Efficient Devices Research Articles

Flexible solid-state supercapacitors based on biowaste-derived activated carbon and nanomaterials for enhanced performance.

Supercapacitors are energy storage devices with long cycle life that can harvest and deliver high power. This makes them attractive for a broad range of applications including flexible and lightweight wearable consumer electronics. In this work, we fabricate flexible solid-state supercapacitors with improved capacitance and cycle life. We synthesize activated carbon (AC) from cabbage leaves as a low cost, biowaste-derived active electrode material. To improve mechanical flexibility and conductivity, we incorporate reduced graphene oxide sheets (RGO) and carbon quantum dots (CQDs) into the electrodes. We show that at the optimum AC/RGO/CQD composition, the capacitance of the solid-state supercapacitor is maximized while its scan rate dependence and bending stability are simultaneously improved. We envision that this approach offers significant potential for delivering efficient energy storage devices for consumer electronics.

The Distance‐Dependent Electric Field Theory for Sliding Mode Triboelectric Nanogenerators

AbstractTriboelectric nanogenerators (TENGs) have demonstrated outstanding potential as energy harvesters and sensors for future wearable electronics. However, TENGs still require major improvements in their theory and optimization, especially for the sliding‐mode designs. Addressing this gap, a novel theoretical model based on the distance‐dependent electric field (DDEF) theory for sliding mode TENGs is presented here. The model is used to simulate the electrical outputs and impedance behaviour of a sliding mode TENG, and the results are verified experimentally. The outcomes indicate that compared to existing theoretical models, this new model provides higher accuracy in representing experimental TENG. Next, all the primary parameters (material, structural and motion parameters) which affect the sliding mode TENG are analyzed, uncovering new optimization strategies and more comprehensive parametric analysis compared to previous models. More importantly, the theoretical approach is equally applicable to sliding mode TENG as well as contact‐separation mode TENG. This eliminates the need for bespoke capacitor models for each TENG type, leading to a universal theoretical platform for TENGs. The new model facilitates cross‐comparison between different TENG working modes, uncovering a range of previously unreported output trends. Hence, this work significantly expands the understanding of TENGs, paving way to more efficient future device designs.

Carboxymethyl‐Based Ionic Liquid Engineering for Efficient and Stable Inverted Perovskite Solar Cells

Perovskite solar cells (PSCs) have garnered significant attention due to their tunable bandgap, superior charge carrier properties, and easy fabrication processes, making them highly efficient energy conversion devices. Despite these advantages, nonradiative recombination due to defects in the perovskite layer continues to limit performance. This study addresses this issue by introducing 1‐CarboxyMethyl‐3‐MethylImidazolium chloride (ImAcCl) into precursor solution to enhance film quality and suppress defect‐induced recombination. The carboxylate groups (CO) and hydrogen donors (NH) in ImAcCl form coordination and hydrogen bonds, helping to reduce defect density of the perovskite film. Additive ImAcCl improves crystallinity, reduces surface roughness, and enhances charge carrier transport, leading to higher photovoltaic performance. With the ImAcCl additive, the power conversion efficiency and short‐circuit current of PSCs significantly improve by 23.92% and 25.35 mA cm−2, with a notable reduction in nonradiative recombination losses. This study highlights the significant potential of ImAcCl as an effective additive for defect passivation in PSCs, offering a promising pathway toward further efficiency improvements in next‐generation solar cells.

Recent Developments in Electrospun Nanofiber-Based Triboelectric Nanogenerators: Materials, Structure, and Applications

Triboelectric nanogenerators (TENGs) have garnered significant attention due to their high energy conversion efficiency and extensive application potential in energy harvesting and self-powered devices. Recent advancements in electrospun nanofibers, attributed to their outstanding mechanical properties and tailored surface characteristics, have meant that they can be used as a critical material for enhancing TENGs performance. This review provides a comprehensive overview of the developments in electrospun nanofiber-based TENGs. It begins with an exploration of the fundamental principles behind electrospinning and triboelectricity, followed by a detailed examination of the application and performance of various polymer materials, including poly (vinylidene fluoride) (PVDF), polyamide (PA), thermoplastic polyurethane (TPU), polyacrylonitrile (PAN), and other significant polymers. Furthermore, this review analyzes the influence of diverse structural designs—such as fiber architectures, bionic configurations, and multilayer structures—on the performance of TENGs. Applications across self-powered devices, environmental energy harvesting, and wearable technologies are discussed. The review concludes by highlighting current challenges and outlining future research directions, offering valuable insights for researchers and engineers in the field.

扒齿输送带式荞麦捡拾装置的设计与试验研究

To address the high rate of grain loss in the two-stage harvest of buckwheat, a pickup-tooth conveyor belt type buckwheat pickup device was developed to mitigate the grain loss in the buckwheat pickup process. The critical components of the pickup mechanism and conveyor mechanism were designed, and the essential parameters were determined. The operational efficiency of pickup-tooth conveyor belt type buckwheat pickup device was verified through field orthogonal test. The field test results indicate that the loss rate is most significantly affected by the speed of the pickup device, followed by the tilt angle of the pickup-tooth. The forward speed of the machine exerts minimal influence. After the multi-objective parameters of the regression equation model were optimized, the optimal parameters of the factors were obtained: the forward speed of the machine of 0.8 m/s, the pickup speed of 1.1 m/s, as well as the pickup-tooth tilt angle of 0°, Under the above condition, the loss rate of buckwheat grain reached 6.92%.

MICROHARDNESS OF SINGLE CRYSTALS OF Ag7+x(P1-xGex)S6 SOLID SOLUTIONS

Superionic conductors have a number of important characteristics and applications that make them important in the field of materials science, technology and industry. At the same time, when developing and analyzing the properties of new materials to optimize their composition and material processing, information about microhardness is mandatory. This is important to ensure the stability and efficiency of devices over a long period of time. This paper presents a study of the microhardness of single-crystal samples of Ag7+x(P1-xGex)S6 (x = 0, 0.1, 0.25, 0.33, 0.5, 0.75, 1) solid solutions. For all the studied samples, a decrease in the microhardness H is observed with an increase in the load P, indicating the presence of a direct size effect. The microhardness of single-crystal samples is also described within the PSR (proportional specimen resistance) model, the results of which also indicate the presence of a direct size effect. The values of the intrinsic hardness H0 calculated within the PSR model for solid solutions of Ag7+x(P1-xGex)S6 (x = 0, 0.1, 0.25, 0.33, 0.5, 0.75, 1) are as follows: 903.1 N/mm2 (x=0), 997.7 N/mm2 (x=0.1), 990.2 N/mm2 (x=0.25), 1019.9 N/mm2 (x=0.33), 1053.3 N/mm2 (x=0.5), 1097.8 N/mm2 (x=0.75), 1081.1 N/mm2 (x=0.1). To assess the influence of the direct size effect, Meyer's law was used. For the studied solid solutions of Ag7+x(P1-xGex)S6, the values of the Meyer's index are in the range n = 1.72 ÷ 1.86, which indicates that these solid solutions belong to soft materials.

Unraveling the relaxation dynamics of donor-π-acceptor porphyrins, achieving a promising 10.51% device efficiency in dye-sensitized solar cells

Unraveling the relaxation dynamics of donor-π-acceptor porphyrins, achieving a promising 10.51% device efficiency in dye-sensitized solar cells

Enhanced Efficiency and Stability of Triple-Cation Perovskite Solar Cells through Engineering of the Cell Interface with Phenylethylammonium Thiocyanate.

It is reported that the tricationic mixed halide perovskite Csx(FAyMA1-y)1-xPb(IzBr1-z)3 (CsFAMA) possesses a stable crystal structure and outstanding bandgap tunability, rendering it one of the most competitive candidates for commercial perovskite solar cells (PSCs). Nevertheless, the numerous defects at the interface of the tricationic perovskite give rise to a significant constraint on the light capture performance of the device. Simultaneously, water molecules form intermediate compounds with the perovskite at the interface via hydrogen bonds, accelerating the degradation of the perovskite. This study reports the introduction of two-dimensional (2D) phenylethylthiocyanate (PEASCN) at the interface of three-dimensional (3D) perovskite. This approach significantly passivates the surface defects of the perovskite. Concurrently, due to the propensity of the organic ammonium cation PEA+ to interact with the FA+ base within the perovskite, SCN- is exposed outward to form a small-molecule hydrophobic layer. This method markedly reduces the loss of charge recombination and significantly enhances the device stability. The results indicate that the efficiency of the conventional device treated solely with PEASCN is as high as 23.94%. The unsealed device retains 85.12% of its initial efficiency after being placed in a conventional environment for 500 h. Furthermore, this surface passivation and hydrophobic strategy can be universally applicable to perovskite types with a high FA+ content.

Design and implementation of a scalable and high-throughput EEG acquisition and analysis system

Recent advances in neuroscience, neuromorphic intelligence, and brain–computer interface (BCI) technologies have created a need for fast, efficient, and convenient electroencephalogram (EEG) data acquisition systems. However, the existing equipment was limited in its flexibility, restricting non-invasive studies to research or medical settings. To address this issue, low-cost, compact EEG acquisition devices have been developed, allowing for frequent and flexible brain data acquisition in various scenarios. This paper introduces a scalable and high-throughput EEG signal acquisition and analysis system based on field-programmable gate array (FPGA) technology. The proposed system offers electrode scalability, on-chip computing, and optional wireless functionality extension. These features are achieved through the design of a highly scalable underlying EEG acquisition module and an FPGA central module that enables software-defined high-throughput expansion and high-speed data exchange between software and hardware. The paper presents two implementation cases that demonstrate the potential of the proposed system. The first case introduces a wearable wireless EEG system, enabling the deployment of effective and user-friendly steady-state visual evoked potential (SSVEP)-BCI applications in consumer-grade scenarios. The second case integrates an FPGA central module with multiple basic EEG acquisition modules to construct a high-throughput BCI system for cost-effective and real-time EEG data acquisition and processing. This configuration allows for flexible deployment in research and clinical applications, including attention index, SSVEP, motor imagery (MI), and emotion recognition. This combination further demonstrates the potential of scalable EEG systems and emphasizes the need for further integration or chipization. These implementations validate the feasibility of compact and efficient EEG devices and highlight the promising applications of scalable BCI system in various fields.

Sustainable Recycling of Perovskite Solar Cells: Green Solvent‐Based Recovery of ITO Substrates

ABSTRACTPerovskite solar cells (PSCs) emerge as a leading next‐generation photovoltaic (PV) technology, with power conversion efficiencies (PCEs) reaching 26.7% for single cells and 36.1% for hybrid tandem cells. As commercialization progresses, the inverted (p–i–n) structure of PSCs gains attention due to its enhanced thermal stability, lower moisture sensitivity, and reduced processing temperatures compared to the conventional (n–i–p) structure. However, sustainability concerns, particularly regarding production costs and end‐of‐life disposal, become increasingly critical. Recycling PSCs provides a viable solution to these challenges by recovering valuable indium tin oxide (ITO) substrates, which significantly impact material costs. Existing recycling methods for conventional PSCs often use toxic solvents like chlorobenzene (CB) and N,N‐dimethylformamide (DMF), posing environmental and health risks. This study introduces an eco‐friendly recycling process for ITO‐based inverted PSCs using acetone as a green solvent. The results show that recycled ITO substrates maintain their physical, electrical, and optical properties without significant degradation in PSC performance, even after multiple recycling cycles. This green solvent‐based approach not only preserves device efficiency but also supports future environmental regulations, highlighting its potential in promoting sustainable and cost‐effective PV technologies.

Ternary Compensation Enables High-sensitive Efficient Upconversion Device for NIR Visualization.

Beyond the crystalline photodiodes for infrared visualization, with the limitation of opacity and complex lithographic processes, organic upconversion device (UCD) have emerged as a potential alternative. In this research, a ternary compensation strategy is implemented in a non-fullerene-based active layer to reduce the dark current of the detector and enhance its detection performance, which enables high-sensitive efficient upconversion device for near-infrared light (NIR) visualization. The device achieves an infrared-to-visible upconversion efficiency of 16.68% when resolving the 980 nm infrared signal at a power density of 0.4 mW cm-2. In addition, by replacing the semitransparent matrix electrodes, a large-area (12.25 cm2) is further fabricated, lightweight (6.5g containing encapsulation), pixel-less (equivalent resolution 1270 ppi), and semitransparent (AVT ≈40%) UCD with microsecond response time. The fabricated UCD is demonstrated in pixel-less active infrared naked-eye visualization and infrared counter-surveillance, fostering the advancement of infrared visualization technology.

Piperazine‐Functionalized Arylene Diimides as Electron Transport Layers for High‐Efficiency and Stable Organic Solar Cells

AbstractIn organic solar cells (OSCs), electron transport layer (ETL) materials are typically designed with highly polar groups to lower the work function (WF) of the cathode and ensure solvent orthogonality. However, the increased surface energy associated with these polar groups results in significant hygroscopicity and poor interfacial contact with the active layer, posing a challenge for interlayer engineering that must balance device efficiency and stability. Herein, two novel arylene diimides (PDI‐P and NDI‐P) are developed with side chains that are end‐capped with piperazine groups, as opposed to the commonly used amine groups. As ETLs, these materials not only exhibit excellent electron conductivity but also effectively lower the WF of the silver cathode. Compared to the amine‐functionalized perylene diimide (PDI‐N), the piperazine‐functionalized perylene diimide (PDI‐P) exhibits reduced surface energy and hygroscopicity, resulting in improved wettability with the active layer and decreased moisture sensitivity. These characteristics contribute to enhanced interfacial contact and device stability. The PDI‐P ETL is compatible with various high‐performance electron acceptor materials, achieving high efficiencies across a wide thickness range of ≈7 to 30 nm, with a maximum efficiency of 19.8%. These findings highlight the great potential of PDI‐P as an ETL for high‐efficiency and stable OSCs.

Progress in the Stability of Small Molecule Acceptor-Based Organic Solar Cells.

Significant advancements in power conversion efficiency have been achieved in organic solar cells with small molecule acceptors. However, stability remains a primary challenge, impeding their widespread adoption in renewable energy applications. This review summarizes the degradation of different layers within the device structure in organic solar cells under varying conditions, including light, heat, moisture, and oxygen. For the photoactive layers, the chemical degradation pathways of polymer donors and small molecule acceptors are examined in detail, alongside the morphological stability of the bulk heterojunction structure, which plays a crucial role in device performance. The degradation mechanisms of commonly used anode and cathode interlayers and electrodes are addressed, as these layers significantly influence overall device efficiency and stability. Mitigation methods for the identified degradation mechanisms are provided in each section to offer practical insights for improving device longevity. Finally, an outlook presents the remaining challenges in achieving long-term stability, emphasizing research directions that require further investigation to enhance the reliability and performance of organic solar cells in real-world applications.

Ameliorating Device Efficiency of Perovskite Solar Cells via Low‐Cost Interfacial Modification between SnO2 and Perovskite Absorber

Ameliorating Device Efficiency of Perovskite Solar Cells via Low‐Cost Interfacial Modification between SnO₂ and Perovskite Absorber

Role of grain boundary passivation in the enhancement of efficiency of copper chalcogenides thin film photovoltaic devices: A schematic review

Photovoltaic devices are expected to display peak performance if fabricated with perfect single crystals. Since surfaces break the periodicity of a single crystal, there are regions of defects, which give rise to states inside the forbidden energy gap. In polycrystalline thin films, the main structural defect is the grain boundary. The presence of grain boundaries affects the optical absorption, carrier mobility and lifetime of the semiconductor. This review focuses on grain boundary passivation in thin film photovoltaic devices based on copper chalcogenides. Achieving enhanced performance in copper chalcogenide thin film Photovoltaic devices requires effective grain boundary passivation. This approach aims to mitigate the adverse effects of grain boundaries on the optoelectronic properties of the material, leading to improved efficiency and stability in Photovoltaic devices. The abstract discusses recent developments, methodologies and outcomes related to grain boundary passivation strategies, shedding light on their significance in advancing the performance of copper chalcogenide thin film Photovoltaic devices. The exploration of grain boundary passivation in this context contributes valuable insights to the ongoing efforts in optimizing the performance of thin film Photovoltaic technologies.

Large Spin Hall Efficiency and Current-Induced Magnetization Switching in Ferromagnetic Heusler Alloy Co2MnAl-Based Magnetic Trilayers.

The spin Hall efficiency (ξ) is a crucial parameter that evaluates the charge-to-spin conversion capability of a material, and thus materials with higher ξ are highly desirable in spin-orbittorque (SOT) devices. Recent studies have highlighted the use of ferromagnetic materials as robust spin sources, paving the way for the development of more efficient SOT devices. To accelerate this innovation, it is essential to pursue ferromagnetic materials of high ξ. Here the experimental observation of a large spin Hall efficiency is reported in ferromagnetic Heusler alloy Co2MnAl (CMA)-based magnetic trilayers. Utilizing the current-induced hysteresis loop shift technique, the spin Hall efficiency is determined to be 0.077 for the B2-phase and 0.029 for the disordered CMA. Notably, magnetization switching both with and without the application of an external auxiliary magnetic field were achieved in these trilayers. The enhancement of ξ is attributed to the formation of chemical ordering in CMA. These findings provide new avenues for the development of ferromagnet-based SOT devices.

NEIL: aN EfficIent cLuster-based device discovery for D2D communication in B5G

NEIL: aN EfficIent cLuster-based device discovery for D2D communication in B5G

Einstein frequency of individual chalcogen bonds in Cu(In,Ga)Se2 and Cu(In,Ga)S2: Indicator of diffusion property of Cu, In, and Ga atoms

Elucidating the characteristics of the Cu-Se, In-Se, and Ga-Se bonds in chalcopyrite-type Cu(In,Ga)Se2-based semiconductors can aid the design and fabrication of highly efficient thin-film photovoltaic devices. In this study, we used extended X-ray absorption fine structure (EXAFS) analyses to evaluate the characteristics of chemical bonds in Cu(In,Ga)Se2 and Cu(In,Ga)S2 powder samples at low temperatures (10–300 K). The temperature dependence of the structural and vibrational disorder (Debye–Waller factor) provides the Einstein temperature of an individual bond in Cu(In,Ga)Se2-based materials. The analyzed Einstein temperature, which is proportional to the Einstein frequency, increased in the order of Cu–Se(S) < In–Se(S) ≤ Ga–Se(S), and the S-containing bond had a higher Einstein temperature than the corresponding Se-containing one. We also analyzed the effect of the Ga/(Ga + In) ratio on the Einstein temperature of each chemical bond. The force constant of the oscillator (i.e., the bond) was determined from the Einstein frequency using the reduced mass of the constituent atoms. The obtained bond properties were found to correlate with the diffusion characteristics of the constituent atoms in CuInSe2-based solar cell materials.

Advancing all-polymer solar cells with solid additives

AbstractAll-polymer solar cells (all-PSCs) have attracted significant research attention in recent years, primarily due to their advantages of outstanding photo-thermal stability and excellent mechanical flexibility. However, all-PSCs typically exhibit complex morphologies during the film formation of blend films, primarily due to the tendency to become entangled in polymer chains, negatively impacting their fill factor (FF) and morphology stability. Therefore, the optimization of the morphology of the co-mingled heterojunction is crucial for improving device performance. Recent studies reveal that solid additives (SAs) can realize the excellent regulation of the molecular aggregation state, molecular packing, and domain size of the active layer, which not only improves the exciton dissociation, charge transport and collection process of the device but also ultimately realizes the enhancement of the device efficiency. Therefore, this review provides an in-depth insight into the different mechanisms of solid additives in all-PSCs, offering a comprehensive discussion on the research progress in optimizing the morphology and enhancing morphology stability. Finally, we present an outlook for the further structural modification strategies of solid additives towards better bulk morphology and stability of all-PSCs, paving the way for achieving excellent photo-thermal stability, superior mechanical flexibility, and high-efficiency all-PSCs.

Low-Power Design of Fully Digital BPSK Modulator and Demodulator Utilizing Nanoscale FinFET for Smart Implants

This study aims to create a high-speed, low-power data transmission solution for implantable medical devices based on cutting-edge FinFET technology. The work examines the application of Binary Phase Shift Keying (BPSK) modulation through a transmission gate design, which provides an optimal blend of low resistance, high-speed performance, and minimal power consumption. Additionally, the work includes the design of a sine-to-square wave converter and a modulating signal generator. FinFET is employed owing to its high switching speed, low power consumption, low leakage current, and excellent tolerance of short channel effects. The design exhibits a steady electric field at the source end, a high electrostatic potential, and an improved ON current at low work function values using Sentaurus TCAD simulations of a 20nm FinFET, allowing high-speed data modulation in smart implants. A nonoverlapping phase generator, a low-power, current-starved gated ring oscillator, a frequency divider utilizing a True Single Phase Clock D-Flip-flop, and an XOR gate serving as a pulse counter are all featured in the design of the BPSK demodulator. This work is significant for its ability to drastically reduce power consumption to 1.75μW while retaining high data transmission speeds, making it perfect for next-generation implantable medical devices. With a 0.9 V power supply, this FinFET-based BPSK modulator and demodulator achieve a far lower power consumption than conventional CMOS-based designs, which increases device longevity and efficiency in settings with limited resources.