Device Configuration Research Articles

Simultaneous resistance switching and rectifying effects in a single hybrid perovskite

AbstractHalide perovskites with naturally coupled electron‐ion dynamics hold great potential for nonvolatile memory applications. Self‐rectifying memristors are promising as they can avoid sneak currents and simplify device configuration. Here we report a self‐rectifying memristor firstly achieved in a single perovskite (NHCINH3)3PbI5 (abbreviated as (IFA)3PbI5), which is sandwiched by Ag and ITO electrodes as the simplest cell in a crossbar array device configuration. The iodide ions of (IFA)3PbI5 can be easily activated, of which the migration in the bulk contributes to the resistance hysteresis and the reaction with Ag at the interface contributes to the spontaneous formation of AgI. The perfect combination of n‐type AgI and p‐type (IFA)3PbI5 gives rise to the rectification function like a p–n diode. Such a self‐rectifying memristor exhibits the record‐low set power consumption and voltage. This work emphasizes that the multifunction of ions in perovskites can simplify the fabrication procedure, decrease the programming power, and increase the integration density of future memory devices.image

IMTIBOT: An Intelligent Mitigation Technique for IoT Botnets

The tremendous growth of the Internet of Things (IoT) has gained a lot of attention in the global market. The massive deployment of IoT is also inherent in various security vulnerabilities, which become easy targets for hackers. IoT botnets are one type of critical malware that degrades the performance of the IoT network and is difficult to detect by end-users. Although there are several traditional IoT botnet mitigation techniques such as access control, data encryption, and secured device configuration, these traditional mitigation techniques are difficult to apply due to normal traffic behavior, similar packet transmission, and the repetitive nature of IoT network traffic. Motivated by botnet obfuscation, this article proposes an intelligent mitigation technique for IoT botnets, named IMTIBoT. Using this technique, we harnessed the stacking of ensemble classifiers to build an intelligent system. This stacking classifier technique was tested using an experimental testbed of IoT nodes and sensors. This system achieved an accuracy of 0.984, with low latency.

Optimal configuration of passive flow control devices to reduce the aerodynamics drag of a tractor-trailer model

Aerodynamic drag plays an important role in heavy vehicles, especially when traveling at high speeds. In this context, the application of passive flow control devices emerges as a potential approach to reduce the aerodynamic drag of vehicles, leading to improvements in fuel efficiency and environmental pollution. Consequently, this study focuses on using cab side extenders and rear flaps to reduce the aerodynamic drag of a 1:8 small-scale simplified tractor-trailer model. The main parameters of this device configuration, including the length LR and deflection angle θG of the cab side extenders, the length LR and deflection angle θR of the rear flaps, are optimized to minimize the model aerodynamic drag coefficient. Numerical studies are performed using the Computational Fluid Dynamics method, with the steady k-ω SST and the unsteady DES turbulence model. The optimal solution is implemented based on a 30-level Latin Hypercube design of the experiment and a full quadratic regression response surface method. The obtained results show that a maximum reduction in the aerodynamic drag coefficient of the simplified tractor-trailer model by 20.8 % is achieved with an optimized configuration of control devices. The mechanism of aerodynamic drag reduction is also evaluated based on the analysis of flow fields around the vehicle model.

Recent Progress in Solar-Blind Photodetectors Based on Ultrawide Bandgap Semiconductors.

Ultrawide bandgap (UWBG) semiconductors, including Ga2O3, diamond, Al x Ga1-x N/AlN, featuring bandgaps greater than 4.4 eV, hold significant promise for solar-blind ultraviolet photodetection, with applications spanning in environmental monitoring, chemical/biological analysis, industrial processes, and military technologies. Over recent decades, substantial strides in synthesizing high-quality UWBG semiconductors have facilitated the development of diverse high-performance solar-blind photodetectors (SBPDs). This review comprehensively examines recent advancements in UWBG semiconductor-based SBPDs across various device architectures, encompassing photoconductors, metal-semiconductor-metal photodetectors, Schottky photodiodes, p-n (p-i-n) photodiodes, phototransistors, etc., with a systematic introduction and discussion of their operational principles. The current state of device performance for SBPDs employing these UWBG semiconductors is evaluated across different device configurations. Finally, this review outlines key challenges to be addressed, aiming to steer future research endeavors in this critical domain.

Approach to creation model of software-oriented communication network of the State Border Guard Service of Ukraine.

Enhancing the level of information resource protection of the State Border Guard Service of Ukraine, as a component of Ukraine's defense forces, is an important task, especially in times of war. An effective and reliable corporate network of the border agency becomes a key component for ensuring security, coordination, and responsiveness to both internal and external threats. One aspect of developing the information space is the development of the transport network of the State Border Guard Service. Analysis of existing technologies, identifying their advantages and disadvantages, allowed for the identification of Software-Defined Wide Area Networking technology as the one that best meets the conformity criteria defined by the experts of the Communication and Information Systems Management. This technology not only allows for optimizing network traffic and ensuring high-speed data transmission but also guarantees flexibility in network management and enhances security. For the State Border Guard Service, responsible for the security of the country's borders, the use of advanced Software-Defined Wide Area Networking technologies can be crucial for optimizing operations and ensuring the highest level of information security. The article focuses on developing a conceptual model for building the corporate network of the State Border Guard Service based on Software-Defined Wide Area Networking technology. The main goal of the research is to consider the possibility of implementing this technology in the context of its application by Ukraine's defense forces and to analyze its advantages and disadvantages. The research task was to study the technical aspects of implementing Software-Defined Wide Area Networking, namely: configuration of network devices, traffic management, security monitoring, and data protection. Cisco's Software-Defined Wide Area Networking has applied an optimal approach to network architecture, which separates the control plane from the data plane of all peripheral routers and implements all control functions in a centralized software controller called vSmart. Practical recommendations from the research allowed for ensuring continuous network service by rerouting around failures and potential causes of downtime.

Synergetic Triple Absorber Based High‐Efficiency Solar Cell Design

AbstractComputational analysis of triple absorber‐based solar cell structure is undertaken. This solar cell device configuration allows better utilization of the incident solar spectrum. Three different absorbers with a band gap in the range 1–1.5 eV are sandwiched between high‐doped p+ and n+ regions in descending order of electron affinity to form an energy‐matched multiple absorber device. A comprehensive analysis of key device parameters influencing performance, including band gap, conduction band alignment, interfacial defects, and thickness, is presented. The optimized triple absorber device shows beyond Shockley–Queisser limit (SQ limit) performance under the constraint of passivated interfaces with defect density below 1013 cm−2. Wide spectrum coverage leads to high short circuit current and an efficiency of 40.3%, which is higher than the SQ limit for single band gap solar cell.

Crystallization dynamics probed by transient resistance in phase change memory cells

Crystallization (set) time is a key bottleneck to achieve high-speed programming in phase change memory (PCM). Overcoming this limitation requires a deeper understanding of the solidification processes within nanoscale device configuration. This study explores crystallization dynamics in Ge2Sb2Te5 by measuring the transient resistance and power during the set process in confined PCM cells with nanosecond resolution. The transient resistance probes the phase, while the power can be used to evaluate temperature, thus uncovering details of the phase change dynamics. Our findings reveal a notable trend indicating that solidification from the melt results in faster crystallization compared with annealing the glassy state. Moreover, we observed notable differences in the solidification dynamics during set (crystallization) and reset (amorphization) pulses. Our nanosecond transient measurement methodology proves valuable in revealing crucial aspects of PCM crystallization dynamics, holding the potential to enable higher-speed programming.

Enhancement of photoresponse and photovoltaic properties in KBiFe2O5/BiFeO3 bilayer thin films

In this report, the performance of a new photovoltaic device configuration in which bilayer KBiFe2O5 (KBFO)/BiFeO3 (BFO) as absorber materials have been investigated and compared with the single active layer-based devices of BFO and KBFO. The obtained short-circuit current density of 58.81 μAcm−2, open-circuit voltage of 0.65 V, and power conversion efficiency of 0.014 % for the complete photovoltaic device glass/FTO/KBFO/BFO/Ag are comparatively higher than that of glass/FTO/BFO/Ag and glass/FTO/KBFO/Ag devices. It has been observed that the active bilayer KBFO/BFO shows switchable photoresponse with respect to positive and negative polarities. This work may offer the procedures for further optimizing the photo absorber layer, thereby improving the performances of multiferroic-based devices for ferroelectric photovoltaic applications.

Recent Advances in Electrochemical Cell Design for Concurrent Chemical Production and Electricity Generation

AbstractElectricity generation and chemical production are both critical cornerstone for modern society. Integrating electricity output and high value chemical production in an electrochemical system is highly attractive both environmentally and sustainably. In this review, we summarize the recent advances in the development of these multifunctional devices (electrocatalytic flow batteries) that could generate both electricity and high value chemicals through rational coupling of half‐electrode reactions, covering the basic principles, device configurations, and applications. We also discuss the current challenges and suggest potential research directions.

Active Passivation of Anion Vacancies in Antimony Selenide Film for Efficient Solar Cells.

Binary antimony selenide (Sb2Se3) is a promising inorganic light-harvesting material with high stability, nontoxicity, and wide light harvesting capability. In this photovoltaic material, it has been recognized that deep energy level defects with large carrier capture cross section, such as VSe (selenium vacancy), lead to serious open-circuit voltage (VOC) deficit and in turn limit the achievable power conversion efficiency (PCE) of Sb2Se3 solar cells. Understanding the nature of deep-level defects and establishing effective method to eliminate the defects are vital to improving VOC. In this study, a novel directed defect passivation strategy is proposed to suppress the formation of VSe and maintain the composition and morphology of Sb2Se3 film. In particular, through systematic study on the evolution of defect properties, the pathway of defect passivation reaction is revealed. Owing to the inhibition of defect-assisted recombination, the VOC increases, resulting in an improvement of PCE from 7.69% to 8.90%, which is the highest efficiency of Sb2Se3 solar cells prepared by thermal evaporation method with superstrate device configuration. This study proposes a new understanding of the nature of deep-level defects and enlightens the fabrication of high quality Sb2Se3 thin film for solar cell applications.

Emerging 2D Ferroelectric Devices for In-Sensor and In-Memory Computing.

The quantity of sensor nodes within current computing systems is rapidly increasing in tandem with the sensing data. The presence of a bottleneck in data transmission between the sensors, computing, and memory units obstructs the system's efficiency and speed. To minimize the latency of data transmission between units, novel in-memory and in-sensor computing architectures are proposed as alternatives to the conventional von Neumann architecture, aiming for data-intensive sensing and computing applications. The integration of 2D materials and 2D ferroelectric materials has been expected to build these novel sensing and computing architectures due to the dangling-bond-free surface, ultra-fast polarization flipping, and ultra-low power consumption of the 2D ferroelectrics. Here, the recent progress of 2D ferroelectric devices for in-sensing and in-memory neuromorphic computing is reviewed. Experimental and theoretical progresses on 2D ferroelectric devices, including passive ferroelectrics-integrated 2D devices and active ferroelectrics-integrated 2D devices, are reviewed followed by the integration of perception, memory, and computing application. Notably, 2D ferroelectric devices have been used to simulate synaptic weights, neuronal model functions, and neural networks for image processing. As an emerging device configuration, 2D ferroelectric devices have the potential to expand into the sensor-memory and computing integration application field, leading to new possibilities for modern electronics.

Device engineering of Sb2X3 antimony chalcogenide for loss analysis and strategies for maximizing photovoltaic efficiency

Antimony chalcogenide (Sb2X3; X=S, Se) is reportedly stable in ambient open-air, abundant, and shows composition-dependent absorption tunability. We simulated the Sb2X3 device utilizing the reported optical and electrical properties to analyze the performance limiting factors and the extent of achievable performance. Initially, we benchmarked the simulated device with the experimental reported device. The VOC-temperature and VOC-illumination characterization of the benchmarked device revealed the contact issue responsible for the VOC deficit. The suboptimal device configuration is a major performance-limiting factor. Contact optimization and conduction band offset optimisation have improved efficiency to 14.86% and 20.45% in Sb2S3 and Sb2Se3, from their experimentally reported values of 7.5% and 9.2% respectively. The optimization of trap-assisted Shockley Read Hall (SRH) recombination in bulk and interface has improved efficiency to 19.43% and 26.13% in Sb2S3 and Sb2Se3, respectively. When extrinsic factors are optimised, such as resistance losses (series resistance as high as 2 Ωcm2 and shunt resistance as low as 1000 Ωcm2), efficiency increased to 20.03% and 26.82% for Sb2S3 and Sb2Se3, respectively. Finally, with ideal intrinsic recombination parameters (radiative and Auger recombination), efficiency improved to theoretical limits (corresponding to their band gap). The study highlights the possibility of immediate gain upon contact passivation in Sb2S3 and Sb2Se3.

Biomechanical study of a biplanar double support screw (BDSF) technique based on Pauwels angle in femoral neck fractures: finite element analysis.

The objective of the present study is to conduct a comparative analysis of the biomechanical advantages and disadvantages associated with a biplanar double support screw (BDSF) internal fixation device. Two distinct femoral neck fracture models, one with a 30° angle and the other with a 70° angle, were created using a verified and effective finite element model. Accordingly, a total of eight groups of finite element models were utilized, each implanted with different configurations of fixation devices, including distal screw 150° BDSF, distal screw 165° BDSF, 3 CLS arranged in an inverted triangle configuration, and 4 CLS arranged in a "α" configuration. Subsequently, the displacement and distribution of Von Mises stress (VMS) in the femur and internal fixation device were assessed in each fracture group under an axial load of 2100N. At Pauwels 30° Angle, the femur with a 150°-BDSF orientation exhibited a maximum displacement of 3.17mm, while the femur with a 165°-BDSF orientation displayed a maximum displacement of 3.13mm. When compared with the femoral neck fracture model characterized by a Pauwels Angle of 70°, the shear force observed in the 70° model was significantly higher than that in the 30° model. Conversely, the stability of the 30° model was significantly superior to that of the 70° model. Furthermore, in the 70° model, the BDSF group exhibited a maximum femur displacement that was lower than both the 3CCS (3.46mm) and 4CCS (3.43mm) thresholds. The biomechanical properties of the BDSF internal fixation device are superior to the other two hollow screw internal fixation devices. Correspondingly, superior biomechanical outcomes can be achieved through the implementation of distal screw insertion at an angle of 165°. Thus, the BDSF internal fixation technique can be considered as a viable closed reduction internal fixation technique for managing femoral neck fractures at varying Pauwels angles.

Monolithically grown CSPbBr3 by chemical vapor deposition for Self-Powered photodetector

The high-quality monolithic growth of perovskite films with larger grains on any substrate is a challenging task due to the instability of morphology, carrier mobility and chemical stability. In this work, we demonstrated the strategy to grow CsPbBr3 films with micron-sized grains along the (002) surface by chemical vapor deposition. The structural and optical characterizations have shown that the as-grown CsPbBr3 thin films are compact and packed without pin holes and have excellent optical quality for use in high-performance optoelectronic devices. The planar photodetector with the device configuration Ag/CsPbBr3/Ag shows a high photoresponsivity of 506.32 A/W and a specific detectivity of 8.29 × 1012 Jones at an incident light illumination of 22.3 µW/cm2. On the other hand, the vertically stacked device with ITO/SnO2/CsPbBr3/CuSCN/Ag configuration exhibits a photoresponsivity of 10.13 A/W at 0.05 V bias and 96 mA/W under 0 V bias. Specifically, the response time of the device in planar geometry is 241/205 ms, while the vertically stacked device has a response time of 20.51/21 ms at 0.05 V bias and 20.51/30 ms at 0 V bias. The results provide a new strategy for the growth of high-quality perovskite thin films and their effective application for high-performance optoelectronic devices.

An extensive study on charge transport layers to design and optimization of high-efficiency lead-free Cs2PtI6-based double-perovskite solar cells: A numerical simulation approach

Perovskite materials are getting attention day by day due to their numerous optoelectronic properties. Lead-free perovskites are well-known for various applications in photovoltaic devices due to their non-toxicity which has no impacts on both the environment and health. Cs2PtI6, a lead-free halide perovskite, is renowned for its broad-spectrum light absorption and remarkably high absorption coefficient. Its stability under ambient conditions surpasses that of numerous other halide perovskites, rendering it exceptionally appealing for photovoltaic applications. The device configuration with FTO/ETL/Cs2PtI6/HTL/Au is used in this study where 4 different ETLs and 10 HTLs are used to investigate the best device configuration. The impact of different device parameters like thickness, acceptor density, donor density, and defect density are optimized to attain the best efficient device configuration. SCAPS-1D simulator is used to perform numerical analysis under light intensity of AM 1.5 light spectrum (100 mW/cm2). After the optimization of different device parameters, the device configured with FTO/SnS2/Cs2PtI6/MoTe2/Au shows the best performance among four devices where PCE is 32.98 %, VOC is 1.11 V, JSC is 33.19 mA/cm2, FF is 88.89 %. This suggested Cs2PtI6-based perovskite solar cells demonstrate superior performance compared to numerous lead perovskite-based solar cells, highlighting Cs2PtI6 as a promising alternative for photovoltaic applications while mitigating toxicity concerns.

A novel two-stage continuous capacitive deionization system with connected flow electrode and freestanding electrode

The desalination of seawater/wastewater utilizing flow-electrode capacitive deionization (FCDI) has received significant interest. However, challenges like the low electrical conductivity of flow electrode and excessive energy consumption have prevented the scaling up of desalination operations. To overcome these issues, this study introduces a new FCDI system termed the two-stage FCDI (TS-FCDI) system, in which desalination modules are equipped with freestanding and flow electrode. The TS-FCDI system offers a graded desalination module design that produces an average salt removal rate (ASRR) of 113 µg cm2·min−1. However, the TS-FCDI system requires substantially reduced infrastructure investment, device size, and energy expenses. Notably, the design allows for the simultaneous operation of freestanding and flow electrode and enables the transport of ions and charges in the electrode region. Experimental evidence from multiple device configurations (CDI, FCDI, and TS-FCDI) supports this claim. Notably, the TS-FCDI system shows about twice the desalination performance over FCDI, with approximately 50 h of single-cycle (SC) operation. This enhancement links the freestanding electrode with the flow electrode, enabling the device to be well-suited for practical applications. The continuous flow of electrode particles in contact with the freestanding electrode initiates secondary ion transport, merging two different types of electrodes to enhance the active space of the electrode, effectively improving ion adsorption performance. In summary, the results of this study indicate the potential of the TS-FCDI system as a suitable desalination technology for scaling up applications.

Top-Down Design Method of a Time Domain Accelerometer with Adjustable Resolution.

A top-down design methodology and implementation of a time domain sensor is presented in this paper. The acceleration resolution of the time domain sensor is equal to the time-measurement accuracy divided by the sensor sensitivity. Combined with the sensitivity formula, the acceleration resolution is proportional to the vibration amplitude, the time-measurement accuracy, and the third power of the resonant frequency. According to the available time-measurement accuracy and the desired acceleration resolution, the parameters including the vibration amplitude and the resonant frequency were theoretically calculated. The geometrical configuration of the time domain sensor device was designed based on the calculated parameters. Then, the designed device was fabricated based on a standard silicon-on-insulator process and a matched interface circuit was developed for the fabricated device. Experimental results demonstrated that the design methodology is effective and feasible. Moreover, the implemented sensor works well. In addition, the acceleration resolution can be tuned by adjusting the time-measurement accuracy and the vibration amplitude. All the reported results of this work can be expanded to other time domain inertial sensors, e.g., a gyroscope or tilt sensor.

A dual‐range Janus‐structure pressure sensor with broad detection range and high resolution combining triboelectricity and piezoelectricity

AbstractEnabling pressure sensors with high resolution and a broad detection range is of paramount importance yet challenging due to the limitations of each known sensing method. Overlying different sensing mechanisms to achieve complementary functions is a promising approach, but it often leads to increased device thickness, crosstalk signals and complex signal channel management. Herein, we present a dual‐functional conformable pressure sensor that adopts a Janus thin film layout, enabling simultaneous piezoelectric and triboelectric signal detection capabilities between just one electrode pair, showing a most compact device configuration. Notably, despite its thin thickness (~80 μm for a packaged device), it exhibits a broad‐range detection capability with high signal resolution and fast response time, demonstrating a distinct signal‐relay characteristic corresponding to piezoelectricity and triboelectricity. Despite the slimness and simple structure, it shows an impressive signal resolution of 0.93 V·kPa−1 in the range of 0.1–140 kPa and 0.05 V·kPa−1 in the range of 140–380 kPa. Moreover, the device fabrication can be combined with the kirigami method to improve fitting to joint surfaces. This work introduces an innovative paradigm for designing advanced pressure sensing mechanisms, enabling a single device that can meet diverse application scenarios through its simplicity, slim layout, conformable, and self‐powered characteristics to adapt to multiple scenarios.image

Exploring the impact of antimony trisulfide (Sb2S3) doping on the optoelectronic functionality of hybrid CH3NH3PbI3 perovskite layers and solar cells

In this study, we present the effect of doping with antimony trisulfide (Sb2S3) nanobare on the electrical, optical, structural, and morpholigcal properties of CH3NH3 PbI3 perovskite thin films. Doped with Sb2S3 nanobare, the thin coatings demonstrated an exceptionally high degree of purity, featuring a tetragonal phase within its single-phase structure. This allowed for the creation of (110) textured CH3NH3PbI3 films, which comprised micrometer-sized grains arranged in a vertical direction across the entire film thickness and featured high crystallinity. Additionally, the CH3NH3PbI3 perovskites films exhibited significant optical absorption at appropriate energy levels and exhibited a high gachin rate of photons. Substance doping methods that can optimize the morphology of the perovskite active layer with large granules are exceedingly desirable in order to reduce charge carrier recombination. The synthesis of perovskite films with dimensions on the order of microns can be achieved by incorporating a regulated quantity of Sb2S3 nanobare into the precursor solution. The incorporation of these textured CH3NH3PbI3:Sb2S3 nanobare films significantly enhanced the power conversion efficiency (PCE) of the perovskite solar cells. The solar cell device configuration utilized in this investigation is as follows: glass/FTO/TiO2/CH3NH3PbI3:Sb2S3 nanobars/spiro-OMeTAD/Au. By employing Sb2S3 nanobars at a concentration of 9 mg/mL, we successfully attained an exceptional power conversion efficiency of 15.87 %. The resulting values for these parameters include an open-circuit voltage VOC of 1.09 V, a short-circuit current density JSC of 21.15 mA/cm2, and a fill factor FF of 68.87 %.

Recent advances in multifunctional electrochromic devices

AbstractElectrochromic (EC) technology has been regarded as a promising energy‐saving technology in various applications, including smart windows, displays, thermal management, rear views, etc. Benefiting from the progress in electrochromic material synthesis, electrochromic electrode fabrication, and electrochromic device configuration design, the focus in electrochromic community has gradually shifted to multifunctional electrochromic devices (ECDs) in the era of Internet of Things. Multifunctional ECDs, such as electrochromic energy storage devices, multi‐color displays, deformable ECDs, smart windows, etc. have been showcased the ability to expand potential applications. In this review, the available device configurations, performance indexes and advanced characterization techniques for multifunctional ECDs are introduced and classified accordingly. The applications of multifunctional ECDs for energy storage, multicolor displays, deformable devices, self‐chargeable devices, smart windows, actuators, etc., are exemplified. The future development trends and perspectives of multifunctional ECDs are also overlooked. The aim of this review is to guide and inspire further efforts in the exploration of novel and advanced multifunctional ECDs.