films and reduce film defects. The favorable film‐based MOS devices exhibited robust capacitance–voltage (C–V) and current–voltage (I–V) characteristics with a remarkable k value of approximately 62 at 1 kHz. The thermal stability of the films was affirmed through a rapid thermal annealing treatment at 900°C for 5 s and observation of nondegraded C–V and I–V curves. The electrical performance of the resulting MOS field‐effect transistors (MOSFETs), including a threshold voltage of 0.4 V, an on/off ratio of 106, a saturated mobility of 40.1 cm2 V−1 s−1, and a subthreshold swing of 66.7 mV dec−1, was obtained. Moreover, hole‐ and electron‐trapping measurements through negative and positive gate bias stress instabilities, respectively, indicate the reliable performance of our MOSFETs. Our results imply that solution‐based processes are promising for fabricating fundamental semiconductor devices.

Combined effects of substrate temperature and post annealing temperature on structural, optical and electrical properties of Sb-doped SnO2 films

Sb-doped SnO2 (ATO) films have received extensive attention as transparent conductive films, but there is still a lack of in-depth and systematic study on combined effects of substrate temperature (Ts) and annealing temperature (Ta) on their transparent conductive properties. In this study, ATO films were prepared using RF magnetron sputtering at RT∼400 ℃ and subsequently annealed at 200–1000 ℃. The results show that the conductive properties of the films enhance (with a decrease in resistivity from 1.15×10-1 to 2.15×10-3 Ω•cm) and the average visible-light transmittance (TVis) decreases (90.16 → 38.24%) with increase of Ts. With the increase of Ta, the conductive properties of the films prepared at different Ts tend to first enhance and then degrade, and the TVis basically shows a trend of first decreasing and then increasing. After annealing at 600 ℃, the films prepared at RT and 100 ℃ can achieve better comprehensive properties (resistivity of 2.50×10-3 and 1.64×10-3 Ω•cm, carrier concentration of 3.35×1020 and 4.93×1020 cm-3, mobility of 7.73 and 7.76 cm2/V•s, sheet resistance of 84 and 55 Ω/sq., and TVis of 86.63 and 79.50%). In order to explore the intrinsic mechanism of the optical and electrical performance of ATO films changing with Ts and Ta, the preferred orientation, crystallinity, and stress state of the films were analyzed by XRD, and their surface morphology was observed by SEM. Meanwhile, the chemical states of Sn, O and Sb as well as Sb content in the films were analyzed by XPS, and their lattice vibration modes of the film were studied by Raman spectra. Finally, the process-structure-properties correlations were established for the ATO films.

Very early fractures of the stylet-driven Biotronik Solia lead used for left bundle branch area pacing

Abstract Introduction Left bundle branch area pacing (LBBAP) has become increasingly popular due to the relatively simple implantation procedure allowing for conduction system pacing (CSP). Initially, lumen-less leads have been used primarily for CSP. However, several authors have published encouraging results using conventional stylet-driven pacemaker (PM) leads as well and our centers have largely adopted this approach. Methods In our two tertiary referral centers, we assessed all patients, who underwent a LBBAP lead implantation using any lead. We observed several early lead fractures, exhibiting a unique failure mechanism, which we illustrate in this case-series. Results Between January 2022 and November 2023 343/393 patients (87.3%) were implanted with a Solia pacemaker lead, 46/393 (11.7%) received a SelectSecure 3830 lead, and 4/393 (1.0%) another stylet-driven lead. Three patients (0.8%) who initially were implanted with a Solia lead experienced very early intracardiac lead fractures within 1, 11 and 13 months after implantation despite good initial electrical performance values (Table shows initial values and values during the time of failure (bold)). The first case was a 54 year-old woman with permanent 3d degree AV block receiving an LBBAP lead after lead extraction. Four weeks later, she presented with presyncope and exit block at maximum output in uni- and bipolar configuration. The second case was a 72 year-old man with intermittent 3rd degree AV block in the context of an ischemic heart disease. He received a dual-chamber LBBAP PM. 13 months after the implantation, a bipolar impedance &amp;gt; 2’500Ω and exit block were noted. The third case was 65 year-old man suffering from sick sinus syndrome. He initially underwent a dual-chamber PM implantation in 2011 and due to ventricular sensing issues a transvenous lead extraction and implantation of a LBBAP lead in October 2022. During device follow-up after 11 months, a fractured LBBAP lead with bipolar impedance &amp;gt;2’500Ω and exit block during threshold testing was noticed. In all cases, X-rays and macroscopic analysis consistently showed a disintegration of the lead immediately distal to the ring electrode (Figure; site of fracture marked with an arrow). Most likely, this was caused by the repetitive shear stress at the hinge point of the lead where it is entering the septum. Conclusion No dedicated stylet-driven CSP lead is available to date. The implantation site and technique for LBBAP may exert higher mechanical stress on the distal part of the lead, making it more prone to fracture than in a conventional position. Currently, the use of conventional stylet-driven leads is still off-label and the performance of such leads should be monitored closely.TableFigure

Optimizing sewage water of Perum Pesona Permata Gading with the assistance of Cu/Mg electrodes as public street lighting based on green technology electricity

Electricity in Indonesia uses fossil fuels as an energy source. If fossil fuels run out, we will lose our largest source of electrical energy. Therefore, we need a way to reduce dependence on fossil fuels by making good use of renewable energy as a source of electrical energy. One of them is Green Technology Electricity with the utilization of sewage water to convert chemical energy into electrical energy. This study aims to determine the potential of sewage water assisted by Cu/Mg electrodes as a source of street lighting, manufacturing, and testing methods, and the effect of optimizing sewage water on electrical performance as street lighting. Lack of lighting in residential areas is also a supporting factor in this research. The stages used are preparation, incubation, construction assembly, research, and strength testing. Based on research, the sewage water from Perum Pesona Permata Gading can be used as street lighting with the highest potential difference and current strength being 4.4 V and 0.55 A for each 50 mL of the sewage water.

Upgrade and Performance Evaluation of G8+ Large-size Cast Mono-Si Ingot

With the rapid growth of CZ mono-Si solar cell technology in the global market, the development of cast mono-Si faces challenges in terms of crystal quality and cost. This study introduces the first preparation of a G8+ large-size casting furnace by upgrading a G7 furnace to enhance casting mono-Si's performance and economic benefits. The effects of the G8+ casting furnace on the preparation cost of mono-Si ingot, crystal quality and its impact on the performance of solar cells were thoroughly investigated. Modifying the thermal field and optimizing the seed pavement strategy increased the G8+ cast mono-Si ingot weight to 1600kg, raised the monocrystalline ratio to approximately 98%, and achieved an effective yield exceeding 50%. Solar cells made from G8+ cast mono-Si demonstrated electrical performance comparable to CZ mono-Si cells, achieving an average efficiency of 22.64% with only a 0.3% efficiency gap. Consequently, the upsizing of cast mono-Si ingots and adopting rigorous defect control strategies could significantly enhance the electrical performance and manufacturing productivity of cast mono-Si.

Enhanced response over wavelength range of 7–12 µm for quantum wells in asymmetric micro-pillars

Efficient coupling in broad wavelength range is desirable for wide-spectrum infrared light detection, yet this is a challenge for intersubband transition in semiconductor quantum wells (QWs). High-Q cavities mostly intensify the absorption at peak wavelengths but with shrinking bandwidth. Here, we propose a novel approach to expand the operating spectral range of the Quantum Well Infrared Photodetectors (QWIPs). By processing the QWs into asymmetric micro-pillar array structure, the device demonstrates a substantial enhancement in spectral response across the wavelength from 7.1 µm to 12.3 µm with guided mode resonance (GMR) effects. The blackbody responsivity is then increased by 3 times compared to that of the 45° polished edge-coupled counterpart. Meanwhile, the dark current density remains unchanged after the deep etching process, which will benefit the electrical performance of the detector with reduced volume duty ratio. In contrast to the symmetric micro-pillar array that contains simple resonance mode, the detectivity of QWIP in asymmetric pillar structure is found to be improved by 2-4 times within the range of 9.5 µm to 15 µm.

Numerical Investigation of Innovative Photovoltaic–Thermal (PVT) Collector Designs for Electrical and Thermal Enhancement

Photovoltaic–thermal (PVT) technology is gaining popularity due to the diminishing availability of traditional fossil fuels and escalating environmental concerns. Enhancing the heat dissipation of PVT to improve its electrical and thermal performance remains a significant task. This study simulates the thermodynamic and heat transfer characteristics in multiple novel PVT structures by examining the impact of various factors such as collector materials, radiation intensity, mass flow rate, and inlet temperature. This work also identifies the optimal mass flow rate for locations with different solar radiation. The numerical results indicate that the electrical efficiency of a designed cylindrical structure has increased by 1.73% while the thermal efficiency has increased by 8.29%. Aluminum is identified as the most cost-effective material for the collector. The optimal mass flow rates in selected locations of Xining, Taiyuan, and Turpan are 0.36 kg/s, 0.35 kg/s, and 0.30 kg/s, respectively. The numerical results provide valuable insight into optimizing the design and operating conditions of PVT systems.

Multifunctional electronic skins for ultra-sensitive strain, temperature, humidity sensing, and energy harvesting

Though gaining increasing attention in various portable and wireless electronic devices and sensors, flexible gels used in strain sensors and triboelectric nanogenerators (TENGs) still suffer from inferior mechanical properties and lack long-term stability. Herein, multifunctional electronic skins (e-skin) from oriented 2D nanosheets enhanced eutectogel were facilely fabricated via a one-step curing strategy with excellent transparency (96%), superb elasticity (1613%), toughness (17.22 MPa). Moreover, the multifunctional e-skin also exhibits temperature and humidity sensibility. Notably, the as-assembled TENG e-skin exhibits high and stable electrical output performances, including an open-circuit voltage of 224 V, short-circuit current of 7.1 μA, and short-circuit charge of 640 nC. Meanwhile, the TENG can easily light up 130 LEDs, charge capacitors to drive a calculator, and sustain a long service life (120 days). Furthermore, it can serve as a self-powered biomechanical sensor to realize the real-time monitoring of various human motions, showing application potentials in wearable electronics, human health management, and energy harvesting systems.

Alleviating the Angular Dependence of Perovskite Solar Cells via Light‐Harvesting Nanostructure

Over the past decade, perovskite solar cells (PSCs) have witnessed a remarkable surge in power conversion efficiency (PCE). However, the electrical output performance of PSCs is dependent on the incident angle of solar radiation, and energy loss occurs during photovoltaic conversion when light impinges at angles. Herein, a perovskite‐light‐absorbed layer with inverse opal structure is used to fabricate PSCs and reduce the angular dependence of the performance. In the results, it is demonstrated that ordered periodic perovskite inverse opal (PVSK–IO) not only exhibits a remarkable slow‐photon effect for enhancing the absorption of sunlight near the photonic bandgap (PBG), but also promotes the carrier transfer by expanding the contact area with hole‐transport layer. Moreover, the slow‐photon region of PBG can be intentionally tuned by changing the direction of sunlight illumination, thereby more intuitively delaying and storing light in the PVSK–IO layer. As a consequence, the slow‐photon effect originated from the PVSK–IO structure efficiently improves the short‐circuit current density, resulting in a higher PCE than that of planar devices under the irradiation from different incident angles. In this research, a rational strategy is offered for enhancing the performance of PSCs while alleviating their angular dependence.

Effect of Nb Doping on the Electrical Contact Properties of AgNi Contact Materials

AgNi contact materials have received widespread attention with the acceleration of the process of replacing AgCdO contact materials. However, the practical applications of AgNi contact materials are limited due to its disadvantage of poor resistance to melting welding. Firstly, following the first principles of the density functional theory, we simulated and tested an interfacial model of AgNi doped with varying amounts of Nb. Next, we fabricated AgNi electrical contact materials. Subsequently, we conducted electrical contact tests. Finally, the impact of Nb doping on the arc erosion behavior of AgNi electrical contact materials was analyzed. The results indicate that, with an increase in Nb doping content, the electrical contact performance and the degree of arc erosion exhibit a trend of initially decreasing and then increasing, which aligns with the simulation results. The mean values of arc energy, arc duration, and welding force for the material doped with 4.55% Nb were 181.02 mJ, 9.43 mS, and 38.45 cN, respectively. Moreover, the anode is more responsive to changes in Nb content compared to the cathode. The introduction of Nb enhances the viscosity of the molten pool in the AgNi electrical contact. Furthermore, the mechanisms of grain boundary strengthening and solid solution strengthening by Nb improve the weld performance resistance of the contact.