Device Configuration Research Articles

Decoding the High Efficiency of Cs₂SnI₆ Perovskite Solar Cells: A Comprehensive Study Through First‐Principles Calculations and SCAPS Modeling

AbstractCs₂SnI₆ has emerged as a stable and environmentally friendly replacement for lead (Pb)‐based perovskite solar cells (PSCs) due to its air stability, attributed to the Sn⁴⁺ oxidation state, and non‐toxic composition (lead‐free). A key benefit of using Cs₂SnI₆ as an absorber layer is that it enables the elimination of hole transport layers (HTLs) in some device architectures; however, PSCs with HTLs generally outperform those without HTL. Here, the structural, electronic, and optical properties of Cs₂SnI₆ are investigated using first‐principles calculations, and photovoltaic effects by using SCAPS‐1D simulation software. Nine different device configurations have been investigated by combining three electron transport layers (ETLs) with three HTLs to optimize device performance. The impact of HTL thickness, ETL thickness, absorber layer thickness, and operating temperature are studied on the solar cell's efficiency. The optimized PSC demonstrates a fill factor (FF) of 84.683%, a power conversion efficiency (PCE) of 24.0%, the short circuit current density JSC of 28.433 mA cm−2, the open circuit voltage VOC of 0.998 V, and a quantum efficiency of 99.866%, with optimal operating conditions at 300 K.

Advances in Photonic Materials and Integrated Devices for Smart and Digital Healthcare: Bridging the Gap Between Materials and Systems.

Recent advances in developing photonic technologies using various materials offer enhanced biosensing, therapeutic intervention, and non-invasive imaging in healthcare. Here, this article summarizes significant technological advancements in materials, photonic devices, and bio-interfaced systems, which demonstrate successful applications for impacting human healthcare via improved therapies, advanced diagnostics, and on-skin health monitoring. The details of required materials, necessary properties, and device configurations are described for next-generation healthcare systems, followed by an explanation of the working principles of light-based therapeutics and diagnostics. Next, this paper shares the recent examples of integrated photonic systems focusing on translation and immediate applications for clinical studies. In addition, the limitations of existing materials and devices and future directions for smart photonic systems are discussed. Collectively, this review article summarizes the recent focus and trends of technological advancements in developing new nanomaterials, light delivery methods, system designs, mechanical structures, material functionalization, and integrated photonic systems to advance human healthcare and digital healthcare.

Epitaxial growth of transition metal nitrides by reactive sputtering

Implementing transition metal nitride (TM-nitride) layers by epitaxy into group-III nitride semiconductor layer structures may solve substantial persisting problems for electronic and optoelectronic device configurations and subsequently enable new device classes in the favorable nitride semiconductor family. As a prominent example, the integration of the group-III-transition metal nitride AlScN enabled an improved performance of GaN based transistor structures due to stronger polarization fields as has been recently demonstrated. For other transition metal nitrides (TMNs) and their alloys with group-III nitrides a range of other interesting properties is expected to enable novel devices and applications. We investigated the compatibility of TM-nitride layers with the growth of GaN-based structures on silicon substrates. As we show TiN layers are compatible and particularly suited as highly conducting, metallic-like buffer layer enabling true vertical conduction without elaborate backside processing. Also, we demonstrate epitaxial growth of alloys based on ScN and AlN as well as of HfN layers on Si(111) substrates by reactive sputtering using high purity gases and targets. Particularly, we analyzed the crystal structure and the quality of Sc-rich AlxSc1-xN. For HfN layers, we find a unique impact on the growth polarity of MOVPE-grown GaN layers on Si(111) which changes to N-polar growth. This represents a simple and technologically scalable approach for N-polar GaN-based layers on Si substrates.

Exploring Moiré Superlattices and Memristive Switching in Non-van der Waals Twisted Bilayer Bi2O2Se.

The discovery of moiré physics in two-dimensional (2D) materials has opened new avenues for exploring unique physical and chemical properties induced by intralayer/interlayer interactions. This study reports the experimental observation of moiré patterns in 2D bismuth oxyselenide (Bi2O2Se) nanosheets grown through one-pot chemical reaction methods and a sonication-assisted layer separations technique. Our findings demonstrate that these moiré patterns result from the angular stacking of the nanosheets at various twist angles, leading to the formation of moiré superlattices (MSLs) with distinct periodicities. The presence of these superlattices was confirmed using transmission electron microscopy (TEM) images. The observation of moiré patterns in 2D Bi2O2Se nanosheets highlights the potential of tuning the band structures of the non-van der Waals material and thus unlocking new material properties through precise control of intralayer/interlayer interactions. Furthermore, the stacked 2D Bi2O2Se nanosheets show interesting memristive switching characteristics, presenting a promising candidate for artificial synapses and neuromorphic computing. Traditional memristors typically utilize a vertical metal-insulator-metal (MIM) structure, which relies on the formation of conductive filaments for resistive switching (RS). This configuration, however, often results in abrupt switching during various cycles and significant variation from device to device. Herein, defective BOSe moiré material exhibits a nonfilamentary RS switching characteristic in a two-terminal lateral device configuration. This design reveals an RS mechanism driven by the modulation of the Schottky barrier height (SBH) due to the movement of Se vacancies (VSe) under an external electric field. The fabricated device exhibits excellent RS behavior, achieving an RS ratio of ∼20 with a high degree of control and consistency across multiple cycles and from device to device. Interestingly, the device shows a stable negative differential resistance effect in the high-voltage region due to the carrier trapping process. Finally, we studied the stability of the MSL in BOSe through TEM imaging and electrical characterization on different device configurations to evaluate the repeatability of the switching characteristics.

Unassisted photoelectrochemical CO2 reduction by employing III–V photoelectrode with 15% solar‐to‐fuel efficiency

AbstractSolar‐driven carbon dioxide reduction reaction (CO2RR) provides an opportunity to produce value‐added chemical feedstocks and fuels. However, achieving efficient and stable photoelectrochemical (PEC) CO2RR into selective products is challenging owing to the difficulties associated with the optical and the electrical configuration of PEC devices and electrocatalyst properties. Herein, we construct an efficient, concentrated sunlight‐driven CO2RR setup consisting of InGaP/GaAs/Ge triple‐junction cell as a photoanode and oxide‐derived Au (Ox‐Au) as a cathode to perform the unassisted PEC CO2RR. Under one‐sun illumination, a maximum operating current density of 11.5 mA cm–2 with an impressive Faradaic efficiency (FE) of ~98% is achieved for carbon monoxide (CO) production, leading to a solar‐to‐fuel conversion efficiency of ~15%. Under concentrated intensity of 10 sun, the photoanode records a maximum current density of ~124 mA cm–2 and maintains ~60% of FE for CO production. The results demonstrate crucial advancements in using III–V based photoanodes for concentrated PEC CO2RR.

Significant Radiation Reduction Using Cloud-Based AI Imaging in Manually Matched Cohort of Complex Aneurysm Repair.

Cloud-based, surgical augmented intelligence (Cydar Medical, Cambridge, UK) can be used for surgical planning and intraoperative imaging guidance during complex endovascular aortic procedures. We aim to evaluate radiation exposure, operative safety metrics, and post-operative renal outcomes following implementation of Cydar imaging guidance using a manually matched cohort of aortic procedures. We retrospectively reviewed our prospectively maintained database of endovascular aortic cases. Patients repaired using Cydar imaging were matched to patients who underwent a similar procedure without using Cydar. Matching was performed manually on a 1:1 basis using anatomy, device configuration, number of branches/fenestrations, and adjunctive procedures including in-situ laser fenestration. Radiation, contrast use, and other operative metrics were compared. Pre- and post-operative maximum creatinine was compared to assess for acute kidney injury (AKI) based on RIFLE Criteria. 100 patients from 2012-2023 were identified: 50 cases (38 FEVAR, 2 TEVAR, 3 octopus-type TAAA repair, 7 EVAR) where Cydar imaging was used, with suitable matches to 50 non-Cydar cases. Baseline characteristics including BMI did not differ significantly between the two groups (27.8 ± 5.6 vs. 26.7 ± 6.1; P=0.31). Radiation dose was significantly lower in the Cydar group (2529 ± 2256 vs 3676 ± 2976 mGy; P<0.03 Figure 1), despite there being no difference in fluoroscopy time (51 ± 29.4 vs 58 ± 37.2 min; P = 0.37). Contrast volume (94 ± 37.4 vs 93 ± 43.9 mL; P = 0.73), estimated blood loss (169 ± 223 vs 193 ± 222 mL; P = 0.97), and procedure time (154 ± 78 vs 165 ± 89.1 min) did not differ significantly. Additionally, Cydar vs non-Cydar patients did not show a significant difference between pre- and post-creatinine changes (0.13 +/- 0.08 vs 0.05 +/- 0.07; P=0.34). Only one patient in the non-Cydar group met RIFLE criteria for AKI post-operatively. The use of cloud-based augmented intelligence imaging was associated with a significant reduction in radiation dose in a cohort of matched aortic procedures but did not appear to affect other parameters or renal function. Even with advanced imaging, surgeons should remain conscientious about radiation safety and administration of nephrotoxic contrast agents.

Theoretical estimation to double the performance of perovskite solar cells using a graded absorber layer

This article presents a SCAPS-1D theoretical model to enhance the efficiency of single-junction perovskite solar cell by applying an absorber grading scheme to an existing device configuration. The optimized graded structure achieved nearly a 95% efficiency enhancement.

Managing Network Devices Configuration, Golden Configuration, and Network Device Compliance

Managing Network Devices Configuration, Golden Configuration, and Network Device Compliance

Automating Network Device Configuration and Compliance Enforcement

Automating Network Device Configuration and Compliance Enforcement

Thermally Stable Anthracene-Based 2D/3D Heterostructures for Perovskite Solar Cells.

Bulky organic cations are used in perovskite solar cells as a protective barrier against moisture, oxygen, and ion diffusion. However, bulky cations can introduce thermal instabilities by reacting with the near-surface of the 3D perovskite forming low-dimensional phases, including 2D perovskites, and by diffusing away from the surface into the film. This study explores the thermal stability of Cs0.09FA0.91PbI3 3D perovskite surfaces treated with two anthracene salts─anthracen-1-ylmethylammonium iodide (AMAI) and 2-(anthracen-1-yl)ethylammonium iodide (AEAI)─and compares them with the widely used phenethylammonium iodide (PEAI). The steric hindrance of AMAI limits the interaction of its NH3+ head with the perovskite lattice, relative to what is seen with AEAI and PEAI. As a result, AMAI requires more thermal energy to convert the 3D perovskite surface to a 2D perovskite. Annealing of perovskite surfaces treated with the iodide salts results in decreased power conversion efficiencies (PCEs) for PEAI and AEAI, while a PCE enhancement is observed for AMAI. Importantly, AMAI-treated devices show enhanced stability upon annealing of the film and a 100% yield of working pixels after a high-temperature stability test at 85 °C, representing the most reliable device configuration among all those studied in this work. These results reveal the potential of AMAI as a scalable surface treatment.

Effect of absorbing layer thickness on efficiency solar cells multijunctions vertical based CIGS Using SILVACO TCAD

In this study, we performed numerical simulations using SILVACO-TICAD to analyse microelectronic and photonic structures and identify the optimal device configuration between multi-junction tandem and vertical multi-junction solar cells. We focused on thin-film CIGS (Copper Indium Gallium Selenide) solar cells under normalized conditions (AM1.5G, 0.1 spectral irradiance, and 300 K). The vertical tandem structure analysed consists of three junctions. Multi-junction solar cells offer higher efficiencies than single-junction cells. By combining CGS (Copper Gallium Selenide) with CIGS, about a 10% efficiency improvement is achieved over a vertical multi-junction (Gover A,1974) CIGS-only solar cell. The optimized vertical multi-junction structure showed the following photovoltaic parameters: **short-circuit current density (Jsc) = 32.42 mA/cm², open-circuit voltage (Voc) = 2.52 V, and a conversion efficiency of 34.68%**. This study highlights the potential of multi-junction solar cells, especially when combining different materials, to achieve significant performance improvements over traditional single-junction configurations.

Kinetics of Volatile and Nonvolatile Halide Perovskite Devices: The Conductance-Activated Quasi-Linear Memristor (CALM) Model.

Memristors stand out as promising components in the landscape of memory and computing. Memristors are generally defined by a conductance mechanism containing a state variable that imparts a memory effect. The current-voltage cycling causes transitions of conductance, which are determined by different physical mechanisms, such as the formation of conducting filaments in an insulating surrounding. Here, we provide a unified description of the set and reset processes using a conductance-activated quasi-linear memristor (CALM) model with a unique voltage-dependent relaxation time of the memory variable. We focus on halide perovskite memristors and their intersection with neuroscience-inspired computing. We show that the modeling approach adeptly replicates the experimental traits of both volatile and nonvolatile memristors. Its versatility extends across various device materials and configurations, as W/SiGe/a-Si/Ag, Si/SiO2/Ag, and SrRuO3/Cr-SrZrO3/Au memristors, capturing nuanced behaviors such as scan rate and upper vertex dependence. The model also describes the response to sequences of voltage pulses that cause synaptic potentiation effects. This model is a potent tool for comprehending and probing the dynamical response of memristors by indicating the relaxation properties that control observable responses.

Numerical Investigation and Device Architecture Optimization of Sb2Se3 Thin-Film Solar Cells Using SCAPS-1D.

Antimony selenide (Sb2Se3) shows promise for photovoltaics due to its favorable properties and low toxicity. However, current Sb2Se3 solar cells exhibit efficiencies significantly below their theoretical limits, primarily due to interface recombination and non-optimal device architectures. This study presents a comprehensive numerical investigation of Sb2Se3 thin-film solar cells using SCAPS-1D simulation software, focusing on device architecture optimization and interface engineering. We systematically analyzed device configurations (substrate and superstrate), hole-transport layer (HTL) materials (including NiOx, CZTS, Cu2O, CuO, CuI, CuSCN, CZ-TA, and Spiro-OMeTAD), layer thicknesses, carrier densities, and resistance effects. The substrate configuration with molybdenum back contact demonstrated superior performance compared with the superstrate design, primarily due to favorable energy band alignment at the Mo/Sb2Se3 interface. Among the investigated HTL materials, Cu2O exhibited optimal performance with minimal valence-band offset, achieving maximum efficiency at 0.06 μm thickness. Device optimization revealed critical parameters: series resistance should be minimized to 0-5 Ω-cm2 while maintaining shunt resistance above 2000 Ω-cm2. The optimized Mo/Cu2O(0.06 μm)/Sb2Se3/CdS/i-ZnO/ITO/Al structure achieved a remarkable power conversion efficiency (PCE) of 21.68%, representing a significant improvement from 14.23% in conventional cells without HTL. This study provides crucial insights for the practical development of high-efficiency Sb2Se3 solar cells, demonstrating the significant impact of device architecture optimization and interface engineering on overall performance.

Multifunctional Optimization of MXene for Enhanced Comprehensive Performance of Crystal Silicon-MXene Back-Heterojunction Solar Cells.

Enhancing the cost-performance ratio is a fundamental objective for the advancement of the photovoltaic sector. In this context, the development of innovative solar cells that offer a straightforward device configuration but high performance is arguably the most crucial element. Herein, an undoped back-heterojunction crystalline silicon (c-Si) solar cell is endeavored to be crafted by simply drop-casting a Ti3C2Tx MXene ethanol colloidal solution onto the backside of an n-type c-Si (n-Si) wafer. Leveraging the good electrical property and stability, as well as the adjustable work function of MXene treated by europium trifluoromethanesulfonate (Eu(OTF)3), the elementary Ag/ZnO/n-Si/MXene/Ag solar cell delivers an impressive power conversion efficiency (PCE) of 12.5%. Moreover, the deposition of a SiO2 passivation layer through a simple self-developed electrochemical method increases the PCE further to 13.5% by ameliorating the interfacial contact between MXene and n-Si. Moreover, this unencapsulated solar cell exhibits improved stability, compared to the control device without Eu(OTF)3 treatment and SiO2 passivation.

Enhanced supercapacitor performance and hydrogen evolution reaction using Nb2CTx MXene-integrated HKUST-1 MOF

Abstract This work aims to investigate how HKUST-1 metal-organic framework (MOF) and Nb2CTx MXene operate in concert to improve the catalytic activity in the hydrogen evolution reaction (HER) and the effectiveness of supercapacitors. While HKUST-1 offers a very porous structure that is favorable for charge storage, Nb2CTx serves as both a conductive substrate and a catalytic site for HER. This combination leads to better charge transfer channels and increased electroactive sites, which ultimately results in higher HER efficiency (shown by a notably lower Tafel slope of 52.42 mV/dec). In configurations of two and three electrodes, a specific capacity of 2168 C/g at a current density of 1.0 A/g is demonstrated by HKUST-1/Nb2CTx Moreover, the theHKUST-1/Nb2CTx combination, in particular the HKUST-1/Nb2CTx//AC composite, shows remarkable stability; after 1000 cycles, they still retain 95 % of their capacity and achieve 97% coulombic efficiency. The HKUST-1/Nb2CTx decorated electrode exhibited energy and power density, reaching approximately 89 Wh/kg and 938 W/kg in two-electrode (real device) configurations. These results highlight the HKUST-1/Nb2CTx composite excellent potential in energy conversion and storage applications.

Hierarchically Promoted Light Harvesting and Management in Photothermal Solar Steam Generation.

Solar steam generation (SSG) presents a promising approach to addressing the global water crisis. Central to SSG is solar photothermal conversion that requires efficient light harvesting and management. Hierarchical structures with multi-scale light management are therefore crucial for SSG. At the molecular and sub-nanoscale levels, materials are fine-tuned for broadband light absorption. Advancing to the nano- and microscale, structures are tailored to enhance light harvesting through internal reflections, scattering, and diverse confinement effects. At the macroscopic level, light capture is optimized through rationally designed device geometries, configurations, and arrangements of solar absorber materials. While the performance of SSG relies on various factors including heat transport, physicochemical interactions at the water/air and material/water interfaces, salt dynamics, etc., efficient light capture and utilization holds a predominant role because sunlight is the sole energy source. This review focuses on the critical, yet often underestimated, role of hierarchical light harvesting/management at different dimensional scales in SSG. By correlating light management with the structure-property relationships, the recent advances in SSG are discussed, shedding light on the current challenges and possible future trends and opportunities in this domain.

A computational analysis to enhance performance of CIGS solar cells using back surface field and ZnSe buffer layer approach

Abstract This study aims to enhance copper indium gallium selenide (CIGS) solar cell efficiency while minimizing environmental impact by replacing the toxic CdS buffer layer with a ZnSe buffer layer. The CIGS chalcogenide semiconductor is a promising solar cell absorber material but has faced challenges related to defect-free manufacturing, misaligned buffer layers, and device configuration. Cuprous oxide (Cu2O) and zinc selenide (ZnSe), an inexpensive, eco-friendly, and widely available material, are suggested as a back surface field layer and buffer layer to enhance device performance. This paper proposes a new cadmium-free structure (Al/ZnO:Al/ZnO/ZnSe/CIGS/Cu2O/Ni) to enhance the efficiency of CIGS heterojunction solar cells by reducing charge carrier recombination losses. We utilized solar cell capacitance simulator (SCAPS-1D) to simulate photovoltaic (PV) performance and examined the impacts of electron affinity, absorber thickness, interface defect density, operating temperature, radiative recombination coefficient (RRC), Mott–Schottky analysis, parasitic resistance, and quantum efficiency on PV characteristics. Optimization and choosing a suitable buffer and passivation layer gives the device efficiency of 31.13%, followed by V OC (0.92 V), J SC (40.40 mA cm−2), and FF (83.34%) for the proposed structure. The RRC found to be 10−13 cm3 s−1 and the parasitic resistance of the solar cell are in good agreement for fabricating high-efficiency solar cells. These findings suggest that CIGS-based heterojunction solar cells represent a cutting-edge method for achieving high-efficiency solar cells that outperform earlier designs.

Electrical Control of Electroluminescence in 2D Semiconductor Light Emitting Device through Synchronous Injection of Electrons and Holes

AbstractAchieving efficient electroluminescence (EL) in 2D materials requires precise control over the injection and recombination of charge carriers—electrons and holes. In this study, a method is introduced to improve charge carrier injection in using transition metal dichalcogenides (TMDCs) based light emitting devices driven by alternating current (AC), achieved through dual pulse injection. The dual pulse device exhibits a notable enhancement in EL intensity, displaying a substantial increase as compared to the single pulse device, achieving an approximate sixfold improvement. The proposed dual pulse operated device configuration enables the independent control of electron and hole injection, facilitating the fine‐tuning of carrier recombination processes to improve the EL emission efficiency. Phase delay dependent EL characteristics are observed featuring a maximum integrated EL at a phase delay of 180° indicating an enhanced EL emission during out‐of‐phase pulse operation between the electrodes. Moreover, the dual pulse device exhibited a ≈3.5‐fold improvement in the device EL external efficiency (ηe) when compared to the device operated with a single pulse. Manipulating carrier recombination in TMDCs‐based LEDs opens up new opportunities to enhance their performance, enabling practical applications in display technology, lighting, optical communication, and electrically tunable light sources.

Strategic design of carrier transport layer-free homojunction perovskite photodetector

Abstract Perovskite photodetectors (PPDs) have attracted extensive attention due to their unique material properties. However, the use of electron and hole transport layers ( ETLs and HTLs) significantly increases the complexity of design and processing and reduces the reliability of the devices. To address these issues effectively, a simple strategy of eliminating the ETLs and HTLs by employing a perovskite homojunction is proposed. In this study, we examine a numerical design of p-n homojunction-based PPD without the use of carrier transport layers (CTLs), using the Silvaco TCAD simulator. To unlock the potential of the proposed design, the effects of doping concentration, mobility, thickness, and bandgap of p-perovskite and n-perovskite on the PPD photoelectric characteristics are investigated and optimized. The simulation results illustrate that a high-performance CTL-free PPD can be achieved by forming a p-n homojunction using a thin (&lt;200 nm) highly-doped (5 × 1017 cm−3) p-perovskite layer and a thick (&gt;600 nm) lowly-doped (5 × 1014 cm−3) n-perovskite layer with suitable mobility (1 ∼ 10 cm2 V−1 s−1). Under optimized conditions, our findings reveal an optimum detectivity of 7.4 × 1013 Jones at 750 nm, the optimum responsivity is found to be 0.42 A W−1 at 675 nm and the optimum EQE is 84% at 475 nm. These results highlight the promising potential of the p-n homojunction design as a device configuration for producing high-performance and reliable commercial PPDs without any CTL.

Enhanced performance of CaZrS3-based chalcogenide perovskite solar cells (CPSC): a theoretical study on optimization of hole transport material

Abstract The effective transformation of solar photons into electrical energy using innovative and environmentally friendly materials is a key focus in renewable energy research. In this study, chalcogenide perovskite CaZrS3 is employed as the absorber layer for solar photovoltaic applications, coupled with ZnO as ETL and Cu2O as HTL. A comprehensive theoretical investigation is conducted by utilizing the SCAPS-1D simulator to identify the most efficient photovoltaic device configuration. The performance of the solar device is evaluated by varying different parameters, including HTLs, thickness and defect density in the absorber layer, interface defect densities, CBO and VBO at ETL/PSK and PSK/ETL interfaces, series and shunt resistances, and the back contacts work function. The optimized solar device achieves a PCE of 21.25% with outstanding PV properties. This research highlights the potential of CaZrS3 as a chalcogenide absorber material for photovoltaic applications, demonstrating it as an effective and eco-friendly alternative.