Device Simulation Research Articles

Numerical design of non-toxic high-efficiency tandem solar cell with distinct hole transport materials

The metal-halide perovskite is at the forefront of photovoltaic research and has the potential to combine low manufacturing costs with excellent power conversion efficiency. In this study, a solar cell capacitance simulator was used to analyze the performance of a tandem solar cell in which MASnI3 was used as the lower cell active layer, and NaZn0.7Cu0.3Br3 was used as the upper cell active layer. The primary objective of this research is to search for a device structure with enhanced efficiency. Here, it is evaluated how absorber thickness, temperature, hole transport layer, defect density, and metal work function affect solar cell performance to reach this aim. After looking at the data for several different solar cell configurations, it is seen that indium tin oxide (ITO) / titanium dioxide (TiO2)/sodium zinc copper bromide (NaZn0.7Cu0.3Br3)/ methylammonium tin iodide (MASnI3) / copper oxide (CuO)/gold (Au) offers the best efficiency at 32.58 %, fill factor at 82.19 %, short circuit current density at 34.8389 mA/cm2, and open circuit voltage at 1.1375 Vs. Device simulations showed an optimal MASnI3 absorber thickness of about 1 µm. Finally, the simulation results reveal that the device's efficiency declines when the absorber's defect density and cell operation temperature rise. The device topologies are stable at around 300 Kelvin. Last but not least, any conductive material can be used as an anode if it has a work function that is more than or roughly equivalent to 5.10 eV.

Optimizing inorganic SnS/ZrS2 heterojunction solar cells: Numerical analysis and performance insights

The SnS and ZrS2 have emerged as promising photovoltaic materials. This paper gives the first numerical analysis of inorganic SnS/ZrS2 heterojunction solar cells using SCAPS-1D. The study focuses on the effect of several parameters, such as thickness, doping charge carrier concentration, and energy bandgap, on fundamental solar cell properties in both the window and active layers. Our findings show that a variety of parameters influence solar cell performance, including built-in voltage, minority charge carrier lifetime, depletion breadth, charge carrier collection length, photogenerated current, and recombination rate. The maximum efficiency (η) attained in our simulated devices was 32.13 %, with FF of 84.51 % and Voc of 0.796 V. To achieve this efficiency, particular SnS parameters were used, such as a band gap of 1.00 eV, thickness of 5.0 μm, and doping charge carrier concentration of 1020 cm−3. In ZrS2, characteristics such as a band gap of 1.2 eV, thickness of 0.2 μm, and doping charge carrier content optimized 1020 cm−3 contribute to the observed efficiency. Our simulation results indicate that inorganic SnS/ZrS2 heterojunction devices have potential for solar device production that is cost-effective, large-scale, and high-efficiency. High performance enables a new path toward clean energy.

Novel design of multi-point injection system for laboratory simulation of Martian low-pressure dust devils

The Martian surface is frequently traversed by dust devils, presenting formidable challenges to exploration missions and posing significant safety risks. Establishing a ground-based simulation device for low-pressure Martian dust devils is essential for conducting reliability testing and research on extreme environments relevant to Mars rovers. This study introduces a Martian dust devil simulator comprising a simulation cabin and multi-point injectors. This apparatus facilitates the investigation of velocity and pressure distribution patterns within the flow field under varying operational conditions by adjusting injector positions, inlet pressure, and internal pressure. The simulator's design allows it to replicate Martian dust devil velocity fluctuations from 0 to 50 m/s and pressure variations spanning 100–1500 Pa, thereby meeting crucial criteria for simulating Martian atmospheric conditions. Through computational fluid dynamics (CFD) simulation, we analyzed the characteristics of dust devils generated by the simulation device and scrutinized the flow field properties following the coupling of sand-dust particles with airflow. The observed dust devil flow field closely resembles the Vastitas Borealis vortex. Additionally, experimental research was conducted. Comparing experimental, simulated, and theoretical models revealed a high degree of consistency in the internal flow field characteristics of the simulated dust devils. The apparatus's versatility extends to simulating various dust devil morphologies, offering significant potential for conducting model experiments pertinent to Martian probes and facilitating future crewed Mars exploration endeavors.

Unveiling the Potential of Cs3Sb2ClxI9‐x‐Based Solar Cells for Efficient Indoor Light Harvesting: Numerical Simulation

AbstractLead‐free Perovskite‐inspired materials (PIM) have become the most promising candidate for indoor photovoltaics (IPV) because of their low toxicity and high performance. In this study, the potential of one of the lead‐free PIMs, Cesium antimony chloride iodide (Cs3Sb2ClxI9‐x), is explored for IPV devices. Recent experimental research work on a Cs3Sb2ClxI9‐x− based solar cell with a power conversion efficiency (PCE) of 3.7% is considered for the baseline model development. The device performance is further optimized by investigating 1) absorber thickness and defect density, 2) band alignment of Electron Transport Layer (ETL)/Absorber, ETL Doping concentration and absorber/ETL interface defect density, 3) band alignment of Hole Transport Layer (HTL)/Absorber, HTL Doping concentration, and absorber/HTL interface defect density, 4) work function of metal contacts, 5) series and shunt resistances. After device optimization, the simulated device under 1000 lux WLED is able to achieve Jsc, Voc, FF, and PCE of 1.8 mA cm−2, 1.46 V, 89.3%, and 45.05%, respectively. Further, an evaluation of the performance of the optimized device under various indoor light sources, including White Light Emitting Diode (WLED), halogen, and Compact Fluorescent Lamp (CFL), is conducted in order to assess its performance under widely utilized lighting conditions.

Adaptive meshing strategies for nanophotonics using a posteriori error estimation

As nanophotonic devices become increasingly complex, computer simulations of such devices are becoming ever more important. Unfortunately, computer simulations of nanophotonic devices are computationally expensive, especially if many simulations are necessary, e.g., when optimizing or inverse designing a device. Here we study adaptive mesh refinement for finite-element method simulations using an a posteriori error estimation method. We demonstrate that the use of adaptive meshing leads to faster convergence with lower memory footprint for complex three-dimensional nanophotonic structures. Nevertheless, one needs to be careful to avoid a mesh propagation effect for adaptive mesh refinement to be a successful strategy.

Effects of Photon Recycling and Luminescent Coupling in All‐Perovskite Tandem Solar Cells Assessed by Full Opto‐electronic Simulation

The impact of photon recycling (PR) and of luminescent coupling (LC) on the photovoltaic performance of all‐perovskite tandem solar cells is analyzed by the means of optical and full opto‐electronic device simulation. Optical processes are assessed using a comprehensive Green function formalism that considers wave optical effects also in emission. Starting from a consistent fit of experimental sub‐cell and tandem characteristics, the effects of re‐absorption are propagated from the optical limit to a situation with consideration of realistic charge transport across the entire tandem device. This also provides insight into the origin of performance losses due to sub‐cell and interconnection quality.

Projected performance of Si- and 2D-material-based SRAM circuits ranging from 16 nm to 1 nm technology nodes.

Researchers have been developing 2D materials (2DM) for electronics, which are widely considered a possible replacement for silicon in future technology. Two-dimensional transition metal dichalcogenides are the most promising among the different materials due to their electronic performance and relatively advanced development. Although field-effect transistors (FETs) based on 2D transition metal dichalcogenides have been found to outperform Si in ultrascaled devices, the comparison of 2DM-based and Si-based technologies at the circuit level is still missing. Here we compare 2DM- and Si FET-based static random-access memory (SRAM) circuits across various technology nodes from 16 nm to 1 nm and reveal that the 2DM-based SRAM exhibits superior performance in terms of stability, operating speed and energy efficiency when compared with Si SRAM. This study utilized technology computer-aided design to conduct device and circuit simulations, employing calibrated MoS2 nFETs and WSe2 pFETs. It incorporated layout design rules across various technology nodes to comprehensively analyse their SRAM functionality. The results show that, compared with three-dimensional structure Si transistors at 1 nm node, the planar 2DMFETs exhibited lower capacitance, leading to reduced cell read access time (-16%), reduced time to write (-72%) and lowered dynamic power (-60%). The study highlights the provisional benefits of using planar 2DM transistors to mitigate the performance degradation caused by reduced metal pitch and increased wire resistance in advanced nodes, potentially opening up exciting possibilities for high-performance and low-power circuit applications.

Study on trap sensitivity for single material gate and double material gate nano-ribbon FETs

In this work, the trap sensitivity of single material gate (SMG) and dual material gate (DMG) nano ribbon FETs (NRFETs) are reported using TCAD Sentaurus Device simulator. The trap sensitivity is extracted for Gaussian trap distribution of both acceptor and donor type traps. We have reported the trap sensitivity for the variation in trap concentration, energy peak position, work function of metal gate, and temperature for both the NRFETs. It is realized that trap sensitivity is greater and lesser than 100% for acceptor type trap in SMG and DMG NRFETs, respectively, whereas, such sensitivity is 147% and 123% for donor type trap concentration, respectively. Temperature also shows a significant variation in trap sensitivity for both the NRFETs. The increase in work function leads to the reduction in trap sensitivity for both NRFETs in existence of acceptor and donor trap charges. The maximum sensitivity in trap are 400% and 275% for SMG and DMG NRFETs, respectively, in presence of donor trap concentration. Moreover, the trap sensitivity is very insignificant at high gate bias for donor type trap concentration with wide variation in parameters.

Variation in chemical property of asphalt immersed in varying aqueous solutions and its leachate property

The pavement asphalt properties are susceptible to deterioration under environmental factors, and the deterioration product will affect its surrounding aqueous environment. For this reason, the idealized asphalt-aggregate mixture was treated with coupled temperature, ultraviolet and aqueous solutions based on self-made multifactorial coupled simulation device. Subsequently, the deterioration of asphalt chemical properties was analyzed by fourier transform infrared spectroscopy and saturate-aromatic-resin-asphaltene tests. Meanwhile, the effect of environmental factors on leachate properties was explored based on organic matter contents and chemical elements. Based on that, the grey correlation method was adopted to correlate asphalt chemical properties and leachate properties. The results clearly showed that environmental factors increased the sulfoxide and carbonyl group content of asphalt and transformed the chemical components within it into polar substances. The asphalt chemical properties were gradually improved when coupling ultraviolet with sodium carbonate, sodium chloride and distilled water sequentially. Compared to neutral solution, alkaline solution exacerbated the effect of asphalt precipitates on leachate properties. The environmental factors increased the organic matter contents and chemical elements of leachate with time. The interaction mechanism between asphalt and aqueous environment involved the deterioration of asphalt properties caused by the presence of water, as well as the release of precipitates from aged asphalt into surrounding aqueous environment.

Design and simulation of 2D Ruddlesden–Popper perovskite solar cells under LED illumination: Role of ETL and front contact band alignment

This paper focuses on the design and simulation of 2D Ruddlesden-Popper halide perovskite (RPHP) solar cells, emphasizing their optimization for indoor LED illumination conditions. The design process begins with the validation of physical models within the SCAPS device simulator, accomplished through careful calibration against experimental (MAMP)MAn−1PbnI3n+1 RPHP cell data. Subsequently, different values of <n> (with n = 1, 2, 3, and 4) are explored to study the impact of different band gap energies, aiming to identify the most suitable option for optimal efficiency across diverse LED color temperatures. By addressing both material-specific considerations and device architecture optimization, this study aims to establish a comprehensive framework for designing RPHP solar cells tailored for white LED illumination. Additionally, the simulation reveals that optimizing the electron affinity of the Electron Transport Layer (ETL) significantly impacts device performance, with efficiencies exceeding 25 %. Furthermore, the study discusses emerging trends such as ETL-free structures, which aim to address interface defects and enhance device performance. In addition, we analyze the impact of bulk trap density and thickness of the 2-D perovskite absorber on efficiency limitations. With an absorber thickness set at 800 nm, a marginal decrease in PCE is observed, for the ETL-free solar cell, from around 34 % to 32 % as the trap density ranges from 1011 to 1014 cm−3. In contrast, for the ETL-based structure with the same variations, PCE experiences a substantial decline, dropping from approximately 47 % to 37 %. While the ETL-free structure may exhibit a lower PCE compared to the ETL-based cell, its capacity to endure fluctuations in trap density offers a notable advantage.These efforts underscore the potential of 2D RPHP photovoltaic cells for indoor applications, presenting a pathway towards efficient, stable, and cost-effective photovoltaic technology suited for diverse lighting environments.

Design and Implementation of Electrochromic Smart Windows with Self-Driven Thermoelectric Power Generation.

Electrochromic smart windows can achieve controllable modulation of color and transmittance under an external electric field with active light and thermal control capabilities, which helps reduce energy consumption caused by building cooling and heating. However, electrochromic smart windows often rely on external power circuits, which greatly affects the independence and portability of smart windows. Based on this, an electrochromic smart window driven by temperature-difference power generation was designed and implemented. This smart window provides automatic and manual control of the reversible cycle of electrochromic glass from light blue to dark blue according to user requirements and changes in the surrounding environment, achieving adaptive adjustment of visual comfort and reducing energy consumption. The infrared radiation rejection (from 780 to 2500 nm) of the electrochromic smart window is as high as 77.3%, and its transmittance (from 380 to 780 nm) fluctuates between 39.2% and 56.4% with changes in working state. Furthermore, the temperature in the indoor simulation device with electrochromic glass as the window was 15 °C lower than that with ordinary glass as the window after heating with a 250 W Philips infrared lamp for ten minutes. After 2000 cycles of testing, the performance of the smart window was basically maintained at its initial values, and it has broad application prospects in buildings, vehicles, and high-speed rail systems.

The SpinBus architecture for scaling spin qubits with electron shuttling

Quantum processor architectures must enable scaling to large qubit numbers while providing two-dimensional qubit connectivity and exquisite operation fidelities. For microwave-controlled semiconductor spin qubits, dense arrays have made considerable progress, but are still limited in size by wiring fan-out and exhibit significant crosstalk between qubits. To overcome these limitations, we introduce the SpinBus architecture, which uses electron shuttling to connect qubits and features low operating frequencies and enhanced qubit coherence. Device simulations for all relevant operations in the Si/SiGe platform validate the feasibility with established semiconductor patterning technology and operation fidelities exceeding 99.9%. Control using room temperature instruments can plausibly support at least 144 qubits, but much larger numbers are conceivable with cryogenic control circuits. Building on the theoretical feasibility of high-fidelity spin-coherent electron shuttling as key enabling factor, the SpinBus architecture may be the basis for a spin-based quantum processor that meets the scalability requirements for practical quantum computing.

Enhanced efficiency of bifacial perovskite solar cells using computational study

The most rapidly expanding type of solar cells are the Perovskite Solar Cells (PSCs), because of its high device performance, ease of synthesis, high open-circuit voltage, and affordability. Despite these advantages, the development of perovskite-based solar cells continues to be impeded by the issues with perovskite stability and the utilization of the hazardous heavy element lead (Pb). The study emphasizes on the bifacial structure that maintains the conventional absorber layer and electron transport layer (ETL) in the optimized PSC structure. This study employs SCAPS software for device simulation to comprehensively analyze how various parameters affect the performance of solar cells. Additionally, doping concentration variation in both ETL and HTL are explored. The simulation reveals that changing device structure from monofacial to bifacial significantly influences PSC performance, demonstrating that optimizing individual layers effectively enhances overall solar cell performance. The optimized structure achieves impressive PSC performance metrics through parametric analysis, such as voltage (VOC) of 1.18 V, fill factor (FF) of 82.24%, current density (JSC) of 27.12 mA/cm2, power conversion efficiency (PCE) of 27.90% for an incident solar spectrum from the ETL side, and power conversion efficiency (PCE) of 19.86% for an incident solar spectrum from the HTL side, the calculated bifaciality factor (BF) for this structure is 71.18%.

21‐1: Invited Paper: Analysis of Capacitance Characteristics of Highly Efficient Blue OLEDs by Impedance Spectroscopy

Blue phosphorescent materials typically have larger capacitance compared with commercialized blue fluorescent OLEDs. To improve capacitance‐related image quality issues, we need to reduce capacitance of devices without sacrificing other device's properties such as efficiency, lifetime, and operating voltage. In this study, we analyzed devices with phosphor sensitized TADF (PST) emission devices by impedance spectroscopy and revealed that the capacitance is largely affected by giant surface potential (GSP) of consisting layers. The influence of GSP on capacitance is sensitively changed by not only GSP value but also the position of GSP layers in the device. We revealed the effect of GSP of HTL, BIL etc. and explained the mechanism underlying on this phenomena based on device simulation.

Determinants of Pilots’ Performance: Investigating Technology Trust and Situation Awareness

Simulation devices have been used in aviation training for decades, probably more than in other industries. Embarking on this study, we aim to understand the relationship between the information quality provided by the information system (simulator) to pilots with the effect on situation awareness and trust in technology. Also, we aim to understand how experienced pilots with total flight and simulator hours affect their situation awareness. Furthermore, the study introduces a novel theoretical model to explore how situation awareness and trust in technology jointly impact individual pilot performance. We used structured equation modeling within the data retrieved from a survey of 233 pilots. Our results show a large effect on individual pilot performance in a simulator between situation awareness and information quality. Also, the impact on trust in technology is supported with a large effect by information quality. There is a medium effect between information quality and situation awareness, with the experience shown by pilots having a small effect on situation awareness.

Monolithic all-perovskite tandem solar cells: advancing sustainable energy options

This paper discusses the results of a simulation-based study on lead-free perovskite tandem devices. Wide bandgap (1.8 eV) perovskite materials Cs2AgBi0.75Sb0.25Br6 as the top cell and narrow bandgap (1.3 eV) perovskite materials CsSnI3 as the bottom cell make up the simulated tandem cell device, respectively. The optimisation process involves individually fine-tuning both cells under standard solar radiation conditions of 100 W/m2. The tandem cells necessitate precise current matching between the two sub-cells. The current matching condition manifests at Jsc of 16 mA cm−2 when the top and bottom cells reach an optimised thickness of 700 nm and 65 nm, respectively. The optimised tandem cell achieves a 24.47% power conversion efficiency (PCE), a high Voc of 1.7278 V, and a high fill factor of 83.72%. Furthermore, tandem solar cells’ temperature dependence is examined in the 300 K to 400 K range, revealing that efficiency decreases with temperature due to a reduction in Jsc (short-circuit current). Notably, the current matching condition is primarily influenced by the top cell, which exhibits less variation than the bottom cell. This study paves the way for developing tandem solar cells made entirely of lead-free perovskites and presents a new approach for the experimental realisation of high-power conversion efficiency.

6‐1: Pragmatic low‐temperature polycrystalline thin‐film transistor technologies for high‐brightness and high‐temperature environments in AMOLED displays

This paper presents experimental and theoretical analysis of electrical characteristics for recent process‐based low‐temperature polysilicon (LTPS) thin‐film transistors (TFTs) in AMOED displays, focusing on high‐temperature and high‐luminance device characteristics. All off‐state current (Ioff) components in such conditions, which include gate‐induced drain leakage (GIDL), thermal generation, photo generation currents, are in detail analyzed. Exploring the effects of process technologies and device design in small‐size TFTs, in conjunction of reduced defect density‐of‐state (DOS) in the polycrystalline and its interface of gate oxide, we investigate optimal device and process design for reliable polycrystalline thin‐film transistor technologies in high‐brightness and high‐temperature situations. Numerical device simulations, supplemented by physics‐based analysis, confirm experimental results for our optimized device/process and gain diligent process/ design co‐optimization insights.

P‐251: Late‐News Poster: OLED Lifetime Optimization in Lower Current‐Density Region

The Organic Light Emitting Diode (OLED) lifetime property was investigated in the lower current‐density region. The OLED display is required for an equivalent long lifetime performance in higher and lower current‐density regions. It was clarified that hole accumulation at the interface between electron blocking layer (EBL) and emissive layer (EML) is important for the Blue OLED lifetime property at lower current densities. The device simulation showed that the appropriate EML hole barrier affects the carrier distribution.

Research on Metal Corrosion Behaviour of Indirect Air-cooled Circulating Water System

Abstract The indirect air cooling system of an air-cooled power plant consists of a surface condenser and an aluminum radiator. The radiator is usually made of 1050A pure aluminum, and the circulating water pipe connecting the radiator is made of Q235B carbon steel. This article simulates and controls typical water quality parameters such as dissolved oxygen and pH value in indirect air cooling systems using a self-designed simulation device, and studies the influence of various water quality parameters on material corrosion behavior in intercooled circulating water systems when aluminum and carbon steel coexist. The results indicate that factors such as dissolved oxygen, conductivity, pH value, temperature, and redox potential can all affect the corrosion rate of carbon steel and aluminum materials; The increase in temperature and dissolved oxygen leads to an increase in corrosion rate; The main way carbon steel corrodes the system is by consuming dissolved oxygen; The corrosion behaviour in the water circuit will lead to an overall decrease in pH value. In the presence of multiple metals, the influence of iron ions in the solution significantly increases the corrosion rate of aluminum.

Numerical investigation of the novel lead-free and eco-friendly InSnCl3-based inorganic perovskite solar cell using SCAPS-1D device simulation

Numerical investigation of the novel lead-free and eco-friendly InSnCl3-based inorganic perovskite solar cell using SCAPS-1D device simulation