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In this work, we implemented an off-axis digital holographic microscopy (DHM) setup to study the behavior of liquid drops on nanostructured porous silicon (PS) membranes. When a liquid comes into contact with the PS structure, capillary action and surface tension give rise to imbibition of the liquid into the intricate volume of the pores. At the same time, the vapor field developed around the drop enhances liquid condensation and evaporation into and from the pores. The complex interplay between these phenomena (capillary driven internal flows, condensation, and evaporation) is not yet fully understood but the methods we propose can provide new insights. We demonstrate how DHM allows determining the filling fraction of the porous membrane around drying drops of water and isobutyl alcohol. The phase information obtained from registered holograms provides quantitative information that permits to reconstruct the filling fraction along the porous membrane and its evolution during the drying process. Additionally, relevant parameters such as speed and contact angle during retraction of the drops can be measured. These methods can be further extended to other porous materials, such as porous alumina, micro- and macro-PS, to develop better fluid-dynamic models for describing fluid behavior in highly confined structures. [ABSTRACT FROM AUTHOR]

Three types of mesoporous silicon flakes were fabricated by anodization in methanoic hydrofluoric acid from the same substrates (heavily doped p-type). Even though anodization current density, rinsing, drying method, and storage condition were the same for all three wafers, the resulting porous silicon (PSi) structures had very different properties. They had very different colors. Two of them showed quite high luminescence quantum yields (QYs), confirmed by very long luminescence lifetimes. The highest QY exceeded 50% for a peak photoluminescence wavelength of ∼750 nm. To date, this QY is the highest obtained for PSi and very importantly for silicon with large mesopores, which is typically not highly efficient (as opposed to silicon with small mesopores and microporous silicon). Large mesopores (>15 nm diameter) facilitate impregnation of various substances into luminescent material, such as metals for plasmonics and drugs for theranostics. The differing luminescent properties were correlated to electrolyte temperature during anodization, and evolution of the electrolyte batch (lowering of active fluoride content and buildup of hexafluorosilicate) used to anodize several wafers, whose effects are often overlooked when mass-producing PSi. Supercritical drying and completion of the slow growth of native oxide passivation in the dark leading to different final partially oxidized PSi structures are also important factors for the high QYs obtained. The highest QY was obtained with the structure having the most isolated Si nanocrystals in an amorphous Si oxide tissue. [ABSTRACT FROM AUTHOR]

A porous silicon carbide (SiC) ceramic filter was prepared at 1000°C using waste red mud (RM), SiC, pore‐forming agent, and catalyst. The influence of sintering temperature, RM content, and pore former on the mechanical performance and the porosity of porous ceramics were investigated, and based on the result optimal processing parameters were selected. The air and water permeability tests were carried out at room temperature. The stability of the ceramic filter under thermal shock and chemical treatment was investigated and corroded samples were characterized. The ceramic was prepared using optimized processing parameters obtained with a flexural strength of 65.36 MPa at a porosity of 30.15 vol.% and demonstrated good performance in terms of pure water flux, oil, and turbidity removal efficiency from industrial wastewater. The filtration and permeation results indicated that the SiC filter prepared in this study is suitable for various applications, particularly in the remediation of oil‐polluted water. [ABSTRACT FROM AUTHOR]

The field-effect transistors (FETs) based on reduced graphene oxide (rGO) with SiO2, porous silicon (PS), and oxidized porous silicon (PSox) supporting layers were obtained. The influence of charged impurities in the silicon substrate and electrically active defects in the support layers on the electrical properties of the FETs was studied based on the capacitance-voltage characteristic analysis. Localized electron states in the SiO2, PS, and PSox supporting layers that affect the charge transfer in the rGO-based FETs were determined using thermally stimulated depolarization spectroscopy. The influence mechanisms of various supporting layers on the electrical characteristics of the obtained FETs are discussed. [ABSTRACT FROM AUTHOR]

In this study, the optical properties of porous silicon (PSi), such as the dielectric function, absorption coefficient, bandgap, reflectivity and refractive index, were studied as a function of porosities ranging from 3% to about 40% by using a supercell model in an ab-initio pseudo-potential plane wave (PP-PW) method based on density functional theory (DFT). To validate these theoretical results, various PSi samples were prepared by varying the etching parameters to achieve similar porosities. The PSi samples were subjected to UV–vis spectrophotometry in order to measure their reflectivity. The refractive indexes predicted by DFT were compared to those obtained by the Fresnel equation and the effective medium approximation methods (EMA), particularly Bruggeman's, Looyenga's and del Rio's model (dRZW). These studies showed that the PSi dielectric constant decreases with increasing porosity, which is consistent with a decrease in the refractive index. In addition, as the porosity of PSi rises, the bandgap energy values increase, which is closely related to the decrease in the refractive index. For low porosity, DFT and Looyenga refractive indexes fit better than dRZW or Bruggeman. Furthermore, when the porosity is increased, DFT gives similar results as dRZW and is better than the Bruggeman method. Moreover, at medium porosity (28 or 40%), DFT and EMA models agree well with the experimental refractive indexes of PSi. [ABSTRACT FROM AUTHOR]

In this study, a novel gamma-ray radiation sensor has been developed depending on a 1D photonic crystal (1D-PhC). Based on porous silicon (PSi) layer that has been penetrated by a conjugated copolymer (B-co-MP) which consists of BEHP-PPV and MEH-PPV, with a fractional ratio of 60:40. The suggested method for the development of the dosimeter is based on the shift of photonic band-gap to shorter wavelengths, where exposure to gamma-ray radiation at doses ranging from 0 to 20 kGy alters the refractive index of the (B-co-MP) copolymer. The fitted experimental data, the equation of Bruggeman effective medium, and the transfer matrix method (TMM) are the main axes in the framework of the current theoretical approach. The collected data shows that, within the visible range, the suggested sensor's sensitivity (224 nm/RIU) is high and stable over a 0-20 kGy applied-dose range. Also, we compared these results with previous research. [ABSTRACT FROM AUTHOR]

Helicobacter pylori (H. pylori) is a common pathogen with a high prevalence of infection in human populations. The diagnosis of H. pylori infection is critical for its treatment, eradication, and prognosis. Biosensors have been demonstrated to be powerful for the rapid onsite detection of pathogens, particularly for point-of-care test (POCT) scenarios. In this work, we propose a novel optical biosensor, based on nanomaterial porous silicon (PSi) and photonic surface state Tamm Plasmon Polariton (TPP), for the detection of cytotoxin-associated antigen A (CagA) of H. pylori bacterium. We fabricated the PSi TPP biosensor, analyzed its optical characteristics, and demonstrated through experiments, with the sensing of the CagA antigen, that the TPP biosensor has a sensitivity of 100 pm/(ng/mL), a limit of detection of 0.05 ng/mL, and specificity in terms of positive-to-negative ratio that is greater than six. From these performance factors, it can be concluded that the TPP biosensor can serve as an effective tool for the diagnosis of H. pylori infection, either in analytical labs or in POCT applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • A double carbon encapsulated porous composite with compact interface was designed. • The P-Si@rGO@C electrode exhibited inspiring rate-capability and long-cycling life. • The storage mechanism was explored via reaction kinetics, Ex-situ tests, and DFT. • A Li x Si prelithiation suspension was provided to enhance the ICE of the full cell. Developing high-performance composites with fast charging and superior cycle life is paramount for lithium-ion batteries (LIBs). Herein, we synthesized a double-shell carbon-coated porous structure composite with a compact surface (P-Si@rGO@C) using low-cost commercial micron-sized silicon (Si) instead of nanoscale silicon. Results reveal that the unique P-Si@rGO@C features high adaptability to volume expansion, accelerates electron/ion transmission rate, and forms a stable solid electrolyte interphase (SEI) film. This phenomenon arises from the synergistic effect of abundant internal voids and an external double-layer carbon shell with a dense surface. Specifically, the P-Si@rGO@C anode exhibits a high initial coulombic efficiency (ICE) (88.0 %), impressive rate-capability (612.1 mAh/g at 2C), and exceptional long-term cyclability (972.2 mAh/g over 500 cycles at 0.5C). Further kinetic studies elucidate the diffusion-capacitance hybrid energy storage mechanism and reveal an improved Li+ diffusion coefficient (from 3.47 × 10-11 to 2.85 × 10-9 cm2 s-1). Ex-situ characterization confirms the crystal phase change of micron-sized Si and the formation of a stable LiF-rich SEI. Theoretical calculations support these findings by demonstrating an enhancement in the adsorption ability of Si to Li+ (from -0.89 to -0.97 eV) and a reduction in the energy migration barrier (from 0.35 to 0.18 eV). Additionally, practical Li x Si powder is shown to increase the ICE of full cells from 67.4 % to 87.9 %. Furthermore, a pouch cell utilizing the prelithiated P-Si@rGO@C anode paired with LiNi 1/3 Co 1/3 Mn 1/3 O 2 (NCM111) cathode delivers a high initial reversible capacity of 7.2 mAh and 76.8 % capacity retention after 100 cycles. This work provides insights into the application of commercial silicon-aluminum alloy powder in the anode of high-energy LIBs. [ABSTRACT FROM AUTHOR]

Solid‐state hydrogen storage using metal hydrides offers the potential for high energy storage capacities. However, the requirement for high‐temperature operations (above 400°C) and challenges with heat exchange are significant drawbacks. From this perspective, adsorption on porous materials presents a viable solution to these challenges. Carbon nanostructures, such as graphene and graphene oxide (GO) derivatives, are well‐suited for hydrogen storage because of their lightweight nature, low density, and large surface area. However, the primary obstacle for practical applications is the poor storage capacity of carbon nanostructures under ambient conditions. Utilizing a cost‐effective transition element such as nickel as a catalyst offers significant potential for storing hydrogen in atomic and molecular forms by invoking the spillover mechanism. Thermally reduced graphene oxide (TrGO) modifies the surface, providing abundant active sites that attract hydrogen effectively. Porous silicon (PS) enhances the surface properties of graphene sheets, attracting hydrogen to the surface. The current study assesses a synthesized TrGO, PS, and Ni composition to leverage their individual properties for hydrogen storage. Field‐emission scanning electron microscopy examines the sheet structure of TrGO (used as the host material) and the incorporation of PS and Ni on its surface. The calculated specific surface area of TrGO is ~450 m2 g−1. X‐ray diffraction is used to identify the various phases in the composition, while Raman spectroscopy measures the degree of disorder within the composition. The pressure‐composition isotherms reveal hydrogen storage capacities of ~6.53 wt% for the TrGO + PS composition and ~2.43 wt% for the TrGO + PS + Ni composition. Despite the decrease in weight percentage of TrGO + PS + Ni due to the higher Ni content, dissociation enhances the adsorption rate from 0.35 to 0.53 wt% h−1. [ABSTRACT FROM AUTHOR]

Porous silicon (PSi) has received a lot of attention in nanotechnology research in recent years for its potential use as sensing layers in sensor application. However, there have been relatively limited studies concerning the effect of varying contact gaps and bias voltages on the humidity sensor based on PSi. In this work, the nanostructure PSi layer was synthesized via the anodization method and fabricated at different annealing temperatures of 250 ℃, 450 ℃, 650 ℃, and 850 ℃. Subsequently, the four samples were deposited with varying gold (Au) contact gaps of 3.5 mm, 4.5 mm, 7.5 mm, and 8.5 mm. The morphological and structural characteristics of the PSi layer were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. The PSi-based humidity sensors with varied Au contact gaps were evaluated in a humidity chamber at 40–90% relative humidity (RH) levels with different bias voltages of 2 V, 5 V, and 10 V. The optimized fabricated PSi device was evaluated for its electrical behaviour using I-V measurement under various operating temperatures ranging from 25 °C to 100 °C. The findings showed that the enhanced PSi structure of the 450 °C annealed sensor produced the highest sensitivity performance of 18.4705 µA/%RH with stable output at a contact gap of 4.5 mm and a bias voltage of 10 V. The sensor exhibited a high surface area to volume ratio, which facilitated efficient interactions between surface active sites and water molecules, resulting in a highly sensitive humidity sensor. [ABSTRACT FROM AUTHOR]

This work presents the development and design of aptasensor employing porous silicon (PSi) Fabry‒Pérot thin films that are suitable for use as optical transducers for the detection of lactoferrin (LF), which is a protein biomarker secreted at elevated levels during gastrointestinal (GI) inflammatory disorders such as inflammatory bowel disease and chronic pancreatitis. To overcome the primary limitation associated with PSi biosensors—namely, their relatively poor sensitivity due to issues related to complex mass transfer phenomena and reaction kinetics—we employed two strategic approaches: First, we sought to optimize the porous nanostructure with respect to factors including layer thickness, pore diameter, and capture probe density. Second, we leveraged convection properties by integrating the resulting biosensor into a 3D-printed microfluidic system that also had one of two different micromixer architectures (i.e., staggered herringbone micromixers or microimpellers) embedded. We demonstrated that tailoring the PSi aptasensor significantly improved its performance, achieving a limit of detection (LOD) of 50 nM—which is >1 order of magnitude lower than that achieved using previously-developed biosensors of this type. Moreover, integration into microfluidic systems that incorporated passive and active micromixers further enhanced the aptasensor's sensitivity, achieving an additional reduction in the LOD by yet another order of magnitude. These advancements demonstrate the potential of combining PSi-based optical transducers with microfluidic technology to create sensitive label-free biosensing platforms for the detection of GI inflammatory biomarkers. [ABSTRACT FROM AUTHOR]

In this study, dual-face porous silicon layers (Df-PSi) and hybrid structures with (AuNPs/PSi/Si / PSi /AuNPs) configurations are fabricated and investigated. The Df-Psi layers were synthesized simultaneously using the dual beam laser supporting etching (DB-LSE) route, which employed two identical laser beams. The Df-PSi layers hybrid structures were produced by integrating Au-NPs into PSi in an HAuCl4 solution using a dipping technique. The results showed well-ordered, highly symmetrical Df-PSi and hybrid structures with minute variations in overall characteristics due to a small change in the absorption laser intensity during the etching process. Following the Df-PSi synthesis, hotspot vacancies among nanoparticles in hybrid structures and the size distribution, and specific surface area (SSA) of gold nanoparticles (AuNPs) showed a well-ordered realization. [ABSTRACT FROM AUTHOR]

The hydrogen evolution reaction (HER) stands out as one of the most extensively studied electrocatalytic reactions in literature. Herein, niobium has been tested for the first time for the catalysis of the HER in the form of nanometer-thick-films. The deposition of 5, 10, and 50 nm-thick Nb thin films onto both smooth and porous silicon substrates, the latter ones with mesopores with mean diameters of 13 nm and 7 nm, respectively, has been successfully achieved using magnetron sputtering, a highly precise and controllable technique allowing a very efficient deposition of Nb films. After the sputtering deposition, the samples were examined by Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Analysis (EDAX) analyses which confirmed the purity and uniformity of the Nb coating on all samples. Electrochemical tests revealed top-notch performance, with almost negligible onset potentials (es. 80 mV vs. RHE) and low Tafel slopes (es. 30 mV/dec), thereby paving the way for the future development of cutting-edge devices. • Niobium tested for the first time towards HER in the form of nanometer-thick-films. • Deposition of 5, 10, and 50 nm-thick Nb films on smooth and porous Si substrates. • Highly precise efficient and controllable deposition through magnetron sputtering. • Negligible overpotentials and low Tafel slopes. • Paving the way for H 2 production in a single, integrated Si-based device. [ABSTRACT FROM AUTHOR]

The synthesis of photodetectors for ZnO nanostructure films on various substrates, including p-type (100) silicon (Si), and porous silicon (pSi), has been achieved through the utilization of a straightforward technique known as the successive ionic layer adsorption and reaction (SILAR) method. To analyze the optical properties, surface morphology, and crystal structure of the ZnO layers, UV-Vis spectrometers, field emission scanning electron microscopes (FESEM), and X-ray diffraction (XRD) were employed. The characterization of the ZnO samples revealed that the number of SILAR cycles has a significant impact on the morphology and optical band gap of the synthesized layer. The Fourier-transform infrared (FTIR) spectrum successfully detected the distinctive extended vibration mode of ZnO. By conducting 20 cycles, high-quality hexagonal ZnO was obtained. The responsivity of the planar ZnO on silicon (ZnO/Si) and ZnO on the porous silicon (ZnO/pSi) surface exhibited variations depending on the substrate surface and bias voltage. The results indicated that the (ZnO/pSi) heterojunction demonstrated a high response in the visible range (350–850 nm) at a low bias voltage. On the other hand, the (ZnO/Si) photodetector displayed a high sensitivity of 666.66% at a low voltage of 1V in comparison to the (ZnO/pSi) photodetector, which exhibited a sensitivity of 483%. [ABSTRACT FROM AUTHOR]

Due to their significant physical and chemical characteristics, metallic nanoparticles (NPs) have extensive applications. There has been a lot of interest in NPs generation utilizing green synthesis, and x-ray diffraction (XRD) confirmed that green synthesized CdO NPs had a single-phase cubic structure. The average crystallite measure of nanoparticles was 38 nm. Nanoparticles with an unanticipated disk-like shape that agglomerated more in the scenario of green synthesis were observed in (SEM) photos. [ABSTRACT FROM AUTHOR]

Wound management remains a great challenge for clinicians due to the complex physiological process of wound healing. Porous silicon (PSi) with controlled pore morphology, abundant surface chemistry, unique photonic properties, good biocompatibility, easy biodegradation and potential bioactivity represent an exciting class of materials for various biomedical applications. In this review, we focus on the recent progress of PSi in the design of advanced sensing and delivery systems for wound management applications. Firstly, we comprehensively introduce the common type, normal healing process, delaying factors and therapeutic drugs of wound healing. Subsequently, the typical fabrication, functionalization and key characteristics of PSi have been summarized because they provide the basis for further use as biosensing and delivery materials in wound management. Depending on these properties, the rise of PSi materials is evidenced by the examples in literature in recent years, which has emphasized the robust potential of PSi for wound monitoring, treatment and theranostics. Finally, challenges and opportunities for the future development of PSi-based sensors and delivery systems for wound management applications are proposed and summarized. We hope that this review will help readers to better understand current achievements and future prospects on PSi-based sensing and delivery systems for advanced wound management. Porous silicon-based sensing and delivery systems show great potential in wound management applications including monitoring, treatment and theranostics. [Display omitted] [ABSTRACT FROM AUTHOR]

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The effective removal of complex pollutants is extremely challenging for environmental and material science, especially pollutants including detergents and pesticides do not decompose or degrade in the aquatic environment which cannot be easily removed. Here, a novel biocompatible superparamagnetic nanocomposite integrating the advantages of porous silicon nanoparticles is developed, the chelation ability of chitosan, and graphene‐oxide‐iron that can simultaneously adsorb complex hydrophobic and hydrophilic pollutants on their internal and external surfaces which have significantly improved pollutant removal efficiency over the current existing methods. A porous silicon nanoparticle (PSi) conjugated magnetite‐chitosan‐reduced graphene oxide (MCRGO) nanoparticles (PSi‐MCRGO) are synthesized for complete removal of detergent, pesticide, and toxic heavy metals cadmium and lead ions from water at a favorable room temperature. The adsorption behavior of the nanocomposites fits well with the Freundlich isotherm and pseudo‐second‐order kinetics model by adsorption mechanism. Moreover, the fresh and recycled nanocomposites are easily separated by an external magnetic field for reusability due to super magnetite response and show high binding capacity for toxic heavy metal ions. Furthermore, the nanocomposites are biocompatible and reusable, and for the fourth time, recycled nanocomposites can completely remove toxic heavy metals. Overall, the novel nanocomposites completely remove complex pollutants which hold great potential for real water treatment. [ABSTRACT FROM AUTHOR]

The effect of hydrofluoric (HF) acid concentration on the optoelectronic properties of porous silicon (PS) was investigated. The laser-assisted etching (LAE) method was used to prepare the PS samples. Etching parameters such as an etching period of 12 min and a current density of 20 mA cm−2 were relied upon. The crystallite size of the PS was investigated by XRD as well to provide an estimate of the degree of crystallinity of the etched samples. The XRD pattern exhibits significant (111) peaks at 28.4°. The FESEM investigation shows the roughness and hillocks on the entire surface which can be considered as a point to form small skeleton clusters that play an important role in the strong visible photoluminescence (PL). We can infer from our PL study that the PL peaks regarding the PS samples are related to S-band luminescence, corresponding to the blue–red emission 580–620 nm. A slight PL band position shifts toward shorter wavelengths, which could be explained by reductions in luminescent nanocrystal sizes with a porosity increase. Raman peak shifts and becomes asymmetrically broadened as the dimensions of c-Si are shrunk, as the HF concentration is increased, the Raman sharp peaks become more asymmetrical, and their peak locations shift to lower wavenumber in comparison with our reference bulk data. The analysis is performed on the electrical features of I–V characteristics, barrier height, and PS responsivity. The photosensitivity investigations reveal that responsivity is higher for PS sample prepared at 22% HF concentration. The resultant's PS showed the best stability of the photocurrent, indicating that a high concentration can improve the stability of porous silicon optoelectrical characteristics. Under various HF concentrations, the quantum efficiency is assessed. The obtained results demonstrated rather unique results for the most efficient photodetector performance. [ABSTRACT FROM AUTHOR]

In this study, we used the pulsed laser ablation (PLA) method to make Au:MgO nanoparticles on porous silicon (PS) substrates. The optical characteristics, crystallinity and surface morphology of generated Au:MgO nanoparticles have been investigated with utilizing XRD, TEM, AFM, UV–Vis, PL and fabrication of gas sensors examined at various laser energies. Au:MgO nanoparticles have been manufactured by pulsed laser ablation method (Q-switched) fundamental 1064-nm Nd:YAG, at different laser energies 600, 800 and 1000 mJ and 100 shots, and then sedimentation on surface of PS (porous silicon) layer prepared by photoelectrochemical etching method. The properties of samples are analyzed by XRD (X-ray diffraction), AFM (atomic force microscope) and TEM (transmission electron microscope). The prepared samples were spherical nanoparticles with an average of roughness and diameter 13.4 and 36.76 nm. The production of approximately spherical core- shell of Au:MgO NPs is indicated by TEM with a mean particle size of 10–55 nm. Also the face cubic-centered shape of Au:MgO NPs is revealed by XRD. Eventually, the diversity of running temperature on the sensor sensitivity, recovery times and the time of response for NO2 and H2S gas sensors fabricated from prepared specimens was studied. The maximal sensitivity of Au:MgO NPs/PS excised by laser energy of 800 mJ of NO2 gas was evaluated as 41.1%, while the maximal sensitivity of Au:MgO NPs/PS excised with a pulsed laser of 1000 mJ of H2S gas is much greater compared to NO2 gas. [ABSTRACT FROM AUTHOR]

In the present work, we used a pulsed laser deposition technique to embed TiO2 nanostructure on porous silicon substrates using a pulsed laser deposition process. Nanocrystalline porous silicon was synthesized using the photo-assisted electrochemical method. The study analyzed the optoelectronic characteristics of double junctions of TiO2/PS/n-Si structures as well as the PS/n-Si structure. We investigated the properties of TiO2/PS/n-Si and PS/n-Si structures, focusing on their structural, optical, and electrical features under ambient conditions. The XRD measurement indicated the formation of the anatase and rutile tetragonal phases with the preferred orientation anatase (101) plane in the prepared sample. The mean sizes of The TiO2 nanostructures deposited onto porous silicon substrates range from 45.97 to 109.23 nm. The degree of pore filling depends upon the laser fluences employed, varying from moderate to close to complete packing. The optical properties of TiO2/PS/n-Si structures showed decreasing reflectance after depositing on porous silicon. The TiO2 nanostructure produced on porous silicon exhibits five different spectra in the UV and visible range, as displayed in the room-temperature photoluminescence analysis. The current density–voltage characteristics of formed samples in dark and photoilluminated conditions are examined at room temperature. The properties of the TiO2/PS/n-Si structure enhance those of the PS/n-Si device. The highest specific detectivity of the TiO2/PS/n-Si devices is 32.45 × 1010 Jones in the visible region, while the ultraviolet region is 30.04 × 1010 Jones. The TiO2/PS/n-Si photodetectors possess an optimal relative quantum efficiency of 80.1% in the near UV region, whereas, in the visible range, the values of relative quantum efficiency are 51.8% at 531 nm and 54.5% at 634 nm. The findings reveal that formed photodetectors exhibit UV and visible light sensitivity after depositing TiO2 layers on porous silicon. However, the photodetectors produced using TiO2 nanostructures placed on porous silicon demonstrate greater sensitivity than those made from as-synthesized porous silicon. [ABSTRACT FROM AUTHOR]

Porous silicon (PSi) is an intriguing material with unusual optical and electrical properties, and researching its temperature-dependent photoluminescence (PL) qualities might provide important insights into its behavior. In this respect, we conducted a thorough investigation of the evolution of the PL band as a function of the temperature in order to elucidate luminescence properties using temperature-dependent photoluminescence (PL) measurement. An electrochemical approach was used to create the porous structures. Two well-known PL emission peaks were identified at 663 nm and 818 nm; the broad emission peak at 663 nm was attributed to surface states in porous materials. Based on the intensity evolution with measurement temperature, the current work suggests two distinct nonradiative recombination processes. The influence of surface conditions can be attributed to the thermal extinguishing behavior in the low-temperature region between 10 and 60K. Nevertheless, it is possible to attribute nonradiative recombination activities to thermal escape throughout the upper-temperature range, specifically from 60 to 300 K. It is well acknowledged that gaining a comprehensive understanding of the faults is highly advantageous when considering the application of porous silicon layers in optoelectronic or other devices. [ABSTRACT FROM AUTHOR]

In this study, cadmium oxide (CdO) was prepared by pulsed laser ablation in liquid (PLAL). The morphological structure and optical properties of the prepared CdO were determined by various analytical techniques, including SEM, AFM and XRD. The SEM images obtained showed that the prepared film exhibited cluster-like cubic structures. The AFM images showed a homogeneous and very uniform surface. In addition, XRD analysis revealed that the prepared film had a grain size of about 20 nm. The optical properties of the fabricated film showed an increase in absorbance values with a simultaneous increase in wavelength. The maximum value was measured at 340 nm, and the measured optical energy gap was about 2.55 electron volts (eV). The solar cell was produced by depositing a CdO film on the porous silicon. The fabricated solar cell achieved an efficiency of 0.16%. Therefore, the CdO film from this work could be an important factor for the development of gas sensors and solar cells. In addition, other powerful analytical techniques were performed in this study, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and photoluminescence (PL) observations.

Abstract In this study, a novel gamma-ray radiation sensor has been developed depending on a 1D photonic crystal (1D-PhC). Based on porous silicon (PSi) layer that has been penetrated by a conjugated copolymer (B-co-MP) which consists of BEHP-PPV and MEH-PPV, with a fractional ratio of 60:40. The suggested method for the development of the dosimeter is based on the shift of photonic band-gap to shorter wavelengths, where exposure to gamma-ray radiation at doses ranging from 0 to 20 kGy alters the refractive index of the (B-co-MP) copolymer. The fitted experimental data, the equation of Bruggeman effective medium, and the transfer matrix method (TMM) are the main axes in the framework of the current theoretical approach. The collected data shows that, within the visible range, the suggested sensor's sensitivity (224 nm/RIU) is high and stable over a 0-20 kGy applied-dose range. Also, we compared these results with previous research.

The measurement of patients' dosages of radiation caused by medical diagnostics continues to be challenging. A Cantor sequence photonic crystal structure using porous silicon doped with a polymer of polyvinyl alcohol, carbol fuchsin and crystal violet (DPV) is proposed. The influence rules of geometrical and optical parameters such as the radiation doses, number of periods, porosity of porous layers, incident angle and thickness of layers are investigated using MATLAB based on the transfer matrix method. The transmittance of the Cantor sequence of a defective photonic crystal sensor under different conditions is investigated to select the optimum conditions. The proposed system recorded the accepted sensitivity of 0.265 nm/Gy, FoM of 6.5 Gy − 1 , Q of 12,701, RS of 6 × 1 0 − 3 and LoD of 8 × 1 0 − 3 for gamma radiation. The suggested detector has simple design, accurate monitoring efficiency and immense potential for gamma radiation sensing. [ABSTRACT FROM AUTHOR]

The Ag-PSi@SiC@C electrode features a substantially higher lithium-ion mobility of 2.4 × 10−9 cm2·s−1, which is significantly greater than the mobility of silicon at 5.1 × 10−12 cm2·s−1. With this anode, the half-cell exhibits excellent rate capability and cycling stability at a current density of 2.0 A/g, with a capacity of 1321.7 mAh/g that is maintained over 200 cycles, dropping only to 962.6 mAh/g. [Display omitted] Silicon-based material is regarded as one of the most promising anodes for next-generation high-performance lithium-ion batteries (LIBs) due to its high theoretical capacity and low cost. Harnessing silicon carbide's robustness, we designed a novel porous silicon with a sandwich structure of carbon/silicon carbide/Ag-modified porous silicon (Ag-PSi@SiC@C). Different from the conventional Si C interface characterized by a frail connection, a robust dual covalent bond configuration, dependent on Si C and Si O C, has been successfully established. Moreover, the innovative sandwich structure effectively reduces detrimental side reactions on the surface, eases volume expansion, and bolsters the structural integrity of the silicon anode. The incorporation of silver nanoparticles contributes to an improvement in overall electron transport capacity and enhances the kinetics of the overall reaction. Consequently, the Ag-PSi@SiC@C electrode, benefiting from the aforementioned advantages, demonstrates a notably elevated lithium-ion mobility (2.4 * 10−9 cm2·s−1), surpassing that of silicon (5.1 * 10−12 cm2·s−1). The half-cell featuring Ag-PSi@SiC@C as the anode demonstrated robust rate cycling stability at 2.0 A/g, maintaining a capacity of 1321.7 mAh/g, and after 200 cycles, it retained 962.6 mAh/g. Additionally, the full-cell, featuring an Ag-PSi@SiC@C anode and a LiFePO 4 (LFP) cathode, exhibits outstanding longevity. Hence, the proposed approach has the potential to unearth novel avenues for the extended exploration of high-performance silicon-carbon anodes for LIBs. [ABSTRACT FROM AUTHOR]

Escherichia coli (E. coli) bacteria identification is important in many areas, such as environmental monitoring and medical diagnostics. Conventional techniques frequently lack specificity and sensitivity. This study investigates the fabrication and characterization of a high-sensitive E. coli bacteria sensor using mesoporous silicon prepared by an electrochemical etching process under different low current densities. This study explores a high-sensitive E. coli sensor grown in nutrient agar at 36.5 °C, deposited on the mesoporous silicon surface, with morphology analyzed using scanning electron microscopy (SEM) and current–voltage characteristics measured. The XRD analysis confirmed the peaks of silicon material with a polycrystalline nature. FTIR demonstrated Si–H bonds which approve the porosity process. Results indicated that silicon etched at 3 mA/cm2 had small slit mesopores and large nanoparticles (73–102 nm) and at 9 mA/cm2, the smallest non-aggregated nanoparticles (54–83 nm) and largest pores (20 nm) were achieved. This study concludes that mesoporous silicon etched at 9 mA/cm2 provides the best performance for E. coli detection, demonstrating its potential for high-quality biosensor applications. [ABSTRACT FROM AUTHOR]

Modifying photo-anode structures in DSSC devices is still challenging in improving efficiency. This study focused on the ZnO rod growth on several porous silicon substrates using the hydrothermal method and determining which porous silicon is appropriate for DSSC applications. The materials used for the growth solution were Zn(NO3)26H2O 0.05 M and C6H12N4 0.25 M. The hydrothermal process was carried out at 90°C for 6 h and then annealed at 450°C for 30 min. SEM revealed that PSi pore influences the structure, diameter, and density of ZnO rods. ZnO structures formed in ZnO rods with a dominant vertical growth direction, ZnO rods with an intersection direction, and flower-like ZnO rods. The diameter of the PSi pore affected the density of ZnO rods grown on the PSi. The average diameter size and the density of ZnO rods vary from 747.66-1610.68 nm and 0.22-0.90 rod/μm2. XRD confirmed the presence of ZnO hexagonal wurtzite, Si cubic, and SiO2 monoclinic. UV-Vis spectrometry characterization results showed that sample reflectance was influenced by ZnO rod density and PSi pitch. The larger density of ZnO rods and the smaller pitch of the PSi pore will lead to lower reflectance. In addition, band gap values were obtained in the 3.06-3.75 eV range. FTIR identified the existence of a ZnO vibration bond, indicating that ZnO was successfully grown on all PSi substrates. The ZnO rods grown on P15S1180 are expected to have more appropriate properties among all five samples for DSSC photoanode.

The exceptional photoelectromagnetic characteristics of rare-earth elements contribute significantly to their indispensable position in the high-tech industry. The exponential expansion of the demand for high-purity rare earth and related compounds can be attributed to the swift advancement of contemporary technology. Nevertheless, rare-earth elements are finite and limited resources, and their excessive mining unavoidably results in resource depletion and environmental degradation. Hence, it is crucial to establish a highly effective approach for the extraction and reclamation of rare-earth elements. Adsorption is regarded as a promising technique for the recovery of rare-earth elements owing to its simplicity, environmentally friendly nature, and cost-effectiveness. The efficacy of adsorption is contingent upon the performance characteristics of the adsorbent material. Presently, there is a prevalent utilization of porous adsorbent materials with substantial specific surface areas and plentiful surface functional groups in the realm of selectively separating and recovering rare-earth elements. This paper presents a thorough examination of porous inorganic carbon materials, porous inorganic silicon materials, porous organic polymers, and metal–organic framework materials. The adsorption performance and processes for rare-earth elements are the focal points of discussion about these materials. Furthermore, this work investigates the potential applications of porous materials in the domain of the adsorption of rare-earth elements. [ABSTRACT FROM AUTHOR]

In this work, the capacity of porous silicon (PS) machined by laser photoetching was studied as an ethanol sensor, as well as the influences of the type and the conductivity of the crystalline silicon used to obtain sensors. The resistivities used were 1–10 and 0.0014–0.004 Ω∙cm, both wafers were n-type. The response of the device was determined at room temperature (27 °C). The results can be used to appropriately select the conductivity of semiconductor materials to be used as sensors. Infrared spectroscopy confirms the absorption of ethanol in the surface of the photoetched PS. Morphological analysis revealed a macroporous structure, with pore diameters of 2.6 and 0.39 μm for the wafers of 1–10 and 0.0014–0.004 Ω∙cm respectively. The macroporous structure demonstrates a high sensibility and exhibited excellent sensing characteristics during the detection of low concentrations of ethanol. The quantity of ethanol was registered with the changes in the voltage of operation. The performance of the sensor was characterized by curves of voltage vs. time. The minimum quantity of ethanol analyzed was 1 µl. The results demonstrate that photoetched PS has the potential to develop sensitive sensors. [ABSTRACT FROM AUTHOR]

Super hydrophobic porous silicon surface is prepared using a wet chemical synthesis route. Scanning electron microscopic investigation confirms a correlation between pore size and reaction time. SERS substrates are prepared by silver nanoparticle deposition on porous silicon surface. They exhibit excellent characteristics in terms of sensitivity, reproducibility, stability, and uniformity. They could detect rhodamine 6G in femtomolar range with SERS enhancement factor of ~ 6.1 × 1012, which is best ever reported for these substrates. Molecule-specific sensing of water pollutants such as methylene blue, glyphosate, and chlorpyrifos, is demonstrated for concentrations well below their permissible limits along with excellent enhancement factors. Porous silicon substrate functionalized with Ag nanoparticles demonstrates to be a promising candidate for low-cost, long-life, reliable sensors for environmental conservation applications. [ABSTRACT FROM AUTHOR]

Porous silicon structures are effective in trapping light due to the abundance of pores on their surface, finding widespread use in optical applications like photoelectric conversion, photon collection, and detection. We have successfully created micro-porous silicon with exceptionally high antireflection performance through electrochemical etching using different concentrations of silver catalysts. Results show that this germanium coated porous silicon structure has a smaller range of pore sizes, leading to a reduced reflectivity of 2.6 % under light radiation with wavelengths. To understand the antireflective mechanism further, we explored the surface reflectivity of porous silicon structures by coating the germanium metal on the porous structure. Importantly, germanium coated porous silicon structures with high surface quality and well-preserved pore integrity are identified as beneficial for achieving lower reflectivity in the incident light wavelength range of 300–1200 nm. These findings are significant for the design of porous silicon antireflective materials. [ABSTRACT FROM AUTHOR]

Modifying photo-anode structures in DSSC devices is still challenging in improving efficiency. This study focused on the ZnO rod growth on several porous silicon substrates using the hydrothermal method and determining which porous silicon is appropriate for DSSC applications. The materials used for the growth solution were Zn(NO3)26H2O 0.05 M and C6H12N4 0.25 M. The hydrothermal process was carried out at 90°C for 6 h and then annealed at 450°C for 30 min. SEM revealed that PSi pore influences the structure, diameter, and density of ZnO rods. ZnO structures formed in ZnO rods with a dominant vertical growth direction, ZnO rods with an intersection direction, and flower-like ZnO rods. The diameter of the PSi pore affected the density of ZnO rods grown on the PSi. The average diameter size and the density of ZnO rods vary from 747.66 -1610.68 nm and 0.22 -0.90 rod/μm². XRD confirmed the presence of ZnO hexagonal wurtzite, Si cubic, and SiO2 monoclinic. UV-Vis spectrometry characterization results showed that sample reflectance was influenced by ZnO rod density and PSi pitch. The larger density of ZnO rods and the smaller pitch of the PSi pore will lead to lower reflectance. In addition, band gap values were obtained in the 3.06 -3.75 eV range. FTIR identified the existence of a ZnO vibration bond, indicating that ZnO was successfully grown on all PSi substrates. The ZnO rods grown on P15 S1180 are expected to have more appropriate properties among all five samples for DSSC photoanode. [ABSTRACT FROM AUTHOR]

Silicon (Si) is a promising anode material for next-generation lithium-ion batteries (LIBs) with its high theoretical specific capacity (4200 mAh/g). However, Si anode has a huge volume change rate (> 300%) and high cost compared to graphite, which limits the commercial application of Si anode. Carbon coating can effectively tackle the volume change and poor conductivity during cycling of Si anode. In this work, aluminum–silicon alloy was firstly etched by hydrochloric acid. Followed by a mixture with pyrolysis of phenolic resin, the carbon layer outside the silicon particles was deposited during heat treatment process. The carbon-coated porous silicon-carbon (Si/C) anode material demonstrates excellent electrochemical performance and porous structure, which relieves mechanical stress and inhibits volume expansion. The results show that Si/C present well electrochemical performance at a sintering temperature of 800 ℃. Specially, the Si/C anode delivers a high specific capacity of 1394.4 mAh/g at the current density of 0.5 A/g with 46.1% retention. Nitrogen-doped silicon carbon composite material (Si/NC) was synthesized to further improve the performance of Si/C anodes. The characterizations confirm good crystallinity, uniform carbon coating on silicon surfaces, and even distribution of Si, C, and N elements. Simultaneously, a highly stable reversible capacity of 1218.3 mAh/g with 42.7% retention over 300 cycles at a current density of 0.5 A/g was obtained. This research can provide an alternative approach for high-energy and low-cost silicon-based anodes for LIBs. [ABSTRACT FROM AUTHOR]

The long-time stability of the enhanced porous silicon (PS) optoelectronic properties using samarium (Sm) pore-filling were investigated based on experimental results. Non treated natural and thermally oxidized PS samples were taken as reference. The morphology evolution of the samples was observed by using a scanning electron microscope (SEM). Fourier-Transform Infrared spectra (FTIR) of Sm treated PS (Sm-PS) show the appearance of new band localized at 470 cm−1 and attributed to Sm–O-Si which is persistent after 7 months of air exposure. Photoluminescence (PL) characterization demonstrated a stable threefold increase in the PL intensity of the Sm-PS. However, a blue shift from 1.829 eV to 1.835 eV and 1.890 eV for both natural aged and the thermal annealed PS samples accompanied with a dwindling in the intensity are observed and attributed to the decrease in the silicon crystallite size. The deconvolution of Raman spectrum of Sm-PS sample shows the existence of three bonds localized at 520, 518 and 506 cm−1 and attributed to the crystalline Si substrate, the formation of silicon nanocrystallites (SiNCs) and the compressive strained PS layer after the deposition of Sm layer, respectively. The electrical properties were analyzed based on the effective minority carrier lifetime (τeff) and surface recombination velocity (Seff). The Sm treated samples show the highest τeff about 52 µs and as a result the lowest Seff comparing to the freshly prepared PS which exhibits a τeff of about 13.2 µs due to the passivating capability of Sm layer. These results highlight the effectiveness of coating PS with Sm layer suitable for light emission and photovoltaic applications. [ABSTRACT FROM AUTHOR]

The document is a contents list for the journal CrystEngComm, which focuses on the design and understanding of solid-state and crystalline materials. It includes a list of papers featured in the issue, covering topics such as photocatalytic hydrogen generation, thermal performance of glass coatings, and Zn ion storage performance. The journal is published by The Royal Society of Chemistry, a leading chemistry community. The document also mentions approved training courses offered by the society. [Extracted from the article]

Recently, silicon has been considered one of the preferred materials for the anodes of next-generation high-energy-density Li-ion batteries due to its advantages of high specific capacity, low working voltage, and abundant reserves. However, the huge volume change and poor electrical conductivity of silicon anodes during the lithiation and de-lithiation process seriously affect their practical application. Herein, honeycomb porous silicon is synthesized by a modified Stöber method and magnesium thermal reduction, which avoids using toxic gases (such as silane) in the traditional preparation of commercial nano-silicon. Moreover, the honeycomb porous structure can effectively alleviate the volume expansion during the charge/discharge process and agglomeration behavior of nano-silicon. Therefore, thanks to its unique structural merits, the honeycomb porous silicon anode is endowed with a reversible specific capacity of 824.1 mA h g−1 after 100 cycles at 0.5 A g−1 and 679.2 mA h g−1 even at an ultrahigh current density of 1.0 A g−1 after an extended cycling period of 200 cycles, which is almost twice that of commercial nano-silicon. More importantly, this finding offers promising advancements in designing silicon anodes in energy storage. [ABSTRACT FROM AUTHOR]

Porous Si 3 N 4 ceramics with an interconnected pore structure were prepared by a paraffin emulsified suspension method. The effects of the volume ratio of paraffin to silicon and Y 2 O 3 addition on the structure and properties of porous Si 3 N 4 were studied. Uniform dispersed pores introduced by the emulsified paraffine droplets can be observed in the green samples. With the increase of the volume ratio of paraffin to silicon, the bulk density and the strength of the sample were decreased, and the apparent porosity and Darcy permeability were increased. The formation of α-Si 3 N 4 whiskers could be promoted by the addition of the Y 2 O 3 during the nitriding process, and numerous nano whiskers could be obtained in the pores left by the paraffine droplets with suitable addition of the Y 2 O 3. The porous Si 3 N 4 with interconnected whiskers prepared via the paraffin emulsion method exhibited potential application for hot gas particular matter filtration. [ABSTRACT FROM AUTHOR]

Hybrid nanoparticles (NPs) with complex morphology, structure, and chemical composition are considered key building blocks of next-generation optoelectronic devices, catalysts, and sensitizers/agents for diverse biomedical applications. Laser ablation in liquid (LAL) has emerged as a promising route to design and produce unique nanocomposite NPs, yet control over the product's size and structure is limited by tuning laser parameters or the content of the surrounding liquid. In this paper, based on the example of porous Si prepared by electrochemical etching, we demonstrate an alternative route to control the size of the resulting NPs through the modification of the target material's porosity. In particular, we showed a 3-fold size reduction of the LAL-synthesized Si NPs as compared to the product obtained by the ablation of the common monocrystalline Si wafer. The produced nanocrystalline Si NPs demonstrate a narrow monomodal size distribution with an average diameter of around 200 nm, which cover a practically relevant size range, allowing the excitation of Mie resonances at visible and near-IR wavelengths. Moreover, by adding a certain controlled amount of acid metal precursor HAuCl4, we fabricated core–satellites and nanocomposite Au–Si NPs via similar facile single-pot reactive laser synthesis. The incorporation of Au into the Si NPs was found to enhance the near-IR light-to-heat conversion performance of the nanohybrids, as confirmed by numerical modeling and single-particle micro-Raman thermometry at 785 nm wavelength matching the NIR-I biological transparency window. The obtained results pave the way toward the milligram-scale production of pure and hybrid Si-based Mie-resonant NPs for photonic, optoelectronic, sensing, and biomedical applications, while highlighting additional degree of freedom for control over the obtained product characteristics. [ABSTRACT FROM AUTHOR]

Si 3 N 4 ceramics pose a challenge when it comes to the preparation of light-curing pastes with high depth of cure, elevated solid content, and low viscosity. This challenge is primarily attributed to their inherent characteristics, including high absorbance, a high refractive index, and suboptimal sphericity. Consequently, the application of Si 3 N 4 ceramics in 3D printing remains a complex endeavor. To address the intricacies associated with 3D printing using Si 3 N 4 ceramics, our research focuses on the utilization of Tetramethylammonium Hydroxide (TMAH) for pH adjustment in Si 3 N 4 ceramics. This adjustment aims to enhance the stability, curing depth, and viscosity of the slurry. Subsequently, we employ this Si 3 N 4 light-curing slurry for 3D printing, followed by sintering the printed materials. The evaluation includes testing for porosity, density, and flexural strength of the samples. Notably, our efforts yield porous silicon nitride ceramics boasting an impressive density of 1.8299 g/cm3, porosity measuring 43.718%, and remarkable flexural strength amounting to 275 MPa. [ABSTRACT FROM AUTHOR]

Detection of nonstructural protein 1 (NS1) in saliva is a potential solution to noninvasive, early dengue detection. However, NS1 in saliva detected using enzyme-linked immunosorbent assay reports only 64.7% sensitivity and is undetectable using rapid test kits even in acute cases. Exploiting surface-enhanced Raman spectroscopy (SERS) and silicon (Si) as a low-cost, abundant material, a nano silver-coated porous silicon SERS substrate was developed for the novel detection of low-concentration NS1. The conventional wet lab electrochemical method was used to fabricate the PSi template, whereas the drop deposition method was used to deposit the AgNP on the PSi. Using rhodamine as the Raman marker, an enhancement factor of 53 was obtained, with a 0.01-mg/mL limit of detection (LOD), which is not spectacularly impressive. However, surprisingly, the SERS substrate surface functionalized with the dengue antibody resulted in the visibility of several peaks related to NS1 up to 0.001 mg/mL. Advanced lithography methods can further lower the LOD and enhance the performance of the PSi-based SERS substrate. Moreover, PSi-based SERS substrate fabrication allows for mass production and low costs. The study successfully developed the SERS substrate for its intended novel application: to detect low-concentration NS1. [ABSTRACT FROM AUTHOR]

This report introduced a novel technique for epitaxial bottom-up deposition of macroporous zinc oxide thin films on porous silicon (PSi) substrates. For achieving a higher surface-to-volume ratio and improving the photon trapping ability of the ZnO top layer, an optimized high-porosity PSi substrate was chosen as the template. Then, ZnO thin film was grown on the PSi substrate using the radio-frequency sputter-deposition method. The morphology of samples showed that the epitaxial layer followed the porous nature of the PSi substrate and generated a macroporous ZnO structure. The influence of post-sputtering thermal treatment at different temperatures on the structural and optical characteristics of synthesized macroporous ZnO nanostructures was studied. According to the planar surface morphologies, the average grain size of the sputtered ZnO layers heated at 300, 400, and 500 °C were 826, 1027, and 1195 nm, respectively. These results conform with the increased average crystallite size of ZnO nanostructures with higher annealing temperatures. The calculated crystallite size values were 4.14, 7.76, and 8.84 nm for the annealing temperatures of 300, 400, and 500 °C, respectively. The optical properties of the deposited thin film were improved due to the annealing process at higher temperatures. The highest light absorption coefficient was reported for the thin film annealed at 500 °C. Next, prepared macroporous n -ZnO/ p -PSi samples were used to fabricate heterojunction solar cells, and their electrical properties were studied at room temperature. The optoelectrical results showed improved performance of the fabricated devices with higher annealing temperatures. The results showed an enhanced efficiency of 15.08 % for the optimized device with an annealing temperature of 500 °C, which is assigned to its increased surface and enhanced exciton generation. Moreover, this device showed lower series resistance of 4.74 Ω and higher shunt resistance of 2.98 KΩ compared to other devices with lower annealing temperatures. [ABSTRACT FROM AUTHOR]

Copyright of Refractories / Naihuo Cailiao is the property of Naihuo Cailia (Refractories) Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Inorganic Chemicals Industry is the property of Editorial Office of Inorganic Chemicals Industry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Silicon represents one of the most attractive anode materials in lithium-ion batteries (LIBs) due to its highest theoretical specific capacity. Thus, there is a most urgent need to prepare Si-based nano materials in a very efficient way and develop some reasonable approaches for their modification in order to resolve the short-falls of Si anodes, which include both low conductivity and huge volume changes during intercalation of lithium ions. In this work, the kerf loss silicon (KL Si) from the photovoltaic industry has been used as an inexpensive Si source for the preparation of a porous silicon/silver/carbon composite (pSi/Ag@C) as an anode material. Porous silicon was embedded with Ag particles via the Ag-catalyzed chemical etching process, providing additional space to accommodate the large volume expansion of silicon. After carbon coating from polymerization of tannic acid on the surface of pSi/Ag, a high-speed conductive network over the surface of silicon was built and contributed to enhancing the electrochemical performance of the anode. The pSi/Ag@C electrode discharge capacity maintained at a stable value of 665.3 mAh g−1 after 100 cycles under 0.5 A g−1 and exhibited good rate performance. Therefore, this study recommends that the method is very promising for producing a silicon anode material for LIBs from KL Si. [ABSTRACT FROM AUTHOR]

Copyright of Baghdad Science Journal is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The possibility of using a network of multi-walled carbon nanotubes (mwCNTs) as a low-cost humidity sensor is studied in the work. An increase in the electrical resistance and capacitance of the obtained sensors was revealed with increasing air humidity. The concentration dependencies of the sensing ability and the dynamic characteristics of resistive and capacitive mwCNT-based humidity sensors were investigated. It was established that the formation of the mwCNT network on the porous silicon (PS) substrate increases its sensitivity to water vapor. The response time of the humidity sensors based on the mwCVTs and the PS is less than one minute at room temperature. [ABSTRACT FROM AUTHOR]

In this study, the properties of the porous silicon (PS) photodetector were improved by depositing Au@In2O3 (core-shell) nanoparticles on the surface of PS. The Au@In2O3 NPs were prepared using the pulsed laser ablation in liquid (PLAL) technique at different laser energies of 500, 700, and 900 mJ, using a Nd:YAG laser with a wavelength of 1064 nm. The PS was prepared using the electrochemical etching (ECE) method, with an etching current density of 20 mA/cm2, an etching time of 15 min, and a hydrofluoric acid concentration of 25%. Structural, morphological, optical, and electrical measurements of the PS, Au@In2O3 NPs, and Au@In2O3 NPs/PS were conducted using the X-ray diffraction (XRD) test, field-emission scanning electron microscopy (FE-SEM) analysis, photoluminescence (PL), and UV-vis spectroscopy showed the highest peak of absorbance at 327–385 nm, and the photoluminescence (PL) peak of Au@In2O3 NPs was in the visible range show broad band and splitting for 399.5 nm for In2O3 NPs and 469 nm for Au NPs, while the PS peak was at about 561.8 nm. As a result, the photodetectors device system exhibited high responsivity (Rλ) and quantum efficiency in the visible area, the higher responsivity of the Au@In2O3 NPs/PS photodetector was measured as 0.1450 A/W for specimens prepared at a laser energy of 500 mJ/pulse. [ABSTRACT FROM AUTHOR]

Ag:Au nanoparticles are prepared and studied in the form of pure, stable, highly concentrated, and non-toxic core–shell; the method of preparation was the seed growth method which involves preparation of silver seeds and is done via a chemical reaction between AgNO3, Na3C6H5O7, and NaBH4 to produce them; the next step was done by another chemical reduction of C6H8O6 and HAuC14 in a CTAB solution in different quantities (0.4 ml, 0.6 ml, 0.8 ml, and 1 ml). The morphology study revealed that the Ag:Au (core–shell) NPs deposited on porous silicon (PS) exhibited strong adhesion, leading improved structural stability of the PS substrate. Analysis of the UV–Vis spectra of NPs showed a localized surface plasmon resonance (LSPR) band within the spectral range of (420 to 540) nm wavelength. As the amount of gold Au NPs increased, the LSPR band transitioned from two peaks to almost one. In this work, the Ag:Au (core–shell) NPs are manufactured by seed growth method these nanoparticles are deposited on porous silicon (PS). Photoluminescence spectra, X-ray, TEM, UV–vis, and Raman were found. This research will provide some guidance to the developers of the n-type based Ag:Au (core–shell) NPs/PS sensor. [ABSTRACT FROM AUTHOR]

This study investigates the impact of laser pulse energy (500 mJ/pulse) on silver, gold, and silver@gold NPs and deposited on porous silicon. The objective is to assess their effects on structural, optical, morphological, and electrical properties, aiming to identify optimal conditions. Nanoparticles are produced through the technique of pulsed laser ablation in liquid (PLAL). This involves employing a Q-switched Nd: YAG laser operating at a wavelength of 1064 nm and pulse duration of 10 ns. X-ray diffraction (XRD) analysis validates the crystalline development of (core–shell) NPs, evident from the presence of XRD peaks corresponding to Au and Ag NPs. Morphological analysis reveals excellent adhesion between NPs and the substrate (PS), enhancing structural stability. UV–vis spectra demonstrate a localized surface plasmon resonance (LSPR) band within the 420–540 nm range. This band shifts from two peaks to one with increased gold content. A comparison of the photoluminescence emission spectra of porous silicon and Ag@Au NPS/PS at room temperature. The porous silicon exhibits an extreme PL emission band broadening centered at a visible wavelength of 620 nm (2.033 eV), which reveals the excellent quality of the PS structure. Photodetector measurements highlight maximum responsivity for the Ag@Au/PS photodetector. These Ag@Au NPs show promising attributes for high-performance photodetector applications. [ABSTRACT FROM AUTHOR]