Two-dimensional semiconductors, and particularly MoS _2 , are promising active materials for room-temperature gas sensing devices because their channel conductance is strongly modulated by surface adsorption. Here we report a systematic study of the electrical transport properties of back-gated MoS _2 field-effect transistors (FETs) under controlled atmosphere and pressure. Transferred MoS _2 devices show stable n-type operation with a pronounced dependence of conductance, threshold voltage and hysteresis on ambient conditions, consistent with adsorption/desorption and trap dynamics at the MoS _2 /SiO _2 interface. To further clarify the microscopic kinetics underlying these macroscopic electrical variations, we performed low-frequency noise (LFN) measurements. This combined transport–noise approach provides access to microscopic fluctuation mechanisms that cannot be distinguished from conventional DC characterization alone. The spectra exhibit a 1/ ${f^{\;\gamma}}$ background and Lorentzian components whose characteristic frequencies are in the tens-of-hertz range (≈40–60 Hz) and at ∼2.0 kHz. The slow component shows thermally activated behavior with ${E_a} \approx 0.19{\text{ }}$ eV, consistent with physisorption-controlled dynamics, while the faster component is compatible with contact-related fluctuations. Measurements on CVD-grown MoS _2 FETs reproduce the same slow fluctuations, supporting the generality of the adsorption-driven process. Overall, this work establishes a solid transport baseline for MoS _2 FETs in controlled atmospheres and demonstrates that LFN spectroscopy provides a powerful tool to disentangle surface-adsorption kinetics from contact and interface effects.
Abstract Hybrid organic–inorganic perovskites are emerging as key materials for next-generation photodetectors, where the compositional and structural tunability and exceptional optoelectronic properties provide a powerful strategy to tune the microscopic mechanisms governing the photoresponse. Here, 3D MAPbI 3 and quasi-2D (PEA) 2 (MA)Pb 2 I 7 single-crystal photodetectors are comparatively investigated under dark and illuminated conditions. The devices employ two lateral Ag-paste contacts and therefore operate as photoconductors, in which illumination increases the crystal conductivity through the generation of mobile charge carriers under an applied bias. Both devices exhibit a nearly ohmic behavior in the dark and under illumination. The photocurrent increases almost linearly with the incident optical power, with a power-law exponentia of α ≈ 0.9 for both crystals. The 3D perovskite shows higher conductivity, with a dark current of 10 −10 A at V bias = 1 V, whereas the quasi-2D device exhibits a strongly suppressed dark current of 10 −12 A under the same bias condition. Prompt and reversible photocurrent switching is observed in both devices within the temporal resolution of the experimental setup; however, the 3D crystal also displays an additional slow current rise, suggesting the activation of a secondary light-induced process. Spectral measurements further reveal a widened bandgap in the quasi-2D perovskite, consistent with its layered structure. Overall, this comparative study highlights the key role of dimensionality and organic-cation engineering in balancing efficient photogeneration, dark-current suppression, and low-noise photodetection.
Manganese ferrite is gaining strong attention as an advanced material for environmental purification because of its intrinsic and extrinsic properties. As a photocatalyst it offers an effective near visible light band gap and active electron–hole transfer ability which supports the formation of reactive oxygen species for rapid degradation of aquatic pollutants. The material also exhibits excellent room temperature magnetic properties that enable easy recovery and reusability. However, MnFe _2 O _4 shows fast electron–hole recombination rate which limits its photocatalytic efficiency. This issue can be overcome by combining MnFe _2 O _4 with two-dimensional (2D) materials such as graphene, MoS _2 , MXene, g-C _3 N _4 , etc. These composites show significant improvement in catalytic activity, stability, reusability and visible light response. The hybrid structures form heterojunctions prevent faster recombination and the surface morphology provide more active surface sites for pollutant removal. These nanocomposites have demonstrated excellent performance in removing harmful metals including Cr(III), Cr(VI), Pb(II), Cd(II), As(III), As(V), etc as well as antibiotics such as norfloxacin, ciprofloxacin and tetracycline. They are also highly effective in degrading dyes such as methylene blue, methyl orange, rhodamine B and congo red and show strong antibacterial activity against both gram positive and gram negative species. This review highlights recent developments in the structure and synthesis of MnFe _2 O _4 and its 2D-nanocomposites and summarizes their adsorption capacity and photocatalytic efficiency. It also explains their pollution removal mechanisms and evaluates their reusability and practical potential studies. The study further discusses key research challenges including the need for improved stability prevention of metal leaching and scalable production for real wastewater treatment applications.
A theoretical model of double percolation in hybrid polymer nanocomposites reinforced with carbon nanotubes (CNTs) and aramid nanofibers (ANFs) is proposed. The model is based on the excluded-volume concept and a mean-field description of network connectivity. An analytical expression describing the effective connectivity of the hybrid system was derived by considering CNT–CNT, ANF–ANF, and CNT–ANF interactions. The proposed approach demonstrates that the formation of a continuous transport network is governed not only by the individual percolation behavior of each filler type, but also by hybrid interactions between dissimilar nanostructures. The model predicts that ANFs can promote network formation at reduced CNT concentrations through the development of hybrid CNT–ANF contacts. Theoretical concentration maps, scaling dependences, and parametric analyses were constructed to investigate the influence of filler composition and hybrid interaction probability on network connectivity. The obtained results provide a theoretical framework for describing double-percolation phenomena and transport network formation in hybrid polymer nanocomposites.
Rapid and reliable detection of bacterial pathogens is essential for clinical diagnostics and food safety monitoring. This study explores bacterial outer membrane vesicles (OMVs), nanoscale particles naturally released by Gram-negative bacteria such as Escherichia coli , as diagnostic surrogates for intact cells. An E. coli -specific aptamer was conjugated to indium phosphide–zinc sulphide quantum dots to evaluate its ability to recognise vesicles derived from the bacterial outer membrane. Optical measurements together with high-resolution transmission electron microscopy confirmed aptamer-mediated binding of the quantum dot-aptamer conjugates to these vesicles. To investigate biosensing performance, the same aptamer was immobilised on gold electrodes and vesicle recognition was monitored using electrochemical impedance measurements. The resulting sensor showed a concentration-dependent increase in interfacial charge-transfer resistance across a vesicle concentration range of $10^7-10^9$ vesicles/ml and demonstrated strong selectivity towards E. coli -derived vesicles compared with those from Pseudomonas aeruginosa . These findings demonstrate that aptamer-functionalised nanomaterials can selectively target bacterial OMVs and highlight their potential as stable biomarkers for vesicle-based bacterial detection platforms.
The discovery of two-dimensional materials has revolutionized condensed matter physics, with transition metal dichalcogenides (TMDCs) offering tunable electronic and optical properties. Monolayer tungsten diselenide WSe $_2$ , a direct bandgap semiconductor with strong excitonic effects, is especially promising for optoelectronics. When two WSe $_2$ monolayers are stacked with controlled twisting angles, the resulting twisted bilayer (tB) material forms a moiré superlattice that significantly modifies its electronic structure and optical response through interlayer coupling and band reconstruction. In a systematic study employing photoluminescence (PL) and differential micro-reflectance contrast ( $\mu$ RC) spectroscopy and supported by first-principles calculations, we investigate the optical properties of tB WSe $_2$ for twisting angles $ 0^\circ \lt \theta \lt 60^\circ $ . Excitonic peaks (A, B, C, D) exhibit angle-dependent energy shifts. Notably, A and C excitons show characteristic energy splittings that reflect twisting-angle-modulated interlayer hybridization and spin–orbit coupling effects. The A exciton shows local minima at $0^\circ$ and $60^\circ$ , and a maximum near $30^\circ$ . This pattern reflects variations in interlayer hybridization—stronger coupling at $0^\circ$ and $ 60^\circ$ , weaker at intermediate angles—consistent with moiré-induced modifications. Our work reveals the periodic modulation of exciton energies in WSe $_2$ homo-bilayers across a wide range of twisting angles, directly linking these variations to interlayer coupling strength and spin–orbit splitting. Our findings provide clear experimental–theoretical consistency, identifying the twisting angle as an effective tuning knob for excitonic transitions and interlayer interactions in TMDC bilayers. The work contributes to the understanding of the structure–property relationships in twisted TMDC materials, and the results may lead to new design principles for next-generation, moiré-engineered optoelectronic and quantum devices.
In this paper, we describe plasmonic sensors based on two dimensional (2-D) periodic arrays of aluminum nanopillars having narrow gaps between the plasmonic nanostructures, such that these sensors operate in the ultra-violet (UV) spectral regime (200–400 nm). Employing finite difference time domain (FDTD) simulations, we design highly efficient plasmonic sensors exhibiting high bulk and localized sensitivities in the UV spectral regime. Aluminum has been taken as the plasmonic metal in our simulations as nanostructures of aluminum have plasmon resonance wavelength tuned in the UV spectral regime. A thin layer of aluminum oxide (Al _2 O _3 ) is generally formed on the surface of the aluminum nanopillars due to oxidation. In order to capture the oxidation on the surface of the aluminum nanostructures, we have taken a 2–3 nm layer of Al _2 O _3 on the surface of the nanostructures in all the FDTD simulations performed in this paper. In our FDTD simulations, we optimize the heights, widths, periodicities in the x - and y - directions, and the aspect ratios of the aluminum nanopillars, as well as the thickness of the oxide layer to ensure that the plasmon resonance wavelengths in the reflectance spectra for these nanostructures lie in the UV spectral regime, so that these optimized nanostructures could be employed for plasmonic sensing in the UV spectral regime. The shifts in the reflectance spectra, and in particular the plasmon resonance wavelengths, with a change in the bulk as well as localized refractive indices around the plasmonic nanostructures were calculated to determine the bulk and localized sensitivities of these sensors. Employing FDTD simulations, we demonstrate that the proposed plasmonic sensors can be employed for bulk sensing of glucose, and localized sensing of bio molecules (proteins, DNA etc) in the UV spectral regime.We observe that plasmonic sensors operating the UV spectral regime that were based on 2D periodic arrays of aluminum nanopillars had a much higher bulk and localized sensitivities than those based on 1D periodic arrays of aluminum nanowires. We also studied the effect of rounding of edges and corners of the nanopillars on the sensitivities of these sensors. We also observe that the 2D periodic arrays of aluminum nanopillars are significantly less polarization dependent as compared to 1D periodic arrays of aluminum nanowires.
Abstract Green synthesis pathways play a vital role in the fabrication of metal nanoparticles. The present study focuses on an environmentally benign strategy for the synthesis of copper nanoparticles (CuNPs) using Justicia adhatoda leaf extract. The phytochemical constituents of the J. adhatoda extract effectively mediated the reduction of Cu²⁺ ions and also acted as stabilizing agents. The successful formation of CuNPs was confirmed by UV–Visible spectroscopy through the appearance of a surface plasmon resonance (SPR) band at 348 nm. Morphological analysis using SEM and TEM revealed predominantly spherical CuNPs with particle sizes in the range of 31–54.2 nm and 40–47 nm, respectively. AFM analysis further confirmed the smooth surface topography and effective bio-capping of the synthesized CuNPs. The biosynthesized CuNPs demonstrated excellent catalytic efficiency toward methylene blue dye, achieving more than 90% degradation. Furthermore
Abstract Mg 0.5 Cu 0.5 Fe 2 O 4 nanoferrites were synthesized via a sol–gel auto-combustion route using ammonia as a pH-modulating agent. The precursor nitrate–citrate solution was adjusted to pH 3, 7, and 11 to systematically investigate the influence of reaction environment on structural evolution and photocatalytic performance. Phase purity and structural features were examined by x-rays diffraction with Rietveld refinement, while energy dispersive x-ray analysis, scanning electron microscopy, FTIR, and UVis-DRS analyses were employed to evaluate compositional, morphological, and optical characteristics, respectively. The results reveal that pH significantly impacts the cation distribution, crystallite size and morphology. The samples prepared at pH 3 and 7 exhibit mixed spinel configurations, whereas the pH 11 specimen approaches an inverse spinel arrangement. A monotonic increase in average particle size was observed with increasing pH, from 47 nm (pH 3) to 67 nm (pH 7) and 73 nm (pH 11), indicating enhanced grain growth under alkaline conditions. Photocatalytic activity was assessed using a 20 ppm phenol red solution, in which 25 mg of nanoferrite catalyst was dispersed, and the degradation under solar irradiation in the presence of H₂O₂ was monitored. The pH 3 nanoferrite exhibited superior performance, achieving 92% degradation efficiency with 50 mM H₂O₂. The enhanced activity is attributed to optimized cation distribution, reduced particle size, and improved charge carrier dynamics. These findings demonstrate that pH engineering is an effective strategy to tailor the structural and functional properties of Mg–Cu ferrite nanocatalysts.
Abstract In this study we have investigate the systematic synthesis, characterization, and electrochemical study of Ti 3 C 2 T x /NiFe 2 O 4 nanocomposite electrodes for high-performance Quasi-Solid-State supercapacitor applications. The study explores the synergistic effects arising from the strategic integration of two-dimensional Ti 3 C 2 T x MXenes nanosheets with pseudocapacitive NiFe 2 O 4 nanoparticles to overcome the individual limitations of each component while maximizing their complementary advantages. Through systematic variation of NiFe 2 O 4 loading weight percentages (5%, 20%, 50%, and 80%), the optimal composition was identified as Ti 3 C 2 T x NiFe 2 O 4 @20% (MNFO20), which demonstrated exceptional electrochemical performance characteristics. Comprehensive electrochemical characterization employing cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy revealed that the MNFO20 nanocomposite achieved a remarkable specific capacitance of 242 F g −1 at 10 mV s −1 , as compared to pristine MXenes (68 F/g). The nanocomposite exhibited superior energy density of 57.76 Wh kg −1 and power density of 799.84 W kg −1 . Mechanistic analysis revealed that the enhanced performance originates from synergistic effects including the formation of efficient electron transport networks, complementary charge storage mechanisms combining electrical double-layer capacitance and pseudocapacitance, prevention of MXenes layer restacking, and improved electrolyte accessibility. The charge transfer resistance was dramatically reduced from 2.25 Ω for pristine MXenes to 0.14 Ω for the MNFO20 composite, demonstrating significantly improved charge transfer kinetics. It also maintains 86.2% of its initial capacity over 2000 cycles. These findings establish Ti 3 C 2 T x /NiFe 2 O 4 nanocomposites as promising electrode materials for next-generation energy storage devices requiring both high energy density and rapid power delivery capabilities.
Abstract Bone defect is a great challenge in the field of orthopedics due to the limited self-healing ability of bone tissue and the insufficient supply of bone grafts. Polymethyl methacrylate (PMMA) is extensively utilised in bone cement and its modification has garnered considerable attention to enhance improve its biological functionality. We prepared the PMMA-loaded strontium ranelate (SR) termed aSR@PMMA. It was co-cultured with osteoblasts and bone marrow mesenchymal stem cells, and its biocompatibility and anti-inflammatory properties were assessed using the CCK-8 assay, Live/Dead staining and IL-1β ELISA . The osteogenic induction capacity of the material was evaluated by detecting the expression of osteogenisis-related genes (BSP/OCN) through Western blot (WB) and Real-Time Quantitative PCR (RT-qPCR). To explore the potential pro-osteogenesis mechanism of SR@PMMA, the material was implanted into a rat femoral defect model, followed by collection of the repaired bone tissue for proteomic analysis and bioinformatics analysis. Furthermore, the study validated the related mechanisms by determining the levels of relatived metabolites, including Reactive Oxygen Species (ROS), Nicotinamide Adenine Dinucleotide (NAD+/NADH), and lactic acid.In the CCK-8 assay, live-dead cell staining and IL-1β ELISA, the SR@PMMA showed great biocompatibility and anti-inflammatory potential. The RT-qPCR and WB assay indicated that the SR@PMMA facilitates osteogenesis by regulating the expression of BSP and OCN. In accordance with the rat implantation model, the proteomic analysis combined with bioinformatic analysis showed that the SR@PMMA may potentially regulate lactate dehydrogenase (LDHB) to increase lactic acid level and suppress oxidative stress synthesis. The present study presented a novel SR@PMMA bone cement with great biocompatibility, anti-inflammation potential and pro-osteogenesis capacity. A proteomic and bioinformatic analysis was conducted to elucidate the biological mechanisms underlying the regulatory function of SR@PMMA on LDHB-mediated metabolic flux alterations, with the objective of mitigating intracellular oxidative stress and thereby promoting bone regeneration.
Metallic nanoparticles are one of the key compounds that make a tremendous application in biological fields. Copper and Copper based nano-moiety is one of the leading metallic nanoparticles, which exhibit different aspects of biological and chemical applications. In this paper, the authors endeavoured to review Copper and Copper based nanoparticles, their synthesis, and biological and chemical applications, especially emphasising, antimicrobial, anticancer, antioxidant, pharmacological, catalytic activity and in pollution management. The Cu/CuONPs are measured and characterized by various modern techniques like x-ray diffraction, atomic force microscopy, x-ray photoelectron spectroscopy, scanning electron microscope, nuclear magnetic resonance, Fourier transform infrared spectroscopy, transmission electron microscope and many more techniques such as DTA-TGA (Differential Thermal Analysis, Thermogravimetric Analysis), NTR (nanoparticle tracking analysis) etc. In Biological synthesis, CuNPs have been synthesized with various kinds of bacteria, algae, leaf, and flower extracts which further showed various unexpected biological and chemical applications. In Chemical synthesis, these nanoparticles were formulated under various chemical processes like thermal decomposition, wet chemical methods, sol–gel method etc having some satisfactory outcomes each time. On the other hand, the Cu/CuONPs mediated anti-microbial activity showed great results that these nanoparticles will be next-generation drugs for mankind. Their vast applications against selected human ( Salmonella typhimurium, Shigella flexneri etc ), fish and bacterial pathogens have also been discovered during the research over the time period (such as Vibrio alginolyticus, Vibrio parahaemolyticus, Aeromonas hydrophila etc ). Copper Nanoparticles have also shown extraordinary results by performing a catalytic activity in the synthesis of different molecules as these are highly active in nature. Copper-based nanoparticles, like CuNPs, CuO NPs, and bioengineered nanocomposites, have strong anticancer effects that depend on their concentration also and overwhelming action against many types of human cancer cell lines. Studies reported Copper-based nanoparticles and nanocomposites showing positive results in pharmacological fields and pollution management.
Cadmium remains a significant threat to environmental sustainability and public health, driving the demand for efficient and sustainable treatment technologies. In this study, a diethylenetriaminepentaacetic acid-chitosan-modified silica aerogel (DCS) nanocomposite was successfully synthesized and systematically evaluated for Cd2+ removal from aqueous solutions. The introduction of DTPA and chitosan endowed the aerogel framework with abundant chelating functional groups while retaining the intrinsic advantages of silica aerogels. Structural and morphological analyses confirmed the formation of a stable three-dimensional porous nanostructure with a high specific surface area, uniform morphology, and improved accessibility of active adsorption sites, resulting in a markedly enhanced affinity toward Cd2+ ions. Thermodynamic analysis revealed that the adsorption process is exothermic, with a calculated enthalpy value (Delta H degrees) of-47.320 kJ mol-1, indicating that Cd2+ uptake is more favorable at lower temperatures. Kinetic studies showed that the adsorption behavior follows a pseudo-second-order model, suggesting that chemisorption via surface complexation dominates the removal mechanism. Equilibrium data were best described by the Langmuir isotherm, implying monolayer adsorption on a homogeneous surface, with a maximum adsorption capacity of 38.461 mg g-1. Under optimized conditions, this nanocomposite achieved a Cd2+ removal efficiency of approximately 95%, nearly three times higher than that of unmodified silica aerogel. Importantly, the nanocomposite exhibited excellent structural stability and adsorption performance over multiple reuse cycles. These results highlight the effectiveness of rational surface functionalization in tailoring aerogel-based nanomaterials and demonstrate the strong potential of the DCS nanocomposite as a functional nano-adsorbent for advanced water purification and environmental nanotechnology applications.
This study presents the green synthesis of ZnO/Cu 2 O hybrid nanomaterials derived from Mentha Spicata (Mint) leaf aqueous extract, employed as an eco-friendly reducing agent, targeting electrocatalytic oxygen evolution reaction (OER) applications. The crystalline nature of the synthesized Mentha Spicata leaf of ZnO/Cu 2 O (MCZ) hybrid nanomaterials was systematically analyzed using X-ray diffraction (XRD). Detailed structural and morphological characterizations, including XRD, Attenuated Total Reflectance Fourier-transform infrared spectroscopy (ATR-FTIR), Raman spectroscopy, and Field Emission Scanning Electron Microscopy with Energy-Dispersive X-ray spectroscopy (FESEM-EDX), confirmed the successful fabrication of well-defined crystalline hybrid nanostructures. When implemented as electrocatalysts on carbon paper electrodes in alkaline medium (1 M KOH), the biogenically synthesized MCZ hybrid nanomaterials exhibited superior OER catalytic activity, achieving a low overpotential of 263.4 mV to reach a current density of 10 mA cm −2 at a scan rate of 10 mV s −1 , compared to ZnO, Cu 2 O and benchmark catalyst IrO 2. The catalysts demonstrated a turnover frequency (TOF) of 0.022 s −1 at 1.55 V versus the reversible hydrogen electrode (RHE), coupled with outstanding long-term operational stability. These findings underscore the efficacy of the bio-assisted synthetic methodology for fabricating sustainable, high-performance electrocatalysts suitable for efficient overall water splitting.
Green-emitting carbon dots (CDs) were synthesized via a solvent-free, vacuum-assisted method using citric acid and urea. The CDs exhibited strong photoluminescence and served as selective, sensitive probes for Cu 2+ detection in water, with a detection limit of 26 nM. Among the tested metal ions, Cu 2+ induced the most significant PL quenching. Time-resolved photoluminescence measurements of the CDs in the presence of Cu 2+ ions revealed a minimal change in lifetime, despite a significant decrease in PL intensity, along with unchanged UV–vis absorption, indicating a mixed quenching mechanism. The sensor’s applicability was confirmed in raisin extract and tea infusion, showing notable PL suppression. With their simplicity, selectivity, and sensitivity, these CDs offer promising potential as nanosensors for detecting Cu 2+ in environmental and real-world analytical settings.
SiO2/Mo/SiO2/Si antireflection substrates were investigated for optical visualization of transparent ultrathin films. By tuning layer thicknesses, the structure can produce either a V-shaped reflectance spectrum, reaching zero at a specific wavelength, or a broadly low-reflectance spectrum with reflectance below 1% across 450-700 nm. These substrates help study how the slope of V-shaped reflectance affects visualization. Analysis revealed that for broadly low-reflectance substrates, adjusting the top SiO2 layer thickness maintains the contrast spectrum sign across the visible range. Experiments using monolayer graphene oxide, presented as a representative transparent ultrathin film, demonstrate that optical imaging under white-light illumination can be achieved without the use of narrow band-pass filters.
Inverse design approaches based on deep learning have recently shown strong potential in accelerating the development of nanophotonic devices. In this work, we investigate the capability of a tandem neural network combined with a genetic algorithm (GA) to design multilayer nanophotonic color splitter structures with improved optical performance. The objective of this study is to explore how far extrapolative designs can be generated when increasing the structural complexity while starting with a relatively small training dataset. The proposed framework was first implemented to generate two-layer color splitter structures capable of directing red, green and blue wavelengths to their corresponding pixel regions in a CMOS image sensor. The generated designs were evaluated using two figures of merit, sensitivity and selectivity. For the two-layer structures the combined GA tandem network approach demonstrated the extrapolative design capability. The framework was then extended to generate three-layer color splitter structures to further examine the impact of increased structural complexity. While the three-layer network successfully generated interpolative structures, it was not able to consistently exceed the performance of the training dataset due to the increased complexity of the design space and limitations in forward model prediction outside the training region. To validate the practical feasibility of the proposed approach, selected single-layer and two-layer structures were fabricated using two-photon lithography and experimentally characterized. The measured optical responses show good qualitative agreement with the simulated results and confirm the predicted RGB focusing behavior. These results demonstrate the capability of the proposed framework to generate fabricable nanophotonic color splitter designs and provide insights into the limitations and opportunities of deep learning based inverse design for increasingly complex multilayer nanophotonic color splitter structures.
Ultrathin Ti3C2Tx MXene is a good material for high-performance thin-film transistors (TFTs) because its work function may be changed and it has conductivity that is close to that of metals. However, interfacial charge trapping and dielectric compatibility continue to hides its true potential. This work introduces a method that combines fluoride-free molten-salt-synthesized Ti3C2Tx MXene, which has better material quality and fewer defects during synthesis, with ultraclean interface engineering using atomic-layer-deposited high-kappa Li-Al2O3 dielectric and heavily p(+)-doped silicon substrate. The resulting TFTs exhibit enhanced field-effect mobility (similar to 25 cm(2) V-1 s(-1)), low subthreshold swing (similar to 61 Mv dec(-1)), (close to the thermionic limit), minimal hysteresis, and strong stability at low voltage to enhance electrical performance. The platform also improves NH3 gas sensing, allowing it to be detected at ambient temperature. The study emphasizes interface engineering and dielectric optimization for MXene-based device performance and offers a scalable path for next-generation low-power electronics and sensing.
The development of localized surface plasmon resonance biosensors is typically limited to inefficient trial-and-error design strategies and reliance on existing generic plasmonic nanostructures that fail to tailor the evanescent field to the specific properties of the bioassay. This work presents an automated design workflow which combines finite-difference time-domain simulations with a simplicial homology global optimization algorithm to systematically maximize the surface refractive index sensitivity (SRIS) of a plasmonic nanopillar structure. This combined approach allows to identify a nanostructure geometry with an electromagnetic decay length closely aligned with the hydrodynamic radius of the bioassay in use. As an example, we apply the concept to a sensor for the detection of the anti-inflammatory drug diclofenac. The improved nanostructure design was fabricated via electron beam lithography and replicated using soft UV-nanoimprint lithography. The fabricated improved sensor substrates were experimentally validated using a standardized layer-by-layer deposition of polyelectrolytes (PAH/PSS), demonstrating a significant sensitivity improvement compared to baseline structures used in previous work. The experimental validation confirms an 80% increase in SRIS (from 134.1 +/- 5.3 nm RIU-1 to 245.8 +/- 10.1 nm RIU-1). Application of the competitive DCF immunoassay on the optimized geometry remains subject of future work.
