Contact Work Function Research Articles

SCAPS numerical modeling of CBTS/WO3 thin film solar cell

The quaternary compound Cu2BaSnS4 (CBTS) has emerged as a suitable and attractive light-harvesting material due to its promising optoelectronic features as well as nontoxic and low-cost constituent elements. Yet efficiency of CBTS-based solar cells did not reach the Shockley-Queisser limit. Here, what we believe to be a novel structure ITO/WO3/CBTS heterojunction solar cell is designed and modeled using a solar cell capacitance simulator in one-dimension (SCAPS-1D). In this work, a what we also believe to be a novel WO3 as a buffer layer is proposed for the first time for the efficiency enhancement of CBTS thin film solar cells. Numerical investigation of the performance of CBTS-based solar cells without and with cuprous oxide (Cu2O) back surface field (BSF) is explored. The impact of thickness, doping density, bulk, and interface defect density of an absorber, buffer and window layer, working temperature, shunt and series resistance, back contact work function, and back surface recombination velocity were analyzed and optimized without and with the BSF layer. In this work, the optimized solar cell achieved an efficiency of 18.8%, fill factor (FF) of 83.79%, short-circuit current density (JSC) of 15.99 mA/cm2, and open circuit voltage (VOC) of 1.4 V without Cu2O BSF layer at optimal CBTS absorber and WO3 buffer layer thickness of 2 µm and 0.04 µm respectively. Furthermore, the efficiency boosted to 21.12% with VOC of 1.43 V, JSC of 16.8 mA/cm2 and FF of 87.77% by inserting 0.1 µm Cu2O BSF layer. Therefore, these results will facilitate the fabrication of an efficient and low-cost CBTS-based solar cell with promising WO3 and Cu2O as buffer and BSF layer, respectively.

Comprehensive device simulation of perovskite solar cell with CuFeO2 as hole transport layer

Abstract Solid-state organic-inorganic halide perovskite solar cells have attracted increasing interest due to their potential as high-efficiency, low-cost photovoltaic devices. In this study, we comprehensively simulate CH₃NH₃PbI₃ perovskite-based solar cells with CuFeO₂ as the hole transport material (HTM) layer, and compare them to cells using Spiro-OMETAD and Cu₂O as HTM layers, utilizing SCAPS-1D software. The effects of absorber thickness, back contact work function, CuFeO₂ thickness, acceptor concentration, and defect density at the CH₃NH₃PbI₃/CuFeO₂ interface are analyzed. The results indicate that delafossite CuFeO₂ is a promising HTM that could significantly enhance the performance of perovskite-based solar cells. TiO₂/CH₃NH₃PbI₃/CuFeO₂ solar cells demonstrate comparable photovoltaic performance to those using traditional Spiro-OMETAD when the back contact electrode work function exceeds 4.9 eV, and superior performance compared to those with Cu₂O and Spiro-OMETAD at work functions below 4.8 eV. A high acceptor concentration exceeding 10¹⁶ cm⁻³ in CuFeO₂ is recommended to achieve optimal photovoltaic performance. These simulation results highlight the significant potential of employing CuFeO₂ as an HTM layer in CH₃NH₃PbI₃ perovskite-based solar cells as an alternative to the organic Spiro-OMETAD.

Role of La2CuO4 as Buffer Layer for a Significant Improvement of the Performance of TiO2/Cu2O Based All‐Oxide Solar Cell: A SCAPS‐1D Numerical Analysis

AbstractCurrently, low‐bandgap Mott‐insulating materials are the most promising buffer layers (BLs) for solar power conversion efficiency, unlike organic‐halide or lead‐containing perovskite materials. They can reduce interfacial recombination by field effect passivation of heterojunctions while maintaining cost‐effectiveness and high thermal and electrical stability. Moreover, it is expected to obtain a high quantum efficiency due to multiple carrier generation caused by impact ionization from a single incident photon. This study uses the SCAPS‐1D simulator to estimate and improve the efficiency of Cu2O‐based solar cells using Mott insulator La2CuO4 (LCO) as a BL in both ideal and non‐ideal conditions. The simulations examine how BL thickness, carrier concentration, and defect density affect device performance. Also, different metal contact work functions and working temperatures are examined to improve cell performance. Considering all optimisation parameters in ideal conditions, Au/Cu2O/TiO2/Nb: STO solar cell structure without a BL has a PCE of 11.27%, while Au/Cu2O/LCO/TiO2/Nb: STO has 28.11%. By incorporating non‐idealities, the simulated solar cell can simulate actual conditions. The impact of each non‐ideality is studied in detail. These findings suggest that Mott insulating buffer materials have great potential for creating high‐efficiency photovoltaic (PV) devices, presenting a new avenue for research.

Performance optimization of FASnI3 based perovskite solar cell through SCAPS-1D simulation

The article provides a detailed look at the fabrication of a high-performance structure for FASnI3-based perovskite solar cells (PSCs). The FTO/CeO2/FASnI3/CuI/Au structure is designed using the Solar Cell Capacitance Simulator in One Dimension (SCAPS-1D) to investigate the fabricated PSC's performance. This investigation's main objective is to improve PSCs performance by using non-traditional Hole transport layer (HTL) and Electron transport layer (ETL) materials, such as CeO2 and CuI, which have both been the subject of limited research. Moreover, the investigation seeks to determine the impact of several perovskite layer characteristics, including bandgap (Eg), electron affinity (χ), acceptor density (NA), thickness (t), and defect density (Nt). Additionally, this study also investigates the effect of various back contact work functions. Significant improvements in solar cell parameters, such as power conversion efficiency (PCE) from 22.06% to 24.87% and current density (Jsc) from 26.0274 to 30.675 mA/cm2, were observed by optimizing the device's parameters. In contrast, the fill factor (FF) and open circuit voltage (Voc) decreased their values from 86.13% to 87.10% and 0.9843 to 0.9308 V, respectively. These findings show that our designed solar cell structure performs better than those with conventionally used HTLs and ETLs. Consequently, this study highlights the potential benefits of lead-free PSCs and presents fresh opportunities for their development and use in various solar applications.

Performance optimization of eco-friendly CH3NH3SnI3 based perovskite solar cell employing CH3NH3SnBr3 as hole transport layer by SCAPS-1D device simulator

This study focuses on the theoretical aspects of third-generation perovskite solar cells (PSC), with the aim of replacing traditional silicon-based counterparts. With potential for higher efficiency and low manufacturing costs, perovskite cells offer unique crystallographic structures allowing adjustments to photoluminescence wavelength. This research addresses challenges in cost-effective solar spectrum utilization and optimization of parameters, device architecture, and materials for high-efficiency cells. In this study, we simulated a perovskite-based solar cell (CH3NH3SnI3) using solar cell capacitance simulator-one dimension simulator under AM 1.5G illumination. The chosen electron transport layer is TiO2, and hole transport layer is CH3NH3SnBr3. The simulation explores variations in layer thickness, defect concentration, interface defects, doping concentration and electron affinity. Additionally, we analyzed the impact of back metal contact work function and temperature variations. Results indicate optimal absorber layer thickness at 0.5µm. Reduced defect concentrations, increased doping concentration and a higher work function for the back contact, enhance efficiency of PSC. The initial parameters yielded a 19.79% efficiency based on base values before optimization, which increased to 26.66% after optimization. According to the latest NREL data, the highest reported efficiency for PSC is 26.1%. This research provides insights into perovskite-based solar cell design for enhanced efficiency.

Exploring eco-friendly novel charge transport materials for enhanced performance of tin based perovskite solar cell

This pioneering simulation study explores the potential of perovskite materials, particularly the non-toxic methyl ammonium tin iodide (MASnI3), in solar cell technology. The investigation focuses on eco-friendly, solution-processed compounds—specifically, WO3 and In2S3 as Electron Transport Layers (ETL) and MoO3 and WSe2 as Hole Transport Layer (HTL)—to develop planar n-i-p MASnI3 perovskite solar cell (PSC) devices. WO3 is chosen for its solution processing and high electron mobility, while In2S3 offers n-type properties, superior carrier mobility, non-toxicity, and thermal durability. MoO3 and WSe2 are selected as HTLs for their efficient charge transport capabilities. Utilizing the solar cell capacitance simulator (SCAPS-1D) software, the study systematically evaluates alternative charge-selective materials, considering various parameters such as thickness (0.1 µm to 1.5 µm for absorber and 0.1 µm to 0.35 µm for CTLs), doping concentration (3.2E10 to 3.2E16 for absorber and E16 to E20 for CTLs), defect density, and energy band offset for MASnI3 PSCs. Four distinct n-i-p device structures are optimized, yielding impressive PCE improvements ranging from 14.63 % to 25.34 %, a significant 3 % enhancement compared to initial results. Notably, the WO3/MASnI3/WSe2 configuration exhibits limitations in electrical performance, while the other optimized structures demonstrate substantial efficiency gains. Further analysis investigates the impact of reflecting coatings (10 % to 90 %), varying contact work functions (5.2–5.8 eV), and temperature (300–400 K) on photovoltaic parameters. Critical factors including energy band offset, recombination current profile, and built-in potential, are meticulously examined, laying the groundwork for advanced PSC implementation. The study culminates in the In2S3/MASnI3/MoO3 device configuration, which achieves a peak efficiency of 25.34 %, showcasing superior thermal stability and an enhanced fill factor, thus propelling all-inorganic PSCs towards practical implementation.

Chalcogenide perovskites for solar energy applications: The role of Sn substitution in BaZrS3-based photovoltaic devices

This study investigates the photovoltaic potential of the chalcogenide perovskite BaZr1-xSnxS3, where x values of 0, 0.125, and 0.250 were chosen. The band gap of BaZrS3 (1.7 eV) is slightly larger than the optimal band gap for single-junction devices, and alloying with Sn has been explored to tune the band gap. The photovoltaic performance of devices with different absorber layers was simulated using the SCAPS-1D solar cell simulator software. The results show that the power conversion efficiency (PCE) increases with increasing Sn content, and the optimal PCE is achieved at x = 0.125. The effects of temperature, work function of the back contact, and band offset at the ETL/absorber and absorber/HTL interfaces on the device performance were also investigated. The results show that the PCE decreases with increasing temperature, and the optimal PCE is achieved at a back contact work function of 4.8 eV. The study shows that tailoring band offset at the ETL/absorber and absorber/HTL interfaces can lead to efficiencies about 20 %, highlighting BaZr1-xSnxS3 as a promising material for future high-efficiency solar photovoltaics.

Efficiency enhancement of novel ITO/ZnSe/CNTs thin film solar cell

This study presents a novel photovoltaic cell design utilizing a layered structure of Indium Tin Oxide (ITO), Zinc Selenide (ZnSe), and Carbon Nanotubes (CNTs) for enhanced solar energy conversion. We employed the Solar Cell Capacity Simulator (SCAPS-1D) to model and optimize the device under AM 1.5 spectrum conditions. Our simulations systematically investigated the influence of key parameters including layer thicknesses, doping concentrations, temperature, back contact work function, and parasitic resistances on cell performance. The optimized structure demonstrated a theoretical power conversion efficiency of 29.91%, with an open-circuit voltage (Voc) of 799 mV, a short-circuit current density (Jsc) of 43.49 mA/cm², and a fill factor (FF) of 86.02%. These promising results are attributed to the synergistic combination of CNTs' broad spectral absorption, ZnSe's effective charge separation, and optimized layer properties. We found that the CNT absorber layer's doping concentration significantly impacted cell performance, with an optimal value of 10¹⁷ cm⁻³. The ZnSe buffer layer thickness showed minimal effect on efficiency within the studied range. Temperature increases from 300 K to 400 K led to a significant efficiency drop from 33.97% to 24.65%, primarily due to Voc reduction. While these results represent idealized conditions and upper theoretical limits, they provide valuable insights for the potential of CNT-based solar cells. This study offers a roadmap for future experimental work in high-efficiency thin-film photovoltaics, highlighting the promise of novel material combinations and the importance of device architecture optimization.

TCAD-Based Design and Optimization of Flexible Organic/Si Tandem Solar Cells

In order to surmount the Shockley–Queisser efficiency barrier of single-junction solar devices, tandem solar cells (TSCs) have shown a potential solution. Organic and Si materials can be promising candidates for the front and rear cells in TSCs due to their non-toxicity, cost-effectiveness, and possible complementary bandgap properties. This study researches a flexible two-terminal (2-T) organic/Si TSC through TCAD simulation. In the proposed configuration, the organic solar cell (OSC), with a photoactive optical bandgap of 1.78 eV, serves as the front cell, while the rear cell comprises a Si cell based on a thin 70 μm wafer, with a bandgap energy of 1.12 eV. The individual standalone front and bottom cells, upon calibration, demonstrate power conversion efficiencies (PCEs) of 11.11% and 22.69%, respectively. When integrated into a 2-T organic/Si monolithic TSC, the resultant tandem cell achieves a PCE of 20.03%, indicating the need for optimization of the top organic cell to beat the efficiency of the bottom Si cell. To enhance the performance of the OSC, some design ideas are presented. Firstly, the OSC is designed by omitting the organic hole transport layer (HTL). Consequently, through engineering the front contact work function, the PCE is enhanced. Moreover, the influence of varying the absorber defect density of the top cell on TSC performance is investigated. Reduced defect density led to an overall efficiency improvement of the tandem cell to 23.27%. Additionally, the effects of the variation of the absorber thicknesses of the top and rear cells on TSC performance metrics are explored. With the matching condition design, the tandem efficiency is enhanced to 27.60%, with VOC = 1.81 V and JSC = 19.28 mA/cm2. The presented simulation results intimate that the OSC/Si tandem design can find applications in wearable electronics due to their flexibility, environmentally friendly design, and high efficiency.

The role of interface energetics in Sb2Se3 thin film solar cells

We comprehensively simulated the interface energetics at the Sb2Se3/CdS interfaces and showed its impact on device performance. The interface discontinuity, band bending at interface and energy level alignment generates interfaces issues and must be optimized for an optimal device performance. The design parameters for controlling interface. Metal contact work function preferably higher than electron affinity (EA) and Fermi level (EF) combined (EA + EF), should result in near Ohmic behaviour of contact. Secondly electron affinity of buffer could be tuned to achieve small positive conduction bandoffset (spike barrier) at absorber/buffer interface which lowers the chances of recombination through interface states. A pn + configuration with highly doped buffer layer, as compared to p-absorber, is favourable as it will extend depletion in absorber, providing additional drift to photo-generated carriers. Lastly, acceptor defect at Sb2Se3-CdS interface generate surface inversion and detrimental to performance. Donor defects occupying interface states are preferred condition for optimal device performance. We have compiled the optimal ranges for these controlling parameters, to achieve theoretically ideal values of energy level alignment and energetics, leading to optimal performance.

Enhancing CsSn0.5Ge0.5I3 Perovskite Solar Cell Performance via Cu2O Hole Transport Layer Integration

Perovskite solar cells (PSCs) have emerged as a promising alternative to traditional silicon solar cells due to their low cost of fabrication and high power conversion efficiency (PCE). The utilization of lead halide perovskites as absorber layers in perovskite solar cells has been impeded by two major issues: lead poisoning and stability concerns. These hindrances have greatly impeded the industrialization of this cutting-edge technology. In light of the harmful effects of lead in perovskite solar cells, researchers have shifted their attention to exploring lead-free metal halide perovskites. However, the present alternatives to lead-based perovskite exhibit poor performance, thus prompting further inquiry into this matter. The primary objective of this research is to investigate the use of Cu2O as a hole transport layer in combination with lead-free metal halide perovskite (CsSn0.5Ge0.5I3) to achieve superior performance. Through meticulous experimentation, the suggested model has achieved outstanding results by optimizing several key variables. These variables include the thickness of the absorber layer (CsSn0.5Ge0.5I3), defect density, and doping densities, as well as the back contact work function and the operating temperature associated with each layer. The proposed FTO/PC60BM/CsSn0.5Ge0.5I3/Cu2O/Au solar cell structure surpassed prior configurations by comprehensively examining key aspects such as absorber layer thickness and defect density, doping densities, and back contact work. The structure has been also compared with multiple electron transport elements and concluded that the proposed model functions superior due to the use of PC60BM as an electron transport layer and it has an improved electron extraction procedure. Finally, the proposed model has achieved the optimized values as Jsc of 31.56 mA/cm-2, Voc of 1.12 V, FF of 81.47%, and PCE of 27.72%. As a consequence of this research, the investigated structure may be an excellent contender for the eventual creation of lead-free solar power cells made from perovskite.

Boosting the efficiency up to 33 % for chalcogenide tin mono-sulfide-based heterojunction solar cell using SCAPS simulation technique

In the present article, an FTO/n-ZnO/SnS/Sb2S3/Au heterojunction photovoltaic cell structure was modeled and the cell performance in terms of output parameters viz. open circuit voltage (Voc), short-circuit current density (Jsc), efficiency (η) and fill factor (FF) by varying carrier concentration, and thickness of different layers involved, was studied at ambient conditions. The overall theoretical performance of the designed photovoltaic cell was examined using SCAPS 1-D simulation programme. The simulation programme operates by resolving semiconductor equations such as the Poisson equation, drift-diffusion equation, and continuity equation for both electrons and holes. The equations are generally solved in one-dimension (1D) in a steady state condition. The role of Sb2S3 HTL on the performance study of tin sulfide chalcogenide-based heterojunction photovoltaic cell (HPVC) was also analyzed. Moreover, the impact of functioning temperature between 273 K and 350 K on the performance of photovoltaic cell was observed, and an increase in temperature resulted in poor performance. The impact of different metal back contact work functions and some more electrical parameters viz. series-shunt resistances, defect concentration of layers and interfaces, and radiative recombination coefficients were also observed on HPVC. The simulation results revealed that the HTL Sb2S3 forms proper band alignment with the SnS chalcogenide absorber layer and enhanced the efficiency, η of HPVC by lessening the carrier recombination at the rear contact side. The dislocation and interface defect reduced significantly which leads to the smooth conduction of hole carriers, therefore, preventing of minority carriers to recombine within the absorber. A significant increase in the efficiency ∼33.24 % together with performance cell parameters Jsc ∼34.38 mA/cm2, Voc ∼1.09 V, and FF ∼88.49 % was observed.

Enhancing solar cell efficiency through tandem structures utilizing lead-free mixed cation perovskites and CZTSe absorber layers

A tandem structure efficiently boosts solar cell efficiency because it uses a larger spectrum of solar radiation and minimizes photon energy thermalization. High-performance tandem solar cells have historically been difficult to produce due to a shortage of high-performance, low-bandgap cells. The proposed design is based on the CH3NH3GeI3 (1.9 eV) as a wide band gap absorber layer and FAMASnGeI3 (1.4 eV) as a narrow band gap perovskite layer with CZTSe as HTL. This research investigates the effect of different ETLs, perovskite layer thicknesses and their doping concentration on the device's photovoltaic parameters. Furthermore, the effect of tunnel junction thickness and front contact work function on the solar cell performance has also been simulated. It has been noted that the PCBM presents a better efficiency device than the other ETLs. The Voc of different ETLs has been related to Vbi. Moreover, the optimized thicknesses of both perovskite absorber layers are 450 nm and 400 nm for MAGeI3 and FAMASnGeI3, respectively. The optimal doping density is found to be E14 cm−3. It has been observed that the tunnel junction's thickness and the front contact's work function also play an important role in optimized device efficiency. The tunnel junction thickness is 4 nm for lead-free mixed cation perovskite/CZTSe tandem solar cells. However, the work function of the front electrode of 4.4 eV is optimum for this structure. The proposed lead-free mixed cation perovskite/CZTSe tandem device shows significant performance parameters, i.e., Voc= 0.970 V, Jsc = 28.46 mAcm−2, FF = 84.43 % and PCE= 23.32 %

Correlation between defect properties and the performance of eco-friendly CsSnI3-based perovskite solar cells

This study investigates the potential use of eco-friendly, all-inorganic cesium tin iodide (CsSnI3) perovskite (PVK) as an absorber layer. Despite having higher temperature stability of CsSnI3, the challenge is to get a uniform and defect-free film that hinders the performance. To accomplish this goal, we investigated several performance-related variables for perovskite solar cells (PSCs), including material defect density (Nt ), transport materials, layer thickness, temperature impacts, and back contact work functions. Negative valence band or conduction band offset values indicate no barrier preventing photogenerated carriers from flowing into the charge transport layers. The simulation result shows that hole transport layer thickness shows a higher impact than electron transport layer thickness. For the PVK thickness of 500 nm and a carrier density of 1018 cm−3, the device offers an optimum power conversion efficiency of 20.1%. The performance is more significantly affected by the defects in the PVK material compared to the defects present at the interface. Higher recombination (Re−h+) occurs at the TiO2–CsSnI3 interface. Defects located within the deep-level trap positioned at the mid-point of the band gap energy (E g) have a negative impact on the performance. The temperature coefficient (C T) is approximately ‒0.367% K‒1, indicating excellent thermal stability in an open environment. The selection of ‘A’ cation, the addition of additives, or carefully controlled fabrication techniques can mitigate the defect. This research shows the strategy for creating defects-free PSC devices, ultimately enhancing performance and the stability.

Tailoring Contacts for High-Performance 1D Ta2Pt3S8 Field-Effect Transistors.

Materials with van der Waals (vdW) unit structures rely on weak interunit vdW forces, facilitating physical separation and advancing nanomaterial research with remarkable electrical properties. Recently, there has been growing interest in one-dimensional (1D) vdW materials, celebrated for their advantageous properties, characterized by reduced dimensionality and the absence of dangling bonds. In this context, we synthesize Ta2Pt3S8, a 1D vdW material, and assess its suitability for field-effect transistor (FET) applications. Spectroscopic analysis and electrical characterization confirmed that the band gap and work function of Ta2Pt3S8 are 1.18 and 4.77 eV, respectively. Leveraging various electrode materials, we fabricated n-type FETs based on Ta2Pt3S8 and identified Cr as the optimal electrode, exhibiting a high mobility of 57 cm2 V-1 s-1. In addition, we analyzed the electron transport mechanism in n-type FETs by investigating Schottky barrier height, Schottky barrier tunneling width, and contact resistance. Furthermore, we successfully fabricated p-type operating Ta2Pt3S8 FETs using a molybdenum trioxide (MoO3) layer as a high work function contact electrode. Finally, we achieved Ta2Pt3S8 nanowire rectifying diodes by creating a p-n junction with asymmetric contact electrodes of Cr and MoO3, demonstrating an ideality factor of 1.06. These findings highlight the electronic properties of Ta2Pt3S8, positioning it as a promising 1D vdW material for future nanoelectronics and functional vdW-based device applications.

Improved Performance of Lead‐Free Perovskite Solar Cells Based on Multi‐Absorber MASnI3/CsGeI3 Heterojunction by Device Simulation

AbstractLead‐free perovskite solar cell (PSC) is the direction of future development of PSCs due to its reduced toxicity. However, the power conversion efficiency (PCE) of the lead‐free PSCs is still lagging behind their lead‐based counterparts, which hinders their further application. Multi‐absorber approach can effectively overcome this problem as it allows the maximum utilization of solar spectrum. Therefore, in this study a novel lead‐free MASnI3/CsGeI3 heterojunction structure is proposed to boost the performance of PSCs based on single CsGeI3 absorption layer. The critical device parameters including absorber thickness, defect density, doping concentration, and back contact work function are studied and optimized using the numerical software SCAPS‐1D. Under optimized conditions, PSCs based on Sn/Ge bilayer structure yield a considerable PCE of 16.15%, significantly higher than the single CsGeI3 based PSCs (optimized PCE of 7.43%) with higher thermal stability. The simulation results indicate a huge potential of the proposed multi‐absorber heterojunction structure for highly efficient lead‐free PSCs, which will contribute to achieving clean and sustainable energy in the future.

Revealing bactericidal events on graphene oxide nano films deposited on metal implant surfaces.

At the time when pathogens are developing robust resistance to antibiotics, the demand for implant surfaces with microbe-killing capabilities has significantly risen. To achieve this goal, profound understanding of the underlying mechanisms is crucial. Our study demonstrates that graphene oxide (GO) nano films deposited on stainless steel (SS316L) exhibit superior antibacterial features. The physicochemical properties of GO itself play a pivotal role in influencing biological events and their diversity may account for the contradictory results reported elsewhere. However, essential properties of GO coatings, such as oxygen content and the resulting electrical conductivity, have been overlooked so far. We hypothesize that the surface potential and electrical resistance of the oxygen content in the GO-nano films may induce bacteria-killing events on conductive metallic substrates. In our study, the GO applied contains 52 wt% of oxygen, and thus exhibits insulating properties. When deposited as a nano film on an electrically conducting steel substrate, GO flakes generate a Schottky barrier at the interface. This barrier, consequently, impedes the transfer of electrons to the underlying conductive substrate. As a result, this creates reactive oxygen species (ROS), leading to bacterial death. We confirmed the presence of GO coatings and their hydrolytic stability by using X-ray photoelectron spectroscopy (XPS), μRaman spectroscopy, scanning electron microscopy (SEM), and Kelvin probe force microscopy (KPFM) measurements. The biological evaluation was performed on the MG63 osteoblast-like cell line and two selected bacteria species: S. aureus and P. aeruginosa, demonstrating both the cytocompatibility and antibacterial behavior of GO-coated SS316L substrates. We propose a two-step bactericidal mechanism: electron transfer from the bacteria membrane to the substrate, followed by ROS generation. This mechanism finds support in changes observed in contact angle, surface potential, and work function, identified as decisive factors. By addressing overlooked factors and effectively bridging the gap between understanding and practicality, we present a transformative approach for implant surfaces, combating microbial resistance, and offering new application possibilitie.

Design and numerical simulation of B‑γ CsSnI3‑based perovskite solar cells: Conventional versus inverted configurations

This paper introduces a thorough simulation study, based on SCAPS, into the realm of B-γ CsSnI3 perovskite solar cells (PSCs). The work encompasses an array of critical aspects ranging from material properties to device physics strategies and performance enhancement techniques. The core objective of this study revolves around the meticulous optimization of device performance, primarily through the enrichment and enhancement of the absorber layer. The intricate energy band alignment between photoactive layer and carrier transportation layers emerges as a key focus, prompting a systematic exploration of alternative materials. The study begins by validating the simulation models and parameters via performing a device modeling calibration versus an experimental p-i-n B-γ CsSnI3-based PSC with an efficiency of 10.10%. Next, both inverted (n-i-p) and conventional (p-i-n) cell configurations are considered, allowing for a comprehensive evaluation of their potential. The p-i-n configuration is optimized through investigating the band alignment between the hole transportation layer (HTL) and the absorber, achieving a power conversion efficiency (PCE) of 16.11%, and 14.55% in the ETL-free configuration after adjusting the rear contact metal work function. Similarly, it is shown that the n-i-p structure can achieve a PCE of 13.76% after optimizing the electron transportation layer (ETL), while upon optimizing the back contact work function led to a maximum PCE of 21.47% for the HTL-free structure. By delving into these multifaceted dimensions, this research contributes not only to the advancement of B-γ CsSnI3-based PSCs but also provides valuable insights into the most promising avenues for achieving elevated efficiency.

Investigation of sub-stoichiometric MoOx hole-selective contacts for rear junction passivating contact silicon solar cells

Carrier-selective contacts play a crucial role in improving the performance of silicon solar cells by reducing recombination losses. This study explores the use of sub-stoichiometric molybdenum oxide (MoOx) as a hole-selective contact material deposited via thermal evaporation. X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS) analysis reveal diverse Mo–O bonding configurations and a low work function of ∼5.02 eV for the MoOx film. The passivation properties of a cell-like structure with local MoOx contact are found to be comparable to those of a structure with a full front passivation layer, as evidenced by an implied open-circuit voltage (iVoc) of 703.2 mV. However, the conversion efficiency of the solar cell with MoOx contact is limited to 16.5 %, with reduced external quantum efficiency (EQE) at UV and visible wavelengths. The study proposes that optimizing the MoOx front contact's work function and passivation characteristics could improve the solar cell's efficiency to 21.8 %. This research demonstrates the potential of sub-stoichiometric MoOx as a promising hole-selective contact for silicon solar cells, highlighting the factors influencing its performance.

Design Simulation of Chalcogenide Absorber‐Based Heterojunction Solar Cell Yielding Manifold Enhancement in Efficiency

A large efficiency improvement, ≈4.5 times, in a solar cell based on earth‐abundant low‐cost SnS absorber with configuration glass/Mo/SnS/CdS/i‐ZnO/AZO/Al is reported in sharp contrast to prior experimental reports in the literature. Efficiency enhancement is attributed to tailored design at the absorber/buffer interface implemented via two‐step design modification vis‐à‐vis experimental benchmark. Design tailoring using simulation comprises substitution of sulfur composition in SnS by Se followed by replacing CdS buffer layer with wide bandgap, nontoxic Zn (O, S). The effect of sulfur composition variation by Se (i.e., SnS1−xSex) indicates an optimal Se mole fraction (x = 0.4) exhibiting maximum efficiency. In addition, optimization of the thickness, carrier density, and bulk defect density of the SnS1−xSex absorber result in an improved design. Replacing CdS buffer layer by ZnO1−ySy in SnS absorber‐based solar cell results in substantial improvement in device parameters; open circuit voltage (VOC) of ≈86% and current density (JSC) of ≈78% due to optimal band alignment at the SnS1−xSex/ZnO1−ySy heterojunction. It occurs when the sulfur mole fraction is 60% in the absorber layer and 70% in the buffer layer causing efficiency to rise to ≈17.87%. An optimal design comprising all the parameters including metal back contact work function, series and shunt resistance deliver an efficiency of ≈19.2%.