Structure Of Au Research Articles

Numerical optimization of cesium tin-germanium triiodide/antimony selenide perovskite solar cell with fullerene nanolayer

SCAPS-1D platform was used to simulate a solar cell with FTO/CdS/Sb2Se3/CuInSe2/Au structure which was recently fabricated by Liu et al. (2022) [1] [Journal of Energy Chemistry68 521–528 (2022)] and a very similar result was obtained. Reported parameters were Fill Factor (FF) = 53.60 %, short circuit current density (JSC) = 26.18 mA/cm2, open circuit voltage (VOC) = 0.37 V, and power conversion efficiency (PCE) = 5.19 %, while simulated parameters were FF of 54.68 %, JSC of 27.54 mA/cm2, VOC of 0.36 V, and PCE = 5.55 %. The advancements have been evaluated by analyzing FTO/CdS/Sb2Se3/CuInSe2/Au and FTO/C60/Sb2Se3/CuInSe2/Au configurations, serving as the reference cells. To improve the cell performance, the CdS layer was replaced with another layer (C60) which shows excellent electron transport properties. Replacing the CdS layer with C60 led to an increase in the power conversion efficiency by 65 % (from 5.55 % up to 9.20 %). In photovoltaic systems, the PCE constitutes a pivotal parameter that can be enhanced through the absorption of a broad spectrum of incident photons. Consequently, the implementation of two absorber layers within a solar cell, each characterized by a graded band gap energy, enables the capture of solar photons over a more extensive spectral range. Therefore, a perovskite containing a band gap of 1.5 eV, lead-free, and Sn-based was used as the second absorber layer in the device. Therefore, a solar cell with FTO/C60/CsSn0.5Ge0.5I3/Sb2Se3/CuInSe2/Au structure was simulated, and significant results were achieved. Results showed that inserting the CsSn0.5Ge0.5I3 layer led to an increase in PCE up to 11.42 %.

Modeling, Calculation and Realization of Au/Nb2O5 Substrates for Surface Plasmon Resonance Sensors

Introduction. Sensor devices based on the surface plasmon resonance (SRP) phenomenon are widely used among the tools of information and diagnostic technologies. The main part of a device based on the surface plasmon resonance phenomenon is a sensor substrate, which consists of a glass plate, a film of plasma-supporting metal, usually gold, and additional layers to increase the sensitivity of the research. Depending on the thickness of the additional dielectric layers, the following types of sensors can be implemented: a conventional SPR sensor with a gold film without a dielectric; an Au/dielectric SPR sensor with a dielectric thickness less than the critical one, in which the system can maintain the plasmonic mode; a waveguide sensor on a metal sublayer, with a dielectric thickness sufficient for the emergence of waveguide modes. The Au/Nb2O5 thin-film system is promising for creating sensor substrates due to the high refractive index of Nb2O5 and its exceptional chemical and mechanical resistance. The purpose of the work. This work is devoted to computer modelling, calculation of performance characteristics and implementation of Au/Nb2O5 sensor substrates for SPR devices, including the Plasmontest series devices developed at the Institute of Cybernetics of the National Academy of Sciences of Ukraine. The behaviour of the characteristics of the SPR substrates with a plasma-supporting gold film, SPR substrates with sensitivity enhancement by an additional layer of Nb2O5 of nanometre thickness and with a waveguide layer of Nb2O5 thickness more than 150 nm are analysed. Calculations were performed for both refractive sensors on SPR and biosensors. Results. The theoretical analysis was carried out by computer modelling in Winspall and calculations in MATLAB using the Fresnel equations and the matrix method, which allowed a comprehensive analysis of the shape of the reflection curves, angular sensitivity, resolution and angular ranges for sensors with different dielectric coatings. It is shown that at a thickness of 0-10 nm, the Au/Nb2O5 structure will work as a SPR sensor with increased sensitivity, and at a thickness of 150-210 nm as a waveguide sensor on a metal sublayer. But, as calculations have shown, only the Au/Nb2O5 SPR sensor is promising for practical implementation to increase the sensitivity of biosensor measurements. The work carried out on the development of thin-film technology, which includes vacuum deposition of a thin-film structure of adhesive Nb (1–2 nm), plasma-supported Au (50 nm), Nb (3–5 nm) and thermal annealing (to oxidise the top layer of niobium), made it possible to implement Au/Nb2O5 substrates for SPR studies. Experimental studies have shown that the angular sensitivity of the Au/Nb2O5 refractometric SPR sensor is 1.5 times higher than that of a SPR sensor with a single Au film at niobium oxide layer thickness of about 6 nm. Thus, the experimentally determined increase in the angular sensitivity of the Au-Nb2O5 SPR sensor is consistent with the theoretical data. Conclusions. Calculations have shown an increase in the angular sensitivity of SPR sensors for Au/Nb2O5 sensor substrates compared to conventional Au film substrates for both refractometric (1.6 times) and biosensor (1.8 times) studies. The sensors on Au/Nb2O5 substrates for SPR studies, which we have designed and practically implemented, are cheap to manufacture, have higher sensitivity, and due to the exceptional chemical and mechanical stability of Nb2O5, can be used repeatedly in rather aggressive environments. Keywords: computer modelling, surface plasmon resonance, sensor, refractometer, biosensor.

Numerical simulations of novel multi- chalcogenide CuAgBeSnSe4 based thin film solar cell with over 24% efficiency using SCAPS-1D

Abstract For solar cell applications, the multi-chalcogenide CuAgBeSnSe4 (CABTSe) shows promise as a potential absorbing material. In this study, numerical simulations were conducted for the ITO/CABTSe/Ag2S/Au structure, which was screened from a group of 50 CABTSe-based thin film solar cells (TFSCs) using the SCAPS-1D code. We explored the influence of various parameters such as thickness, doping concentration, defect density, mobility, and electron affinity on the photovoltaic performance of the screened device. Under optimized parameters, the open circuit voltage, short circuit current, filling factor, and efficiency of the photovoltaic device were 1.099 V, 25.5 mA/cm2, 86.48%, and 24.24%, respectively. This study provides an effective approach for using CABTSe-based TFSCs as a replacement for traditional Cu2ZnSn(S,Se)4-based TFSCs.

Electrocatalytic ammonia synthesis on bimetallic AuPd porous structures

In industry, production of ammonia mainly relies on the intensive Haber-Bosch process, but it consumes high energy with low efficiency and generates a large number of green-house gases. Electrocatalytic nitrogen reduction reaction (ENRR), as an alternative method for fixing N2 under ambient conditions, provides a feasible strategy for sustainable development of N2 cycle storage and utilization of renewable energy. However, traditional nanocatalysts exhibit extremely poor ENRR performance due to low activity of the solid structure and intense hydrogen evolution reactions of single component. Herein, we design and prepare porous gold–palladium nanoalloys (pAuPdNs), which effectively enhance ENRR by the excellent catalytic activity of Au and the significant N2 fixation ability of Pd, as well as the nanoporous structure and synergistic effect between alloy components. The electrochemical results show the NH3 yield of the catalyst is as high as 43.6 μg·h−1·cm−2, and Faradaic efficiency reaches 43.8%, which are superior to the performances of most reported water-based ENRR electrocatalysts. Besides, the selectivity of 95% and stability also exhibit enhancement than numerous reported researches. As compared with solid alloy and porous Au or Pd structures, the superiority of pAuPdNs states the influence of alloying and porous structure. Hence pAuPdNs are proved to be the efficient, stable, and promising electrocatalysts for N2 reduction reaction at ambient temperature and atmospheric pressure.

Solvent-Directed Bioactive Supramolecular Zinc(II)-Metallogels: Exploring Semiconducting Aptitudes of Fabricating p-n Junction and Schottky Devices.

α-Ketoglutaric acid-based supramolecular Zn(II) metallogels in N,N'-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) solvent (i.e., Zn-α-Glu-DMF and Zn-α-Glu-DMSO) were successfully achieved. Zinc(II) acetate salt and α-ketoglutaric acid directed a three-dimensional noncovalent supramolecular network individually entrapped with N,N'-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) solvent to accomplish their respective semisolid flexible metallogel frameworks. The gel features of these synthesized materials were verified by rheological experiments such as amplitude sweep and frequency sweep measurements. The discrete morphological arrangements were analyzed for these metallogel samples through field emission scanning electron microscopic (FESEM) analysis. Highly stacked interconnected blocks of Zn-α-Glu-DMF with hierarchical arrays are found due to the occurrence of diverse noncovalent supramolecular interactions present in the metallogel framework. A distinct spherical shaped microstructure with interconnected hierarchical assembly has been observed for the FESEM pattern of Zn-α-Glu-DMSO. FTIR spectroscopic measurement was carried out to detect some important stretching vibrations of xerogel samples of different metallogels as well as gel-constructing chemical ingredients. A substantial amount of peak shifting of xerogel samples for both metallogels is observed in FTIR analysis, indicating the presence of different noncovalent interactions. ESI-mass analysis portrays a possible metallogel-constructing strategy. The antibacterial potentialities of both metallogels were investigated. These materials exhibited good antimicrobial efficacy toward Gram-positive and Gram-negative bacterial strains (including Escherichia coli, Bacillus cereus, Staphylococcus aureus, Listeria monocytogenes, and Salmonella typhimurium). Both synthesized metallogels were successfully implemented to fabricate the photoresponsive semiconducting diode. These materials offer excellent photodiode parameters including an ideality factor and rectification ratio (ON/OFF ratio). Synthesized metallogels are used to successfully fabricate photodiodes with an Al/p-Si/metallogel/Au structure. The ideality factors (η) for Zn-α-Glu-DMF and Zn-α-Glu-DMSO are found as 1.3 and 2.3, respectively, in dark conditions. The rectification ratios for Zn-α-Glu-DMF and Zn-α-Glu-DMSO metallogels are also determined, and these are found as 40 and 10, respectively.

Synergistic ROS Generation via Core-Shell Nanostructures with Increased Lattice Microstrain Combined with Single-Atom Catalysis for Enhanced Tumor Suppression.

This study emphasizes the innovative application of FePt and Cu core-shell nanostructures with increased lattice microstrain, coupled with Au single-atom catalysis, in significantly enhancing •OH generation for catalytic tumor therapy. The combination of core-shell with increased lattice microstrain and single-atom structures introduces an unexpected boost in hydroxyl radical (•OH) production, representing a pivotal advancement in strategies for enhancing reactive oxygen species. The creation of a core-shell structure, FePt@Cu, showcases a synergistic effect in •OH generation that surpasses the combined effects of FePt and Cu individually. Incorporating atomic Au with FePt@Cu/Au further enhances •OH production. Both FePt@Cu and FePt@Cu/Au structures boost the O2 → H2O2 → •OH reaction pathway and catalyze Fenton-like reactions. This enhancement is underpinned by DFT theoretical calculations revealing a reduced O2 adsorption energy and energy barrier, facilitated by lattice mismatch and the unique catalytic activity of single-atom Au. Notably, the FePt@Cu/Au structure demonstrates remarkable efficacy in tumor suppression and exhibits biodegradable properties, allowing for rapid excretion from the body. This dual attribute underscores its potential as a highly effective and safe cancer therapeutic agent.

Modified Cu active sites by alloying for efficient electrocatalytic reduction CO2 to CO

Transition metals like Au, Ag, and Cu have been reported to be quite active for CO2 reduction. In this study, we use density functional theory (DFT) calculation to investigate the electronic structure and catalytic performance of Au, Ag, Cu and their alloys for CO2 reduction reaction (CO2RR). Theoretical calculations identified the combination of Ag, Cu, and Au in a face-centered cubic (fcc) alloy as an outstanding electrocatalyst for CO2 reduction to CO, with Cu as the active site. The d-orbital projected density of state (PDOS) profile suggests that alloying alters the electronic structure of the Cu site, thereby affecting the Gibbs free energy change for the formation of *COOH intermediate (ΔG*COOH). To demonstrate the theoretical prediction experimentally, we employ a top-down dealloying approach to synthesize a nano-porous structured AgCuAu alloy (NP-Ag5Cu5Au5). Electrochemical experiments validate that the ternary alloy catalyst is clearly better than unary and binary catalysts, showing a Faradaic efficiency (FE) for CO over 90% across a broad potential range of 0.6 V, with a peak of approximately 96% at −0.573 V vs. RHE. This study underscores the potential of multi-component alloys in CO2RR and establishes a theoretical basis for designing efficient catalysts for CO2 utilization.

Defect-engineering-based titanium dioxide nanowires for artificial optoelectronic synapses

Artificial optoelectronic synapses, as a typical neuromorphic device, have garnered significant attention due to their concurrent capabilities in processing visual perception and memory. In this study, we propose an artificial optoelectronic synapse with a dual-terminal metal-semiconductor-metal (Au/TiO2/Cr/Au) structure. By modulating the concentration of oxygen vacancy defects in TiO2, the device exhibits a significant persistent photoconductivity (PPC) effect. The devices successfully simulated the synaptic behaviors, including paired-pulse facilitation (PPF), short-term plasticity (STP), long-term plasticity (LTP), and the learning-forgetting process. In addition, the device array has the capability to recognize optical signals and exhibits an obvious response gradient under different optical powers. This demonstrates its ability to adaptively detect optical signals and simulate human visual memory.

ZnO-based triboelectric nanogenerator and tribotronic transistor for tactile switch and displacement sensor applications

Tribotronics, the coupling of triboelectricity and semiconductors, is a novel field that has sparked much interest in the nanoelectronics and nanoenergy industries. This work presents the fabrication of a ZnO tribotronic transistor by combining a ZnO thin film transistor (ZnO-TFT) and a triboelectric nanogenerator (TENG) operating in vertical contact separation mode. A Si/SiO2/ZnO/Au structure was used to construct a bottom-gated ZnO-TFT. Radiofrequency (RF) magnetron sputtering was employed to deposit ZnO thin film, and the Au contact was achieved through thermal evaporation. A range of annealing temperatures was investigated, and ZnO TFT annealed at 500 °C exhibited a maximum electron mobility of 5.47 cm2/V s and a high on/off ratio of 105. We also investigated the photoresponse of this optimized ZnO-TFT using a UV LED. A vertical contact separation mode TENG was fabricated using ZnO (tribo-positive layer) and polyvinylidene difluoride (PVDF, tribo-negative layer) and combined with the ZnO TFT to fabricate a tribotronic transistor. The drain current of the tribotronic transistor dropped from 2.9 to 0.02 µA at a drain voltage of 5 V when the tribo layers were separated by 15 mm. Within the separation region of 2 mm, the device showed a 1.29 µA/mm change in drain current demonstrating its effectiveness in displacement sensing. Unlike conventional TFTs, the TENG's output could successfully control the tribotronic transistor's drain current and was innovative in such domains where conventional electrical components were constrained. Furthermore, this ZnO tribotronic device was used as an active smart tactile switch by simply touching or releasing the ZnO TENG with a finger.

Dual-responsive electrochemical immunosensor for CYFRA21-1 detection based on Au/Co Co-loaded 3D ordered macroporous carbon interconnected framework

Cytokeratin 19 fragment antigen 21–1 (CYFRA21–1) is a protein fragment released into the bloodstream during the death of lung epithelial cells, serving as a predictive biomarker in diagnosing non-small cell lung cancer (NSCLC) and need to be accurately detected. Herein, a dual-responsive label-free electrochemical immunosensor was developed based on a three-dimensional ordered interconnecting macroporous carbon skeleton material modified with gold-cobalt nanoparticles (Au/Co NPs-3D MCF) to detect cytokeratin-19 fragment (CYFRA21–1). The three-dimensional ordered interconnect macroporous structure, by providing a high specific surface area and an electrochemically active area, not only enhances the electron transport channel and reduces mass transfer resistance, but also offers a confined region that elevates the collision frequency with the active site. In addition to exhibiting excellent biocompatibility for antibody binding, gold-cobalt nanoparticles contribute significantly to the overall robustness of the immunosensor. By capitalizing on the 3D network structure and collective effect of Au and Co NPs, the Au/Co NPs-3D MCF immunosensors exhibit exceptional response signals in both chronocurrent testing and square-wave voltammetry, allowing for a wide linear response range of 0.0001–100 ng/mL and a low detection limit. Moreover, the constructed immunosensor is capable of detecting CYFRA21–1 in human serum and has the potential for further extension to detect multiple biomarkers. This work opens up new avenues for the construction of other highly selective 3D network immunosensors.

In-plane radiation pattern generated by large particles in dielectric substrates

In this work we present the study of in-plane radiation patterns generated by particles with dimensions larger than the excitation wavelength. We studied the in-plane radiation of Au structures focusing on two cases: particles and triangular crystals. We found that the radiation patterns were produced by the scattering of the excitation field at the bottom edges of the studied structures. In addition, we found the in-plane radiation decay exponentially due to the refractive index contrast between the substrate and superstate. Furthermore, we proved that in-plane radiation patterns originating from different structures can interact and generate interesting geometries. Finally, in addition to our experimental studies, we show numerically calculated simulations which agreed with our experimental results and thus confirmed our findings.

MEMS reconfigurable terahertz meta-absorber with polarization-dependent and sensing characteristics

This study presents and demonstrates a design of a micro-electro-mechanical system (MEMS) reconfigurable terahertz (THz) metamaterial absorber (TMA) that shows tunable free spectra range with a maximum value as 166 GHz in transverse magnetic mode and switchable resonance from 1.24 THz to 1.53 THz. The unit structure of TMA consists of two movable rectangular resonators aside and an x-shaped resonator at the center comprising two c-shaped resonators connected upside down. The material configuration of TMA is typical of the metal–insulator-metal sandwich configuration. That is a bottom Au layer preventing the penetration of the THz wave, a dielectric SiO2 layer to accommodate and absorb the incident wave, and a patterned Au structure array to select the resonant frequency. The electromagnetic response of TMA could be flexibly modulated when the structure is reconfigured by changing the gaps between x-shaped resonators and rectangular resonators based on the MEMS platform. Meanwhile, owing to the asymmetry of resonant structure, the electromagnetic response of TMA could be tuned from single-, dual-, triple- quad-resonances by varying the polarization state of incidence. Furthermore, the sensitivity of TMA is explored and demonstrated with remarkable linearity under a variation of the surrounding environment refractive index from 1.0 to 2.0. The feasibility of TMA is validated as the experimental absorption spectra are well meet the simulation results. The above results indicate the proposed TMA possesses great potential applications in multiple resonance switches, polarization switches, and highly efficient environmental sensors.

Soft-Template-Based Manufacturing of Gold Nanostructures for Energy and Sensing Applications.

Implantable and wearable bioelectronic systems can enable tailored therapies for the effective management of long-term diseases, thus minimising the risk of associated complications. In this context, glucose fuel cells hold great promise as in- or on-body energy harvesters for ultra-low-power bioelectronics and as self-powered glucose sensors. We report here the generation of gold nanostructures through a gold electrodeposition method in a soft template for the abiotic electrocatalysis of glucose in glucose fuel cells. Two different types of soft template were used: a lipid cubic phase-based soft template composed of Phytantriol and Brij®-56, and an emulsion-based soft template composed of hexane and sodium dodecyl sulphate (SDS). The resulting gold structures were first characterised by SAXS, SEM and TEM to elucidate their structure, and then their electrocatalytic activity towards glucose was compared in both a three-electrode set-up and in a fuel cell set-up. The Phytantriol/Brij®-56 template led to a nanofeather-like Au structure, while the hexane/SDS template led to a nanocoral-like Au structure. These templated electrodes exhibited similar electrochemical active surface areas (0.446 cm2 with a roughness factor (RF) of 14.2 for Phytantriol/Brij®-56 templated nanostructures and 0.421 cm2 with an RF of 13.4 for hexane/SDS templated nanostructures), and a sensitivity towards glucose of over 7 μA mM-1 cm-2. When tested as the anode of an abiotic glucose fuel cell (in a phosphate-buffered solution with a glucose concentration of 6 mM), a maximum power density of 7 μW cm-2 was reached; however the current density in the case of the fuel cell with the Phytantriol/Brij®-56 templated anode was approximately two times higher, reaching the value of 70 μA cm-2. Overall, this study demonstrates two simple, cost-effective and efficient strategies to manipulate the morphology of gold nanostructures, and thus their catalytic property, paving the way for the successful manufacturing of functional abiotic glucose fuel cells.

Achieving a high-performance electrochemical sensor for electrochemical detection of ammonia–nitrogen based on electrodepositing PtAu alloys and polypyrrole on Ni foam

The environment pollution problmes resulting from ammonia-nitrogen have been paid more attentions. Efficient and accurate detection of ammonia–nitrogen in aqueous enivronment including tap water, lake water and sea water is meaningful. In this work, a novel PtAu alloy sensor was designed and fabricated via coelectrodeposition method on Ni foam (NF). In addition, polypyrrole (PPy) was electrochemically grown on NF surface to avoid corrosion of NF during the electrodepositing process of PtAu alloy. Under the optimal condition, the prepared Pt5Au3-PPy-NF-1 showed the great electrocatalytic performance for ammonia oxidation reaction with the current density of 15.55 mA and great detection ability with the high sensitivity of 8.2 µA µM−1, low detection limit of 1.05 µM and three linear ranges from 4 to 50 µM, from 50 to 400 µM and from 400 to 1000 µM. The enhanced performances could be attriubted to: 1) Pt showed the electrochemial catalytic activity for ammonia oxidation reaction and Au showed the lower adsortion energy to N atom, as well as optimized electronic structure of Pt and Au.

A numerical approach to optimize the efficiency of a novel HTL-free Sr3Ti2S7 Ruddlesden-Popper perovskite solar cell

The exceptional environmental and structural stability of two-dimensional Ruddlesden-Popper perovskites has made them appealing candidates for high-performance perovskite solar cells. Besides, Ruddlesden-Popper perovskites can be synthesized using low-cost solution processing and have tunable bandgaps as compared to their conventional three-dimensional counterparts. Therefore, a Ruddlesden–Popper perovskite solar cell has been reported in this investigation and the SCAPS program has been used to theoretically study the device performance of the proposed lead-free, environmentally friendly perovskite solar cell. A novel Sr3Ti2S7 material has been utilized as the light absorber for the first time in such a theoretical study. Two different configurations, employing WS2 and C60 electron transport layers have been presented and device simulations have been performed to optimize the solar cell. The utilization of C60 as an electron transport material did not prove to be beneficial for the solar cell as it suffered from major recombination losses. It was also found that higher doping concentration of the electron transport materials could help these cells achieve improved fill factor. The diffusion length of the electrons and holes with respect to absorber defect density was also determined. Mott-Schottky analysis proved that the ITO/C60/Sr3Ti2S7/Au structure had a lower flatband potential compared to ITO/WS2/Sr3Ti2S7/Au. Additionally, from the impedance spectroscopy results, the recombination lifetime of the ITO/WS2/Sr3Ti2S7/Au configuration was found to be 46.7 μs compared to only 12.9 μs for the ITO/C60/Sr3Ti2S7/Au architecture. It was also established that if the thickness of the absorber and the bulk defect concentration were optimized the ITO/WS2/Sr3Ti2S7/Au and ITO/C60/Sr3Ti2S7/Au solar cells could achieve conversion efficiencies close to 11.0 % and 10.0 % respectively.

MSM Fiber Optic Surface Plasmon Resonance Glucose Sensor Based on SnO2 Nanofibers/Au Structure

Glucose is an indispensable nutrient for metabolism in living organisms and is widely used in food, industry, and medical fields. Glucose is often added as a sweetener in food and often used in industry as a reducing agent for various products. In medical treatment, glucose is added to many drugs as a nutritional additive, and it is also an indicator that diabetics need to pay attention to at all time. Therefore, the market has a great demand for low-cost, high-sensitivity, fast, and convenient glucose sensors, and the industry has always attached great importance to the work of creating new glucose sensor devices. Therefore, we proposed a SnO2 nanofibers/Au structure multimode-single-mode-multimode (MSM) fiber surface plasmon resonance (SPR) glucose sensor. SnO2 nanofibers were fixed to a single-mode fiber core that had been plated with the Au film by electrospinning. When the glucose concentration increased at 5 vol% intervals, the corresponding resonance wavelengths had different degrees of redshifts. Comparing the two structures, as the glucose concentration range increased from 0 vol% to 60 vol%, the sensitivity increased from 228.7 nm/vol% in the Au structure to 337.3 nm/vol% in the SnO2 nanofiber/Au structure. At the same time, the linear correlation between the resonant wavelength and the refractive index of the two structures was greater than 0.98. Moreover, the SnO2 nanofibers/Au structure significantly improved the practical application performance of SPR sensors.

Evaluation of Upscaling the Selective Electrophoretic Deposition of Reduced Graphene Oxide on Miniaturized Au Interdigital Electrodes from Chip-to Wafer-Level

Today’s novel materials challenge the research industry to enhance the performance and to reduce the power consumption of microchips as well as to develop new sensor principles. All this applies pressure on the investigation of new economical mass production technologies for the integration into standard process sequences or on top of state-of-the-art CMOS devices. Since the discovery of graphene in 2004, many different variations have been investigated, thus the number of publications of graphene-based content grew from a few in 2004 exponential to 1.2 million only in 2019, according to Google Scholar analysis. The deposition of graphene-based materials at wafer-level is still difficult to do economically on standard SEMI wafers up to 8” diameter. In this publication, the selective electrophoretic deposition (EPD) of reduced graphene oxide flakes (rGO) will be shown. This technique is a very promising deposition method for large scale fabrication. The EPD of rGO particles is the only known way to create 3D surface topologies for an enhanced sensing area of electrochemical sensor applications e.g. biosensors. The electrical and chemical properties of this novel material provides a broad range of applications for possible sensor solutions [1, 2]. Firstly, the deposition will be shown on chip scale to gain optimum parameters in suspension preparation and EPD deposition time/voltage for a uniform particle deposition over the sensor area. Shortcuts from particles between the transmission lines or co-deposition on reference electrodes have to be avoided. This leads to a high selectivity in rGO particle deposition on Au-structures. Afterwards designs and experiments have been made on array level and a proof of concept wafer-level deposition with a low volume suspension is demonstrated. In previous work, the adhesion of rGO on Au structures in electrochemical sensors with a liquid flow, showed a migration of the deposited particles with the friction of the liquid [3]. Therefore, standard separation of particle agglomeration or splitting of primary particles with ultra sonic sonotrodes are not sufficient to gain highly concentrated suspensions with homogenous target particle distributions (< 0,5µm ≤ 1µm ≥ 5µm). For this reason, a novel particle crushing preparation by ball milling is introduced and enhanced selectivity with an improved adhesion is demonstrated. A full process of the preparation of the colloidal suspension with the definition of target particle sizes with an optimum zeta potential will be provided and the cathodic electrophoretic deposition shown [4, 5]. For the evaluation of the deposition experiments, stereo microscopy is used to reveal the selectivity on the interdigital electrode (IDE) structures (sensor area) and scanning electron microscopy (SEM) analysis is used to characterize particle sizes and 3D topography, in terms of primary and secondary particles (agglomerates). For this study, IDE structures with 15 different geometry variations (3µm to 15µm lines and spaces) are used that were manufactured [6] to evaluate the rGO deposition on chip level. A novel multisensory array design with eight sensing areas are presented, combined with wafer-level deposition as a proof of concept on a 200mm wafer.

Coupling Au with BOx matrix induced by Closo-boron cluster for electrochemical synthesis of ammonia

Au is considered as one of the most promising catalysts for nitrogen reduction reaction (NRR), however maximizing the activity utilization rate of Au and understanding the synergistic effects between Au and carriers pose ongoing challenges. Herein, we systematically explore the synergistic catalytic effect of incorporating Au with boron clusters for accelerating NRR kinetics. An in-situ abinitio strategy is employed to construct B-doped Au nanoparticles (2–6 nm in diameter) loaded on BOx substrates (Au–BOx), in which B not only modulates the surface electronic structure of Au but also forms strong coupling interactions to stabilize the nanoparticles. The electrochemical results show that Au–BOx possesses excellent NRR activity (NH3 yield of 48.52 μg h−1 mgcat.−1, Faraday efficiency of 56.18%), and exhibits high stability and reproducibility throughout the electrocatalytic NRR process. Theoretical calculations reveal that the introduction of B induces the formation of both Au dangling bond and Au–B coupling bond, which considerably facilitates the hydrogenation of *N2–*NH3. The present work provides a new avenue for the preparation of metal-boron materials achieved by one-step reduction and doping process, utilizing boron clusters as reducing and stabilizing agents.

Laser-Induced Reactions of 4-Aminobenzenthiol Species Adsorbed on Ag, Au, and Cu Plasmonic Structures Followed by SERS Spectroscopy. The Role of Substrate and Excitation Energy - Surface-Complex Photochemistry and Plasmonic Catalysis.

This study focuses on investigating the laser-induced reactions of various surface complexes of 4-aminobenzenethiol on Ag, Au, and Cu surfaces. By utilizing different excitation wavelengths, the distinct behavior of the molecule species on the plasmonic substrates was observed. Density functional theory (DFT) calculations were employed to establish the significant role of chemical enhancement mechanisms in determining the observed behavior. The interaction between 4-aminobenzenethiol (4-ABT) molecules and plasmonic surfaces led to the formation of surface complexes with absorption bands red-shifted into the visible and near-infrared regions. Photochemical transformations were induced by excitation wavelengths from these regions, with the nature of the transformations varying based on the excitation wavelength and the plasmonic metal. Resonance with the electronic absorption transitions of these complexes amplifies surface-enhanced Raman scattering (SERS), enabling the detailed examination of ongoing processes. A kinetic study on the Ag surface revealed processes governed by both first- and second-order kinetics, attributed to the dimerization process and transformation processes of individual molecules interacting with photons or plasmons. The behavior of the molecules was found to be primarily determined by the position and variability of the band between 1170 and 1190 cm-1, with the former corresponding to molecules in the monomer state and the latter to dimerized molecules. Notably, laser-induced dimerization occurred most rapidly on the Cu surface, followed by Ag, and least on Au. These findings highlight the influence of plasmonic surfaces on molecular behavior and provide insights into the potential applications of laser-induced reactions for surface analysis and manipulation.

Study of a solar cell with a silicon-based photodiode structure

This article presents the results of a study of the capacitance- voltage characteristics of MSM photodiode structures with silicon-based potential barriers. The results of studies aimed at creating Au-nCdS-nSi- pCdTe-Au photodiode structures for the spectral range of 1.0-1.4 microns with an area of 29 mm2, which were obtained by vacuum evaporation in a quasi-closed volume of sputtering layers of cadmium sulfide and cadmium telluride, are presented. onto a silicon substrate with resistivity ρ = 607.47 Ohm∙cm. A distinctive feature of the resulting photodiode Au - nCdS-nSi - pCdTe - Au structures are two-way sensitive and have a low capacitance value of C = 23.3 pF at room temperature.