Device Configuration Research Articles

Simulation of the fluid dynamic and thermal behavior of an experimental passive cooling system of photovoltaic panels

Solar energy capacity has increased significantly globally, with values above 800 GW produced by different systems. Among these, PVT panels can generate either electricity, heat, or both. As these systems present various issues associated with excessive temperature increases, cooling systems have been developed to control the temperature using fluids such as water. The article uses previous data from the Technologic Institute of Sonora, which analyzed various cooling device configurations and selected the best two options (B1 and B4) based on the panel efficiency. Using the boundary conditions and the predicted streamlines, a simulation was made in CFD programs, determining the correct parameters to replicate the system fluid dynamics. Several simulations were carried out using different turbulence models. After comparing the temperature contour diagram and the streamline, it was obtained that the k-ω turbulence model best describes the fluid's behavior. The transient analysis simulations allow us to determine that the B1 configuration delivers the best cooling effect as it presents the most homogeneous temperature profile. BIAS and RMSE were calculated to validate and contrast the results obtained experimentally, obtaining values of 0.8675 and 1.8981, respectively.

Parafilm Enabled Rapid and Scalable Delamination/Integration of Graphene for High‐Performance Capacitive Touch Sensor

The high electrical conductivity and bendability of graphene makes it versatile for flexible electronic sensor applications. The fabrication of such flexible sensors necessitates two important prerequisites: defect‐free transfer of graphene to a flexible substrate and creating appropriate patterns without altering graphene's inherent properties. Here, a potentially rapid and scalable method to delaminate graphene non‐destructively from a metal substrate by using flexible parafilm is reported. This method allows not only the scalable transfer of continuous graphene, but also the realization of graphene patterns on the parafilm substrate. Graphene on parafilm showed negligible doping effect with high room temperature carrier mobility exceeding 6 × 103 cm2 V−1 s−1 for a centimeter‐scale sample. Using parafilm as a substrate‐cum‐dielectric medium, a proof‐of‐concept capacitive touch sensor (CTS) arrays is demonstrated without the use of lithography, by simple cross‐assembling and mild heating. The graphene sensor thus realized in its simplistic device configuration had an enhanced sensitivity of 43% when touch and release cycles are performed on the device. The nearly non‐destructive and user‐friendly route for directly integrating graphene with a flexible substrate is expected to play a potential role in the design of graphene‐based flexible electronics.

Passive Control in a Continuous Beam under a Traveling Heavy Mass: Dynamic Response and Experimental Verification.

The motion of a heavy mass on a bridge span causes vibrations whose magnitude and frequency content depend on the mechanical properties of the structural system, including the magnitude of that mass and its speed of traverse. In order to limit vibrations that could potentially cause damage, a simple passive device configuration, namely the tuned mass damper (TMD), is introduced and its effect on the beam vibrations analyzed. Specifically, a TMD in the form of a single-degree-of-freedom (SDOF) unit comprising a mass and a spring is placed on the span to act as a secondary system for absorbing vibrations from the primary system, i.e., the bridge itself. A Lagrangian energy balance formulation is used to derive the governing equations of motion, followed by an analytical solution using the Laplace transform to investigate the transmission of vibratory energy between primary and secondary systems. Results are given in terms of time histories, Fourier spectra and spectrograms, where the influence of the TMD in reducing vibratory energy is demonstrated. The TMD is placed in the region where the beam's transverse motion is at a maximum, while its mechanical properties are sub-optimal, in the sense that there is no separate damper present and minimal damping is provided by the spring element itself. In parallel with the analysis, a series of experiments involving a simply supported model steel bridge span traversed by a heavy mass are conducted to first gauge the analytical solution and then to confirm the validity of the proposed passive scheme.

Copper doping effect in the back surface field layer of CdTe thin film solar cells

In this work, the Solar Cell Capacitance Simulator (SCAPS-1D) is employed to evaluate the characteristics of CdTe thin films with ZnTe as the Back Surface Field (BSF) layer and estimate the effective copper doping ratio at both the atomic scale and the device operational response perspective. The electrical characteristics of ZnTe, at varying levels of copper doping, were derived using density functional theory (DFT) by applying the generalized gradient approximation (GGA) and Hubbard U corrections (DFT+U). The performance of ZnTe with different Cu concentrations as a BSF layer was evaluated by analysing the values of four key parameters that are open circuit voltage (VOC), short circuit current density (JSC), fill factor (FF), and conversion efficiency (η). The results indicate that an increase in Cu concentration from 0% to 3%, 6%, 10%, and 12% resulted in a reduction of the energy band gap. Specifically, the energy band gap decreased from 2.24 eV to 2.10 eV, 1.98 eV, 1.92 eV, and 1.88 eV, respectively. Optimal Cu doping promotes the favourable shift in the valence band maxima (VBM) and formation of p + -ZnTe, lowering thermionic emission and improving carrier lifetime, which results in an improved ohmic contact, η = 18.73% for 10% of Cu content. Excessive doping in contrast degraded the overall device performance by forming an unmatched carrier band offset at the front interface with CdS, increasing the acceptor type defect and CdTe compensation rate. Overall, the findings suggest that incorporating a controlled level of Cu, which in this case is around 10%, promotes the efficiency and stability of the proposed CdTe device configuration to a certain extent.

A Star Network of Bipolar Memristive Devices Enables Sensing and Temporal Computing.

Temporal (race) computing schemes rely on temporal memories, where information is represented with the timing of signal edges. Standard digital circuit techniques can be used to capture the relative timing characteristics of signal edges. However, the properties of emerging device technologies could be particularly exploited for more efficient circuit implementations. Specifically, the collective dynamics of networks of memristive devices could be leveraged to facilitate time-domain computations in emerging memristive memories. To this end, this work studies the star interconnect configuration of bipolar memristive devices. Through circuit simulations using a behavioral model of voltage-controlled bipolar memristive devices, we demonstrated the suitability of such circuits in two different contexts, namely sensing and "rank-order" coding. We particularly analyzed the conditions that the employed memristive devices should meet to guarantee the expected operation of the circuit and the possible effects of device variability in the storage and the reproduction of the information in arriving signal edges. The simulation results in LTSpice validate the correct operation and confirm the promising application prospects of such simple circuit structures, which, we show, natively exist in the crossbar geometry. Therefore, the star interconnect configuration could be considered for temporal computations inside resistive memory (ReRAM) arrays.

A tri-modal tactile sensor based on porous ionic hydrogel for decoupled sensing of temperature and pressure

Developing simple device configurations to satisfy independent thermal and force sensing is critical for improving the recognition and manipulation capabilities of robotic hands on objects, but it remains a challenge. In this paper, through the composition adjustment of polyvinyl alcohol, KOH, nano-silica, glycerin, and the microporous structure design, the prepared ionic hydrogel sensor has promising comprehensive performance. It shows thermal sensitivity (−0.47 % °C−1, 0–20 °C; −0.24 % °C−1, 20–50 °C), pressure sensitivity (1 kPa−1, 0–300 kPa), pressure detection limit of 1 Pa, and mechanical durability (1000 compression fatigue cycles at 100 kPa). More importantly, the pressure-sensitive and thermal-sensitive properties hardly interfere with each other due to the ionic hydrogel network's synergy of excellent water retention, anti-freezing properties and heat insulation ability. The multifunctional tactile sensor is integrated into a robot hand to obtain force and thermal information of the measured object, and combined with machine learning algorithms to realize object recognition. The proposed sensing scheme has been applied to 6 kinds of fruit and vegetable classification tasks in a cold chain logistics scenario, showing a classification accuracy of 95 %.

Scaling of inverted PTB7-Th: PC71BM organic solar cell for large area organic photovoltaic modules

Abstract Performance studies of large area inverted organic photovoltaic (OPV) modules of configuration ITO/ZnO/PTB7-Th: PC71BM/MoO3/Ag are performed. At a laboratory of scale 0.06 cm2, this device configuration repeatedly demonstrates the power conversion efficiency (PCE) of ∼9%, which is within the range of PCE normally achieved for this configuration. The OPV modules with active area of 9.25 cm2 and 63 cm2 are fabricated employing spin coating techniques comprising a total area 25 cm2 (5 cm × 5 cm) and 144 cm2 (11 cm × 11 cm), respectively. The 25 cm2 module, composed of five cells connected in series show PCE of 3.256%, with short-circuit current (Jsc), open circuit voltage (Voc), and fill factor (FF), 3.210 mAcm−2, 3.20 V, and 31.719%. However, The 144 cm2 modules, composed of 10 cells connected in series show PCE 1.019, Jsc, Voc, and FF, 0.87 mAcm−2, 4.20 V, and 27.877%. The PCE dropped by 63.89% for modules of active area of 9.25 cm2 and 88.68% of modules of active area of 63 cm2. The PCE of the modules is decreased sharply due to loss in FF, and Jsc of the modules. These losses are exhibits due to quality of layer morphology, layer interfaces, and design of module. The PCE could be potentially improved up to the desired value by the further optimization of layer morphology, layer interfaces, design of module geometry, and film deposition/printing methods. The results showed that PTB7-Th: PC71BM is a splendid structure for future organic solar modules due to its high performance and compatibility with large area coatings.

Integrated polarization-free Bragg filters with subwavelength gratings for photonic sensing.

We present polarization-free Bragg filters having subwavelength gratings (SWGs) in the lateral cladding region. This Bragg design expands modal fields toward upper cladding, resulting in enhanced light interaction with sensing analytes. Two device configurations are proposed and examined, one with index-matched coupling between transverse electric (TE) and transverse magnetic (TM) modes and the other one with hybrid-mode (HM) coupling. Both configurations introduce a strong coupling between two orthogonal modes (either TE-TM or HM1-HM2) and rotate the polarization of the input wave through Bragg reflection. The arrangements of SWGs help to achieve two configurations with different orthogonal modes, while expanding modal profiles toward the upper cladding region. Our proposed SWG-assisted Bragg gratings with polarization independency eliminate the need for a polarization controller and effectively tailor the modal properties, enhancing the potential of integrated photonic sensing applications.

Key Factors Influencing the Operationalization and Effectiveness of Telemedicine Services in Henan Province, China: Cross-Sectional Analysis.

Telemedicine has demonstrated its potential in alleviating the unbalanced distribution of medical resources across different regions. Henan, a province in China with a population of approximately 100 million, is especially affected by a health care divide. The province has taken a proactive step by establishing a regional collaborative platform for telemedicine services provided by top-tier provincial hospitals. We aim to identify the key factors that influence the current operationalization and effectiveness of telemedicine services in Henan province. The insights gained from this study will serve as valuable references for enhancing the efficient operation of telemedicine platforms in low- and middle-income regions. We analyzed service reports from the performance management system of telemedicine services in Henan province throughout 2020. Using descriptive statistics and graphical methods, we examined key influencing factors, such as management competency; device configuration; and hospital capability, capacity, and service efficacy, across hospitals at 2 different tiers. In addition, we used generalized linear models and multiple linear regression models to identify key operational factors that significantly affect the service volume and efficacy of 2 major telemedicine services, namely teleconsultation and tele-education. Among the 89 tier 3 hospitals and 97 tier 2 hospitals connected to the collaborative telemedicine platform, 65 (73%) and 55 (57%), respectively, have established standardized management procedures for telemedicine services. As the primary delivery method for telemedicine services, 90% (80/89) of the tier 3 hospitals and 94% (91/97) of the tier 2 hospitals host videoconferencing consultations through professional hardware terminals rather than generic computers. Teleconsultation is the dominant service type, with an average annual service volume per institution of 173 (IQR 37-372) and 60 (IQR 14-271) teleconsultations for tier 3 and tier 2 hospitals, respectively. Key factors influencing the service volume at each hospital include available funding, management competency, the number of connected upper tiers, and the number of professional staff. After receiving teleconsultations from tier 3 (65/89, 73%) and tier 2 (61/97, 63%) hospitals, patients reported significant improvements in their medical conditions. In addition, we observed that service efficacy is positively influenced by management competency, financial incentives, the number of connected upper or lower tiers, and the involvement of participating medical professionals. Telemedicine has become increasingly popular in Henan province, with a notable focus on teleconsultation and tele-education services. Despite its popularity, many medical institutions, especially tier 2 hospitals, face challenges related to management competency. In addition to enhancing the effectiveness of existing telemedicine services, health care decision-makers in Henan province and other low- and middle-income regions should consider expanding the service categories, such as including remote emergency care and telesurgery, which have promise in addressing crucial health care needs in these regions.

In2S3 thin films with potential use as window layers in photovoltaic devices

In this study, we use the Haacke’s figure of Merit (FOMH) as a valuable parameter for determining suitable Indium Sulphide thin films among a set of samples processed with different deposition parameters, in order to use them as window layers in the usual configuration of photovoltaic devices. Two sets of In2S3 thin films were deposited by radiofrequency (RF) magnetron sputtering technique with an average thickness around 90 nm and using different deposition parameters. One set of samples was processed using different RF power in the range of 75–250 W at room temperature, the second set was obtained using different substrate temperatures 24 °C–350 °C keeping a constant RF power at 75 W. The FOMH consider optical and electrical properties of In2S3 thin films in order to evaluate the feasibility of the thin film to be used as a window layer in photovoltaics devices. The In2S3 thin films processed by RF-Sputtering were analyzed by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), Ultraviolet-Visible spectroscopy, Raman spectroscopy, x-ray diffraction (XRD) and four-probe method. The In2S3 thin films had a high optical transmittance of 84% and the energy band gap values of the films decreased from 2.48 to 2.38 with the increase in substrate temperature and deposition power. The estimated grain size decreasing from 65 to 45 nm as the RF power increased. Additionally, the crystallinity of the selected In2S3 thin films was analyzed by Raman and XRD and showing that the cubic and tetragonal β-In2S3 phases can coexist in the films. The In2S3 thin films showed resistivity vales around Higher values of FOMH were obtained for In2S3 thin films processed at 75 W, 250 W, 100 °C and 300 °C, therefore these layer are feasible candidates to be used as window layers in photovoltaic devices.

Optimization of preparation conditions and design of device configurations for Cu3AsS4 solar cells: a combined study of first-principles calculations and SCAPS-1D device simulations.

Former studies have investigated the band structure and optoelectronic properties of Cu3AsS4 and suggested that it is a promising photovoltaic (PV) absorber. However, its power conversion efficiency (PCE) from experiments is still unsatisfactory and detailed experimental optimization strategies are lacking. Here, combining first-principles calculations and SCAPS-1D device simulations, we have systematically studied the optoelectronic and defect properties of Cu3AsS4 to find the suitable growth conditions and have performed various device simulations by adjusting the constituent layers to optimize the device configuration of the Cu3AsS4 solar cell. Our results demonstrated that the defect and hole concentrations can be regulated to a reasonable range as the PV absorber in metal-rich and S-poor growth environments with a low growth temperature of 500 K. Owing to the large cliff-like conduction band offset between the traditional buffer layers CdS and Cu3AsS4, the open-circuit voltage loss is large and the corresponding PCE is low. The PCE can be improved by adopting the new buffer layers with low electron affinity. The corresponding n-type transparent electrode is further optimized. Finally, the solar cell with the configuration of FTO/WO3/Cu3AsS4/Mo is suggested and its PCE can reach an optimal value of 17.82%.

Location-Based Services for Indoor Environments: A User Experience Test

The location-based services (LBS) user experience in controlled indoor settings in this scientific research. The environments included a range of user demographics, device configurations, and ambient factors. According to our findings, customer satisfaction ratings ranged from 5 to 9 on a scale of 1 to 10, and the average location accuracy was 1.1 meters (±0.4 meters) across various interactions and locales. These conclusions were supported by qualitative comments, which expressed satisfaction with the effectiveness of the check-in procedures and the practicality of several LBS features. Negative reviews, on the other hand, revealed difficulties with positioning technology accuracy, highlighting the intricate interactions among variables influencing indoor location-based services user experiences. This study provides a solid scientific basis for indoor location-based services (LBS) optimization, highlighting the need of tackling practical issues to improve user contentment and the usefulness of such services in indoor environments.

Microwave engineered NiZrO3@GNP as efficient electrode material for energy storage applications.

Supercapacitors (SCs) have emerged as attractive energy storage devices due to their rapid charge/discharge rates, long cycle life, and high-power density. However, the development of innovative electrode materials to achieve high-performance remains crucial to meet future requirements in supercapacitor technology. In this work, we have explored the potential of a microwave-engineered NiZrO3@GNP composite as a promising electrode material for SCs. A microwave assisted hydrothermal approach was adopted for the fabrication of the NiZrO3@GNP nanocomposite. Structural and morphological investigations showed its structural richness and its chemical compositions. When applied as a SC electrode, this innovative combination exhibits battery-like behaviour with higher specific capacity (577.63 C g-1) with good cyclic stability, and good performance. We have assembled an asymmetric-type two-electrode SC device and analysed its electrochemical features. This NiZrO3@GNP device exhibits the specific capacity of 47 C g-1 with capacitance retention of 70% after 2000 charge-discharge cycles. Further research on optimizing the synthesis process and exploring different device configurations could pave the way for even higher-performance supercapacitors in the future.

Electrically driven hydrogel actuators: working principle, material design and applications

This review presents a comprehensive perspective on electrically driven hydrogel actuators, delving into their principles, molecular and composite designs, fabrication methodologies, device configurations, and their applications.

Comprehensive High-Voltage Parameter Extraction Strategy for BSIM-BULK HV Model

In this work, parameter extraction methodology for the BSIM industry standard high-voltage (HV) device compact model is presented. An extraction procedure covers entire range of operation, including weak inversion to strong inversion region, low and high drain biases, and multiple body biases with temperature effects. The extraction procedure is validated with experimental and numerical simulation data for several configurations of HV devices, including geometric variations.

Study on energy efficiency improvement strategy of photovoltaic-hybrid energy storage DC microgrid considering green energy saving concepts

Abstract In this paper, the development of microgrid technology is discussed in close connection with the growing energy demand and the real needs of energy structure adjustment in the context of the times. Guided by green energy saving, the research focuses on constructing a hybrid energy storage DC microgrid model, especially the integrated photovoltaic power generation model and the related control strategy and power characteristics. The article further adopts a fuzzy PID control strategy to optimize the energy efficiency configuration of hybrid energy storage devices in DC microgrids. By carefully analyzing and optimizing the energy storage system in the DC microgrid, remarkable results are obtained: the optimized capacitive charge states range from 0.1 to 0.9, indicating a significant fluctuation of capacitive charge states, but at the same time avoiding the phenomenon of light abandonment and ensuring the reliability of power supply. More notably, during the increase of SOC (state of the energy storage system) from 0.40 to 0.70, the system can perform mode transitions under continuous load changes. This point shows the effectiveness of the optimization method in improving the energy storage efficiency and enhancing the system performance of the DC microgrid. Overall, the optimization method proposed in this paper provides a practical energy storage optimization scheme for developing microgrids, which is of great practical significance in promoting the research and application of microgrid technology. This not only helps to improve the efficiency of energy use, but also is a crucial step to realize sustainable energy development.

On the issue of mathematical modeling of the interaction of phases in energy-packed heat and mass transfer devices

In this article given intensive development of theories of hydrodynamics and mass transfer in chemical technology devices has attracted much attention to the study of separated flows in contact devices of heat and mass transfer devices, as well as in energy devices with various values of operating parameters and configurations of contact devices (CD) operated in them. It should be noted that the most knowledge-intensive phenomena for modeling in CD are the turbulent nature of the gas phase flow and the separation of the boundary layer.

Numerical study of charge transport layers in inverted ternary organic photovoltaic cells

This study investigates the crucial role of charge transport layers in enhancing the performance of inverted organic photovoltaic cells (OPVs) through advanced numerical simulations using OghmaNano software. OPVs offer distinct advantages, including lightweight, flexibility, and potential cost-effectiveness compared to traditional silicon-based counterparts, making them pivotal for sustainable energy solutions. We evaluate the efficiency of inverted (iOPVs) employing binary (PM6:L8-BO) and ternary (PM6:D18:L8-BO) active layers, utilizing electron transport layers (ETLs) including ZnO, TiO2, and SnO2, and hole transport layers (HTLs) such as MoO3, PEDOT, and WO3. Results highlight ZnO with a 15 nm-thick layer combined with MoO3 HTL achieving an impressive efficiency of 18.89% in ternary devices, demonstrating the effectiveness of organic materials and ternary blends. The study demonstrates that TiO2 or SnO2 ETLs can compete effectively with ZnO ETLs, particularly when used at thinner thicknesses, and offers alternative fabrication methods. It suggests that employing thin ETL layers (15 ± 2 nm) could significantly enhance the performance of iOPV devices. Simulations are crucial for optimizing iOPV device configurations with thin ETL layers, enabling rapid prototyping and cost-effective exploration of material combinations and device architectures. These layers play a critical role in balancing charge carrier generation and transport efficiency, collectively maximizing device performance. Overall, the study underscores the pivotal role of simulations and optimized layer thicknesses in advancing OPV technology by refining manufacturing processes and accelerating the adoption of OPVs for sustainable energy solutions.

Enhanced comprehensive performance of carbon-based hole-transport-layer-free CsPbI2Br solar cells by a low-cost and stable long chain polymer

Hole-transport-layer (HTL)-free CsPbI2Br solar cells based on a carbon electrode have attracted widespread interest because they have a simple device configuration and good light and thermal stability, and moreover are independent of high-cost HTLs and precious metal electrodes.

Polypyrrole and activated carbon enriched MnCo2O4 ternary composite as efficient electrode material for hybrid supercapacitors.

The development of proficient electrode materials is one of the major tasks faced by modern techniques for energy storage. Integrating different materials with synergistic effects can be a valuable strategy for designing storage devices with high capacity and energy density. The spinel manganese cobaltite (MnCo2O4) is an outstanding candidate for supercapacitors owing to its remarkable pseudocapacitive behavior. However, it suffers from low electric conductivity and limited cyclic stability. To overcome its limitations, activated carbon with superior cyclic stability and polypyrrole with high electric conductivity can be incorporated in MnCo2O4. The synergistic effect of these components offers high capacitance, better conductivity, and superior cyclic performance to the ternary composite. Herein, the MnCo2O4/AC/PPY ternary composite has been synthesized by a facile approach. The optimized ternary composite (MAP-20) exhibited a wonderful capacitance of 945.77 F g-1 at five mV s-1 compared to pristine MnCo2O4 (254.98 F g-1). The real-time applicability of the optimized composite was tested with asymmetric device configuration. The asymmetric device with MAP-20 and MnO2/AC electrodes exhibited a wonderful Ed of 88.12 W h kg-1 (Pd ∼ 1.6 kW kg-1). The asymmetric device also exhibited excellent cyclic performance of 89.68% for 10 000 cycles. Further, the real-time applicability of the device was tested by illuminating a 39 red LED panel. Three asymmetric cells connected in series illuminated the panel for about 45 minutes. All these results suggest that the synergistic integration of various efficient electrode materials leads to enhanced electrochemical performance of supercapacitors.