Nanotechnology

Metallic nanoparticles with different physical properties have been screen printed as authentication tags on different types of paper. Gold and silver nanoparticles show unique optical signatures, including sharp emission bandwidths and long lifetimes of the printed label, even under accelerated weathering conditions. Magnetic nanoparticles show distinct physical signals that depend on the size of the nanoparticle itself. They were also screen printed on different substrates and their magnetic signals read out using a magnetic pattern recognition sensor and a vibrating sample magnetometer. The novelty of our work lies in the demonstration that the combination of nanomaterials with optical and magnetic properties on the same printed support is possible, and the resulting combined signals can be used to obtain a user-configurable label, providing a high degree of security in anti-counterfeiting applications using simple commercially-available sensors.

Zero-dimensional quantum dots (QDs) and their hybrid structures having been rapidly developed are reshaping the design and performance of next generation ultrafast electronic and optoelectronic devices. The high-performance metrics achievable in photodetectors, solar cells, transistors, and other application areas can be realized through the use of QDs with their tunable electronic and optical properties. Recent advances in the synthesis of QD hybrid structures, where QDs are incorporated within other nanostructure dimensions (1D nanowires, 2D materials), have dramatically increased charge carrier mobility, lowered recombination rates, and resulted in highly controlled interfacial properties. Synergistic effects between these hybrid configurations are exploited, including improved charge separation and enhanced exciton dissociation, which are very important for having ultrafast response times and greater sensitivity. Advanced fabrication techniques such as chemical vapor deposition and solution based self-assembly, QD hybrids can be fabricated with highly controlled interfaces and optimal energy band alignments. Further, computational simulations such as density functional theory (DFT) and time dependent DFT have provided further insights into the charge dynamics and electronic interactions in these hybrid systems for guidance on their design and application. The potential of QD-based hybrid architectures in addressing future information processing demands is demonstrated in this work, setting the stage for the development of high-speed, low-power devices in communications, sensing, and renewable energy technologies.

Resistive random access memory (RRAM) is considered an attractive candidate for next generation memory devices due to its competitive scalability, low-power operation and high switching speed. The technology however, still faces several challenges that overall prohibit its industrial translation, such as low yields, large switching variability and ultimately hard breakdown due to long-term operation or high-voltage biasing. The latter issue is of particular interest, because it ultimately leads to device failure. In this work, we have investigated the physicochemical changes that occur within RRAM devices as a consequence of soft and hard breakdown by combining full-field transmission x-ray microscopy with soft x-ray spectroscopic analysis performed on lamella samples. The high lateral resolution of this technique (down to 25 nm) allows the investigation of localized nanometric areas underneath permanent damage of the metal top electrode. Results show that devices after hard breakdown present discontinuity in the active layer, Pt inclusions and the formation of crystalline phases such as rutile, which indicates that the temperature increased locally up to 1000 K.

Metasurfaces (MSs), two-dimensional arrays of engineered nanostructures, have revolutionized optics by enabling precise manipulation of electromagnetic waves at subwavelength scales. These platforms offer unparalleled control over amplitude, phase, and polarization, unlocking advanced applications in imaging, communication, and sensing. Among them, plasmonic MSs stand out for their ability to exploit surface plasmon resonances (SPRs)—collective electron oscillations at metal-dielectric interfaces. This phenomenon enables extreme light confinement and field enhancement, leading to highly efficient light-matter interactions. The remarkable sensitivity of SPR to refractive index variations makes plasmonic MSs ideal for detecting minute biochemical and environmental changes with exceptional precision. Additionally, their tunable SPR characteristics enhance multifunctionality, enabling adaptive and real-time sensing. By leveraging these advantages, plasmonic MSs address critical challenges in modern sensing, driving breakthroughs in biomedical diagnostics, environmental monitoring, and chemical detection. This perspective explores recent advancements in plasmonic MSs, emphasizing flexible, multifunctional designs and the transformative role of artificial intelligence in optimizing performance and enabling real-time data analysis.

This study presents a detailed investigation into the fluorescence properties of color centers in single-crystal diamond needles (SCDNs) synthesized via chemical vapor deposition. Using steady-state and time-resolved photoluminescence (PL) techniques, we identified color centers with zero-phonon lines at 389 nm, 468 nm, 575 nm (NV⁰), 637 nm (NV^–), and 738 nm (SiV^–). PL excitation spectroscopy conducted at room temperature revealed the complex electronic structure of some of these centers, paving the way for further investigation into their fluorescence properties. Lifetime measurements were performed for each center, with the 389 nm one exhibiting the longest decay time (∼30 ns), which is advantageous for enhancing quantum coherence, improving photon emission efficiency, and reducing power consumption. Altogether, these findings highlight the potential of SCDNs for quantum applications and confirm their promise as a platform for next-generation photonic and quantum devices.

Two-dimensional (2D) semiconductors have received a lot of attention as the channel material for the next generation of transistors and electronic devices. On the other hand, insulating 2D gate dielectrics, as possible materials for gate dielectrics in transistors, have received little attention. We performed an experimental study on bismuth oxychloride, which is theoretically proposed to have good dielectric properties. High-quality bismuth oxychloride single crystals have been synthesized, and their high single crystallinity and spatial homogeneity have been thoroughly evidenced by x-ray diffraction, Raman spectroscopy, x-ray photoelectron spectroscopy, transmission electron microscopy (TEM), and scanning TEM studies. We then mechanically exfoliated high-quality BiOCl crystals to fabricate metal–insulator–metal (MIM) capacitors and measured the dielectric properties at various frequencies and different thicknesses. We found that BiOCl exhibits an out-of-plane static dielectric constant up to 11.6, which is 3 times higher than 2D hexagonal boron nitride making it a suitable candidate for 2D dielectrics. We also carried out cross-section TEM studies to look into the MIM interface and provide some future directions for their integration with metal-dielectric interfaces and possibly with other 2D devices.

Graphene Oxide (GO) is a two-dimensional (2D) nanomaterial largely exploited in many fields. Its preparation, usually performed from graphite in an oxidant environment, generally affords 2D layers with a broad size distribution, with overoxidation easily occurring. Here, we investigate the formation, along the Hummers synthesis of GO, of carbon nanoparticles (CNPs) isolated from GO and characterized through morphological and spectroscopic techniques. The purification methodology here applied is based on dialysis and results highly advantageous, since it does not involve chemical processes, which may lead to modifications in the composition of GO layers. Using a cross-matched characterization approach among different techniques, such as x-ray photoelectron spectroscopy, cyclic voltammetry and fluorescence spectroscopy, we demonstrate that the isolated CNP are constituted by layers that are highly oxidized at the edges and are stacked due to π–π interaction among their aromatic basal planes and H–bonded via their oxidized groups. These results, while representing a step forward in the comprehension of the structure of long-debated carbon debris in GO, strongly point to the introduction of dialysis as an indispensable step toward the preparation of more controlled and homogeneous GO layers and to its use for the valorization of low molecular weight GO species as luminescent CNPs.

With advancements in thin-film deposition, nanofabrication, and material characterization techniques, quantum devices leveraging nanoscale quantum phenomena have emerged across various fields, including quantum computing, sensing, communication, and metrology. Among these, quantum sensing harnesses the unique properties of quantum systems to achieve highly sensitive and precise measurements of physical quantities such as magnetic and electric fields, temperature, pressure, and even biological events. In this perspective, we highlight some popular magnetic quantum sensors used for magnetic sensing and imaging, and emerging spintronic quantum sensors that exploit the quantum mechanical properties of electron spin for similar applications. Most of the techniques discussed remain in lab-based stages, with limited preliminary data reported. However, the authors believe that, with continued progress in spintronics, these nano- and micro-scale spintronic devices—offering superior and unique magnetic quantum properties—could open new horizons in biomedical applications, including single-cell and single-molecule detection, large-scale protein profiling, sub-micrometer resolution medical imaging, and beyond.

Nanochains (NCs) made up of a one-dimensional arrangement of magnetic nanoparticles (NPs) exhibit anisotropic properties with potential for various applications. Herein, using a novel self-assembly method we directly integrate single NCs onto desired substrates including devices. We present a nanoscopic analysis of magnetization reversal in 1D linear NP arrays by combining x-ray microscopy, magnetoresistance (MR), and micromagnetic simulations. Imaging the local magnetization along individual NCs by scanning transmission x-ray microscopy and x-ray magnetic circular dichroism under varying in situ magnetic fields shows that each structure undergoes distinct non-homogeneous magnetization reversal processes. The experimental observations are complemented by micromagnetic simulations, revealing that morphological inhomogeneities critically influence the reversal process where regions with parallel chains or larger multi-domain particles act as nucleation centers for the magnetization switching and smaller particles provide pinning sites for the domain propagation. Magnetotransport through single NCs reveals distinct MR behavior that is correlated with the unique magnetization reversal processes dictated by the morphology of the structures. This study provides new insights into the complex magnetization reversal mechanism inherent to one-dimensional particle assemblies and the effective parameters that govern the process.

To accurately achieve structure height differences in the range of single digit nanometres is of great importance for the fabrication of diffraction gratings for the extreme ultraviolet range (EUV). Here, structuring of silicon irradiated through a mask by a broad beam of helium ions with an energy of 30 keV was investigated as an alternative to conventional etching, which offers only limited controllability for shallow structures due to the higher rate of material removal. Utilising a broad ion beam allows for quick and cost effective fabrication. Ion fluence of the irradiations was varied in the range of 10¹⁶ ... 10¹⁷ ions · cm^-2. This enabled a fine tuning of structure height in the range of 1.00 ± 0.05 to 20 ± 1 nm, which is suitable for shallow gratings used in EUV applications. According to transmission electron microscopy investigations the observed structure shape is attributed to the formation of point defects and bubbles/cavities within the silicon. Diffraction capabilities of fabricated elements are experimentally shown at the SX700 beamline of BESSY II. Rigorous Maxwell solver simulation based on the finite-element method and rigorous coupled wave analysis are utilised to describe the experimental obtained diffraction pattern.

Conjugation and loading of piroxicam and its metal complexes; Palladium(II) (PdL₂) and Silver(I) (AgL) synthesized and characterized by different techniques including infrared, UV–Vis spectroscopy, spectrofluorimetry, transmission electron microscope, x-ray powder diffraction and Zeta potential analyses were achieved. Orange quantum dots (OQDs) nanoparticle showed good stability, encapsulation and loading efficiency and controlled release of loaded piroxicam and its metal complexes. Generally, new OQQs conjugates showed enhanced antimicrobial and anticancer activity. In vitro antimicrobial activity screening demonstrated that Ag(I)-OQDs conjugate displayed potent antibacterial effect that was 1.8-fold against E. coli higher than piroxicam (MIC = 31.85 µM), where Pd(II)-OQDs conjugate depicted the highest activity with MIC of 33.05 µM against P. aeruginosa. In case of G + ve bacteria, Ag conjugate had potent activity which was 2.3-fold on S. aureus higher than piroxicam (MIC = 43.12 µM), while Pd conjugate exerted promising activity that was 3.5-fold against E. faecalis higher than piroxicam (MIC = 74.57 µM). Ag conjugate showed the most promising antifungal activity with 2.5-folds more than piroxicam. The in vitro antiproliferative activity depicted that all synthesized conjugates showed better Cytotoxic effect than piroxicam, specifically Pd conjugate which had IC50 values with by 2-fold lower than piroxicam on human liver cancer cell line Hepg2. While Pd and Ag conjugates showed 2.3 and 1.9-fold higher effect on human colon cancer cell line HT-29 compared to piroxicam.

The present study focuses on the fabricate the SnS₂-ZnFe₂O₄ compound to be employed as electrode materials in pseudocapacitors and raise its capacitance via direct-current O₂ plasma (DCOP) treatment. To maximally increase the capacitance of the constructed electrodes, the best conditions concerning temperature, exposure time, and power, as features of DCOP, were initially determined. Using the three-electrode cyclic voltammetry measurements, the electrodes exhibited the highest specific capacitance (733 F g⁻¹) when the exposure time, output power, and temperature were set to 25 min, 1700 W, and 25 °C, respectively. The energy and power densities of the fabricated symmetric supercapacitor were estimated to be 43.5 Wh kg⁻¹, which is considered substantially high, and 750 W kg⁻¹, respectively, at a highest operating voltage of 1.5 V. The functional groups of the created electrodes were also analyzed, and it was found that the reason for considerable increases in the capacitance was improvement of the functional groups comprising oxygen such as O–Sn–O, Sn–O–C, and Fe–O on the surface of the SnS₂-ZnFe₂O₄ electrodes.

Ultrathin solar cell devices based on amorphous silicon offer significant advantages in terms of cost and stability, provided they are effectively integrated with light-trapping strategies. However, integrating these devices with photonic nanotextures is challenging due to the high defect concentrations that may result from the deposition of ultrathin material layers on textured substrates. This study utilizes a cost-effective, scalable approach using quasiperiodic nanowrinkles as textured substrates for ultrathin amorphous silicon solar cells fabricated in a p–i–n configuration, with a 100 nm absorber layer. To enhance the performance on the nanowrinkles, a dual p-layer architecture, comprising a thin hydrogenated amorphous silicon protective layer combined with a nanocrystalline p-type layer is employed. These nanowrinkle solar cell devices show significant improvements, up to ∼33%, in power conversion efficiency compared to their flat substrate counterparts. The dual p-layer approach is effective in mitigating the adverse effect of defects, demonstrating a maximum of ∼33% increase in short-circuit photocurrent densities compared to single-p-layer configuration in the highest efficiency device. Simulation studies are conducted to analyze the electrical characteristics and charge transport phenomenon of the device layers, and the improved performance of the final device.

Conventional treatment modalities for periodontitis are less effective in removing bacterial plaques and biofilms, which tend to induce an inflammatory microenvironment in periodontal tissue and lead to disease progression. To overcome this limitation, we designed a silver-anchored polydopamine (PDA) nanocomposites hydrogel system (P-Ag@PDA gels, ∼200 nm) for multisynergistic treatment of periodontitis. PDA nanoparticles could synergize with silver to exert powerful bactericidal activity and reduce tissue damage caused by reactive oxygen species (ROS) or inflammatory factors. Meanwhile, the low-temperature photothermal process facilitated the penetration of nanoparticles into the bacterial biofilm, solving the challenge of biofilm removal in periodontitis. Poloxamer 407 thermosensitive hydrogel helped the nanocomposites adhere to the bacterial surface, overcoming the problem of reduced efficacy due to the rapid loss of the drug in the oral cavity. The antibacterial, biofilm scavenging, ROS scavenging and anti-inflammatory properties of P-Ag@PDA gels were investigated in vitro and in vivo. The results revealed that P-Ag@PDA gels with NIR light stimulation were more effective than tinidazole (TNZ) in attenuating ROS-induced periodontal tissue damage and removing biofilms, while exhibiting similar antimicrobial effects. This study provided a highly promising biomaterial for the treatment of periodontal infections.

Nanosheets of mixed or cation-substituted Transition metal dichalcogenide (TMD) are promising materials for a range of applications, including electrodes for electrochemical energy storage devices. Yet such materials are expensive to produce in large quantities (gram levels or higher). Here, we report on a two-step process, which involves precursor pyrolysis and sulfur annealing for the preparation of bulk powders of Mo_xW_1−xS₂. The structural and morphological properties of the synthesized cation-substituted TMD alloy are compared with high-purity commercially sourced MoWS₂ and MoS₂/WS₂ hybrid specimens. Notably, the electrochemical characteristics of synthesized Mo_xW_1−xS₂ exhibit exceptional first-cycle specific charge capacities for lithium-ion (638 mAh g⁻¹), sodium-ion (423 mAh g⁻¹), and potassium-ion (328 mAh g⁻¹) half-cells. All the cells showed capacity decay in longer-term cycling tests, arising from volume changes in TMD conversion-type electrodes. To mitigate the capacity decay, a voltage cut-off method is implemented, which minimizes irreversibility and structural distortion of TMD during cycling, even at higher cycling currents with nearly 100% average cycling efficiency. The findings of this study demonstrate a proficient and scalable synthesis methodology poised to be utilized across an array of layered TMD materials, with benefits to both industry and fundamental research into alkali-metal-ion energy storage.

Surface-enhanced Raman scattering (SERS) has become a transformative analytical tool, attracting growing interest for its wide-ranging applications. The development of SERS-active materials is now a central research area, spurring innovation in various types of SERS substrates. While noble metal-based substrates remain extensively studied, semiconductor-based, non-metal substrates are garnering attention due to their unique advantages: excellent chemical stability, high carrier mobility, biocompatibility, and precise fabrication control. However, their generally weaker enhancement effects limit their utility, underscoring the need for strategies to boost their SERS activity. Understanding the complex enhancement mechanisms in semiconductor-based SERS substrates is critical for designing next-generation materials with metal-like enhancement factors (EFs). The interplay of charge transfer, localized surface plasmon resonance, and photonic effects makes the enhancement process inherently challenging to unravel. Therefore, the search for new materials with exciting optoelectronic properties, as well as more innovative solutions to increase their SERS sensitivity, continues to grow. In this review, we explore the latest advancements in semiconductor-based SERS substrates, dissecting the complex enhancement mechanisms and various modification strategies aimed at achieving metal-like high EFs. We present a comprehensive analysis of the methods used to improve the SERS performance of semiconductor substrates and conclude with potential future directions for advancing this dynamic field.

Localized surface plasmon resonance (LSPR) is an optical phenomenon associated with noble metal nanostructures. The resonances result in sharp spectral absorption peaks as well as enhanced local electromagnetic fields, which have been widely used in chemical and biological sensing. Over the past decade, as label-free analytical method, LSPR sensors have gained considerable interest and undergone rapid development. In addition to conventional refractive-index sensing through resonant wavelength shift, molecular sensing by colorimetry and imaging techniques have also been developed. Moreover, the LSPR sensors have been integrated with other techniques such as micro/nano fluidics and artificial intelligence (AI) to enhance their functionality and performances. In this work, we provide an overview of the recent advancement in LSPR sensors technology, including refractive-index, colorimetric, and imaging-based sensors, as well as the incorporation of new technologies like AI.

Due to the unique self-assembling structure and rheological properties, supramolecular gel lubricants have become the third major type of liquid lubricating materials to supplement the lubricating oils and greases. The molecular structures of gelators applicable to oil-based, water-based and extreme conditions base oils were summarized firstly. Furthermore, this review aims at exploring the relationships between the molecular structures of gelators and the gel-forming, rheological and tribological properties of gel lubricants. Based on the wide application of gel in various lubrication fields, the synergistic lubricating effect between gel lubricants and nanomaterials, films, textured surfaces were analyzed. The design of solid–liquid composite lubrication systems based on gel lubricants and solid lubricants were attempted to be highlighted and revealed. Finally, the perspectives on the development of gel lubricants and corresponding composite lubricating materials were presented.

The use of atomic layer deposition (ALD) and molecular layer deposition (MLD) in energy sectors such as catalysis, batteries, and membranes has emerged as a growing approach to fine-tune surface and interfacial properties at the nanoscale, thereby enhancing performance. However, compared to the microelectronics field where ALD is well established on conventional substrates such as silicon wafers, employing ALD and MLD in energy applications often requires depositing films on unconventional substrates such as nanoparticles, secondary particles, composite electrodes, membranes with a wide pore size distribution, and two-dimensional materials. This review examines the challenges and perspectives associated with implementing ALD and MLD on these unconventional substrates. We discuss how the complex surface chemistries and intricate morphologies of these substrates can lead to non-ideal growth behaviors, resulting in inconsistent film properties compared to those grown on standard wafers, even within the same deposition process. Additionally, the review outlines the strengths and limitations of several characterization techniques when employed for ALD or MLD films grown on unconventional substrates, and it highlights a few example studies in which these growth methods have been applied for energy applications with a focus on energy storage. With ALD and MLD continuing to gain attention, this review aims to deepen the understanding of how to achieve controllable, predictable, and scalable deposition with atomic-scale precision, ultimately advancing the development of more efficient and durable energy devices.

Zero-dimensional quantum dots (QDs) and their hybrid structures having been rapidly developed are reshaping the design and performance of next generation ultrafast electronic and optoelectronic devices. The high-performance metrics achievable in photodetectors, solar cells, transistors, and other application areas can be realized through the use of QDs with their tunable electronic and optical properties. Recent advances in the synthesis of QD hybrid structures, where QDs are incorporated within other nanostructure dimensions (1D nanowires, 2D materials), have dramatically increased charge carrier mobility, lowered recombination rates, and resulted in highly controlled interfacial properties. Synergistic effects between these hybrid configurations are exploited, including improved charge separation and enhanced exciton dissociation, which are very important for having ultrafast response times and greater sensitivity. Advanced fabrication techniques such as chemical vapor deposition and solution based self-assembly, QD hybrids can be fabricated with highly controlled interfaces and optimal energy band alignments. Further, computational simulations such as density functional theory (DFT) and time dependent DFT have provided further insights into the charge dynamics and electronic interactions in these hybrid systems for guidance on their design and application. The potential of QD-based hybrid architectures in addressing future information processing demands is demonstrated in this work, setting the stage for the development of high-speed, low-power devices in communications, sensing, and renewable energy technologies.

Inflammatory breast cancer (IBC) presents a formidable challenge due to its rapid progression and unique clinical characteristics within the various manifestations of breast cancer. Despite being rare, its aggressive nature demands innovative approaches beyond conventional treatments. Nanomedicine offers exciting possibilities for improving all types of breast cancer therapeutics including IBC. In this review, we critically assess the current treatment landscape for IBC, highlighting the limitations of traditional methods and addressing the pressing need for new therapeutic strategies. Although many nanomaterials have been explored for breast cancer therapeutics, either alone or in combination with other therapies, only a limited number of nanotherapeutics have been extensively studied for IBC treatment. This review further explores how advancements in nanotechnology, such as nanoparticle- mediated photothermal therapy, Photodynamic therapy, and nanomedicinal targeted therapies can offer novel avenues for addressing the unique biological, technological, and regulatory challenges posed by IBC. IBC-related various nanomedicines based combitorial therapies are highlighted in this review. It also provides a forward-looking perspective on key research directions and clinical applications.

Frictional losses between mechanical components have posed a longstanding challenge. The application of effective lubricants can markedly mitigate these losses. Recently, layered materials have garnered extensive research interest due to their superior lubricating properties. While studies on the lubrication mechanisms between interlayer atoms are increasingly common, the exploration of sliding mechanisms associated with intercalated foreign atoms in layered materials remains a subject of considerable uncertainty. In this work, we employed density functional theory (DFT) to investigate the sliding behavior of WS2 intercalated with different concentrations of heteroatom Sn atoms. The results indicate that the intercalation of Sn atoms effectively reduces the sliding barrier. As the concentration of intercalated Sn atoms increases, the enhanced electrostatic repulsion due to the increasing interlayer charge, combined with the gradual reduction in the total charge density fluctuation during the sliding process, leads to a decrease in the sliding energy barrier. Furthermore, with higher Sn atom concentrations, we observe a significant reduction in both friction force and shear strength.

As the basis of the modern electronics industry, electronic functional materials provide powerful support for the development of science and technology. BOPP dielectric films are widely used in capacitors for excellent dielectric advantages. In this paper, a topological-structured multilayer sandwich dielectric film was designed. BOPP was used as the outer layer, CPP/PVDF as the middle layer, and two-dimensional boron nitride nanosheets (BNNS) were added to the CPP/PVDF blend to enhance its breakdown strength. The sandwich-structured films had the highest discharged energy density of 5.17 J/cm3 at 3 vol% addition of BNNS in the middle layer, and the charge-discharge efficiency maintained at a high level of 82.1%. The dielectric and energy storage properties of BOPP sandwich films were effectively improved by the introduction of large aspect ratio fillers.

In this study, polyaniline-based conductive polymers doped with manganese oxide and cerium oxide were electrochemically synthesized for the first time. Unlike previous studies, manganese oxide and cerium oxide doped polyaniline synthesis was carried out in perchloric acid. The resulting composite materials were characterized using spectroscopic and microscopic techniques. The doped polyaniline composites were employed as electrode components in supercapacitors and analyzed using cyclic voltammetry and electrochemical impedance spectroscopy. Changes in capacitive behavior over cycling were examined via galvanostatic charge-discharge measurements. The areal capacitance of the cerium oxide and manganese oxide doped polyaniline electrodes, synthesized under optimal conditions, were measured as 950 mF/cm² and 660 mF/cm², respectively, at a charge-discharge current of 10 mA/cm².

Silicon (Si) (111)-(7×7) surfaces with wide terraces and bunched steps were passivated with atomic hydrogen (H) and subsequently etched by irradiation of atomic H. The atomic H can suppress the reactivity of Si surfaces by terminating the dangling bonds of Si surfaces. Meanwhile, atomic H can break the periodic atomic structures such as (7×7) on the Si surfaces. In the present study, we intermittently repeated the atomic H irradiation to the H-terminated Si(111) surface and frequency-modulation atomic force microscopy (FM-AFM) observation in a conventional vacuum chamber. When H2 gas was introduced to the cracker with a gas flow rate of 1 sccm (≈ 1.7×10–8 m3·s–1), corresponding to an atomic H flux of 2.5×1016 cm–2·s–1, one hour of the atomic H irradiation increased the roughness of the terrace from 1.4 nm up to 1.9 nm. With increasing the gas flow rate to 10 sccm, pits were formed on the surface and enlarged to 20–40 nm diameters across the bunched step with shallow flat bottoms and non-uniform winding edges. The surface etching probably starts from the adsorption of H on the lower-coordinated Si atoms exposed at the bunched steps. The side walls of pits seemed to consist of {110} and {100} facets that are readily etched due to the smaller number of the back bonds of Si atoms.

Nanosheets of mixed or cation-substituted Transition metal dichalcogenide (TMD) are promising materials for a range of applications, including electrodes for electrochemical energy storage devices. Yet such materials are expensive to produce in large quantities (gram levels or higher). Here, we report on a two-step process, which involves precursor pyrolysis and sulfur annealing for the preparation of bulk powders of Mo_xW_1−xS₂. The structural and morphological properties of the synthesized cation-substituted TMD alloy are compared with high-purity commercially sourced MoWS₂ and MoS₂/WS₂ hybrid specimens. Notably, the electrochemical characteristics of synthesized Mo_xW_1−xS₂ exhibit exceptional first-cycle specific charge capacities for lithium-ion (638 mAh g⁻¹), sodium-ion (423 mAh g⁻¹), and potassium-ion (328 mAh g⁻¹) half-cells. All the cells showed capacity decay in longer-term cycling tests, arising from volume changes in TMD conversion-type electrodes. To mitigate the capacity decay, a voltage cut-off method is implemented, which minimizes irreversibility and structural distortion of TMD during cycling, even at higher cycling currents with nearly 100% average cycling efficiency. The findings of this study demonstrate a proficient and scalable synthesis methodology poised to be utilized across an array of layered TMD materials, with benefits to both industry and fundamental research into alkali-metal-ion energy storage.

In this study, polyaniline-based conductive polymers doped with manganese oxide and cerium oxide were electrochemically synthesized for the first time. Unlike previous studies, manganese oxide and cerium oxide doped polyaniline synthesis was carried out in perchloric acid. The resulting composite materials were characterized using spectroscopic and microscopic techniques. The doped polyaniline composites were employed as electrode components in supercapacitors and analyzed using cyclic voltammetry and electrochemical impedance spectroscopy. Changes in capacitive behavior over cycling were examined via galvanostatic charge-discharge measurements. The areal capacitance of the cerium oxide and manganese oxide doped polyaniline electrodes, synthesized under optimal conditions, were measured as 950 mF/cm² and 660 mF/cm², respectively, at a charge-discharge current of 10 mA/cm².

Decoration of TiO₂ nanotube (TNT) arrays by AuPd nanoparticles (NPs) produces a dramatic enhancement in the rate of hydrogen generation through photocatalytic water-splitting under solar illumination. XRD and TEM confirmed alloy formation in bimetallic AuPd NPs while XPS ruled out a core-shell architecture in the AuPd NPs. Well-dispersed, size-controlled AuPd NPs were formed by sequential physical vapor deposition of Au and Pd on TNTs followed by spontaneous thermal dewetting (TNT-AuPd). TNT-AuPd samples were characterized by small tensile microstrains. For comparison purposes and to derive physical insights, an identical method was used to form TNT-Au and TNT-Pd samples wherein TNTs were decorated by monometallic Au and Pd NPs respectively. In every case, an accumulation-type heterointerface between TiO₂ and the metallic/bimetallic NPs was indicated by binding energy shifts in the Ti2p high-resolution x-ray photoelectron spectra (HR-XPS). Initial and final state effects in the Au4f HR-XPS pointed to a large number of Au atoms in low coordinate sites such as edges, kinks and corners as well as a slower excited atom relaxation in the alloy. A similar preponderance of Pd atoms at low coordinate sites was found along with the presence of a small amount of palladium oxide. The alloying of Au with a low Pd content on TNT yields significant enhancement in hydrogen production under UV–visible light in aqueous triethanolamine solutions. TNT-AuPd demonstrated the highest photocatalytic H₂ production rate of 2920 µmol g⁻¹ h⁻¹, which is 8.9 times higher than that of TNTs, 2.1 times that of TNT-Au, and 1.69 times that of TNT-Pd under solar illumination. We studied H₂ generation under UV-filtered solar illumination with TNT-AuPd outperforming monometallic Au- and Pd-NP decorated TNTs, which is attributed to the enhancement of the catalytic activity of Pd in an Au environment, the presence of Pd and Au atoms at low coordinate sites, and photoinduced electron transfer between TNTs and AuPd alloy NPs, where AuPd acts as an efficient electron sink, in turn reducing carrier recombination losses. AuPd bimetallic nanoparticles on TNTs, prepared via a simple anodization and vapor deposition method, exhibit excellent stability across multiple cycles and offer valuable insights for the development of efficient photocatalysts with promising potential for emerging energy applications.

Bottom–up synthesis of free-standing graphene using thermal plasma technology often results in flakes with smaller lateral dimensions (hundreds of nanometers) compared to top–down and substrate-based approaches (reaching centimeters in size) Dato (2019 J. Mater. Res.34 214–30). This limitation in size restricts the applicability of graphene in various applications. This study investigates a method to overcome this limitation by studying the reactor's quenching effect on the plasma plume exiting an radiofrequency inductively coupled thermal plasma thermal plasma torch. Local gas phase chemistry and graphene morphology were investigated during methane (CH₄) pyrolysis in argon plasma. Natural quenching suppression led to a production of few-layer (2–5 layers), near-micrometer-sized un-supported graphene sheets (∼2.8 µm perimeter) with less crumpling and a projected area of (2–5) × 10⁵ nm². Raman, transmission electron microscopy, thermogravimetric analysis, and x-ray photoelectron spectroscopy (XPS) analysis confirmed the high quality of the synthesized graphene. Sp² carbon composition in the sample was calculated using the D parameter obtained from the differentiated C KLL Auger peak in the XPS spectrum. A correlation between the gas phase chemistry and the graphene morphology demonstrated the significant effect of plasma reactor natural quenching and recirculation on the graphene synthesis and offers a potential for controlling the structure of unsupported graphene. The current study provides valuable insights that can pave the way for the development of reactors with a definite control over the morphology of synthesized graphene.

Spin–valley properties in two-dimensional (2D) semiconducting transition metal dichalcogenides (TMDCs) has attracted significant interest due to the possible applications in quantum computing. Spin–valley properties can be exploited in TMDC quantum dot (QD) with well-resolved energy levels. This requires smaller QDs, especially in material systems with heavy carrier effective mass e.g. TMDCs and silicon. Device architectures employed for TMDC QDs so far have difficulty achieving smaller QDs. Therefore, an alternative approach in the device architecture is needed. Here, we propose a multilayer device architecture to achieve a gate-defined QD in TMDC with a relatively large energy splitting on the QD. We provide a range of device dimensions and dielectric thicknesses and its correlation with the QD energy splitting. The device architecture is modeled realistically. Moreover, we show that all the device parameters used in modeling are experimentally achievable. These studies lay the foundation for future work toward spin–valley qubits in TMDCs. The successful implementation of these device architectures will drive the technological development of 2D materials-based quantum technologies.

Graphene Oxide (GO) is a two-dimensional (2D) nanomaterial largely exploited in many fields. Its preparation, usually performed from graphite in an oxidant environment, generally affords 2D layers with a broad size distribution, with overoxidation easily occurring. Here, we investigate the formation, along the Hummers synthesis of GO, of carbon nanoparticles (CNPs) isolated from GO and characterized through morphological and spectroscopic techniques. The purification methodology here applied is based on dialysis and results highly advantageous, since it does not involve chemical processes, which may lead to modifications in the composition of GO layers. Using a cross-matched characterization approach among different techniques, such as x-ray photoelectron spectroscopy, cyclic voltammetry and fluorescence spectroscopy, we demonstrate that the isolated CNP are constituted by layers that are highly oxidized at the edges and are stacked due to π–π interaction among their aromatic basal planes and H–bonded via their oxidized groups. These results, while representing a step forward in the comprehension of the structure of long-debated carbon debris in GO, strongly point to the introduction of dialysis as an indispensable step toward the preparation of more controlled and homogeneous GO layers and to its use for the valorization of low molecular weight GO species as luminescent CNPs.

Nanochains (NCs) made up of a one-dimensional arrangement of magnetic nanoparticles (NPs) exhibit anisotropic properties with potential for various applications. Herein, using a novel self-assembly method we directly integrate single NCs onto desired substrates including devices. We present a nanoscopic analysis of magnetization reversal in 1D linear NP arrays by combining x-ray microscopy, magnetoresistance (MR), and micromagnetic simulations. Imaging the local magnetization along individual NCs by scanning transmission x-ray microscopy and x-ray magnetic circular dichroism under varying in situ magnetic fields shows that each structure undergoes distinct non-homogeneous magnetization reversal processes. The experimental observations are complemented by micromagnetic simulations, revealing that morphological inhomogeneities critically influence the reversal process where regions with parallel chains or larger multi-domain particles act as nucleation centers for the magnetization switching and smaller particles provide pinning sites for the domain propagation. Magnetotransport through single NCs reveals distinct MR behavior that is correlated with the unique magnetization reversal processes dictated by the morphology of the structures. This study provides new insights into the complex magnetization reversal mechanism inherent to one-dimensional particle assemblies and the effective parameters that govern the process.

To accurately achieve structure height differences in the range of single digit nanometres is of great importance for the fabrication of diffraction gratings for the extreme ultraviolet range (EUV). Here, structuring of silicon irradiated through a mask by a broad beam of helium ions with an energy of 30 keV was investigated as an alternative to conventional etching, which offers only limited controllability for shallow structures due to the higher rate of material removal. Utilising a broad ion beam allows for quick and cost effective fabrication. Ion fluence of the irradiations was varied in the range of 10¹⁶ ... 10¹⁷ ions · cm^-2. This enabled a fine tuning of structure height in the range of 1.00 ± 0.05 to 20 ± 1 nm, which is suitable for shallow gratings used in EUV applications. According to transmission electron microscopy investigations the observed structure shape is attributed to the formation of point defects and bubbles/cavities within the silicon. Diffraction capabilities of fabricated elements are experimentally shown at the SX700 beamline of BESSY II. Rigorous Maxwell solver simulation based on the finite-element method and rigorous coupled wave analysis are utilised to describe the experimental obtained diffraction pattern.

This study presents a detailed investigation into the fluorescence properties of color centers in single-crystal diamond needles (SCDNs) synthesized via chemical vapor deposition. Using steady-state and time-resolved photoluminescence (PL) techniques, we identified color centers with zero-phonon lines at 389 nm, 468 nm, 575 nm (NV⁰), 637 nm (NV^–), and 738 nm (SiV^–). PL excitation spectroscopy conducted at room temperature revealed the complex electronic structure of some of these centers, paving the way for further investigation into their fluorescence properties. Lifetime measurements were performed for each center, with the 389 nm one exhibiting the longest decay time (∼30 ns), which is advantageous for enhancing quantum coherence, improving photon emission efficiency, and reducing power consumption. Altogether, these findings highlight the potential of SCDNs for quantum applications and confirm their promise as a platform for next-generation photonic and quantum devices.

Zero-dimensional quantum dots (QDs) and their hybrid structures having been rapidly developed are reshaping the design and performance of next generation ultrafast electronic and optoelectronic devices. The high-performance metrics achievable in photodetectors, solar cells, transistors, and other application areas can be realized through the use of QDs with their tunable electronic and optical properties. Recent advances in the synthesis of QD hybrid structures, where QDs are incorporated within other nanostructure dimensions (1D nanowires, 2D materials), have dramatically increased charge carrier mobility, lowered recombination rates, and resulted in highly controlled interfacial properties. Synergistic effects between these hybrid configurations are exploited, including improved charge separation and enhanced exciton dissociation, which are very important for having ultrafast response times and greater sensitivity. Advanced fabrication techniques such as chemical vapor deposition and solution based self-assembly, QD hybrids can be fabricated with highly controlled interfaces and optimal energy band alignments. Further, computational simulations such as density functional theory (DFT) and time dependent DFT have provided further insights into the charge dynamics and electronic interactions in these hybrid systems for guidance on their design and application. The potential of QD-based hybrid architectures in addressing future information processing demands is demonstrated in this work, setting the stage for the development of high-speed, low-power devices in communications, sensing, and renewable energy technologies.