Search Results (758)

This paper aims to enhance the sensitivity of fiber-optic surface plasmon resonance (SPR) sensors by innovatively applying TRIZ (Theory of Inventive Problem Solving). To identify the key challenges faced by current SPR sensors, methods such as functional analysis, causal analysis, and the Nine-Window method are employed. Utilizing TRIZ tools, including Technical Contradiction, Physical Contradiction, the Smart Little Man method, and object–field analysis, innovative solutions are proposed, involving transparent indium tin oxide (ITO) thin films, an asymmetric photonic crystal fiber structure with elliptical pores, and titanium dioxide (TiO₂) thin films. Experimental results reveal a significant improvement in sensitivity, with an average of 9961.90 nm/RIU and a peak of 12,503.56 nm/RIU within the refractive index range of 1.33061 to 1.40008, representing a 456% increase compared to the original gold-film fiber-optic SPR sensor. These findings have potential applications in biosensing, environmental monitoring, and food safety. Full article

Flexible polymer-based piezoelectric nanogenerators (PENGs) have gained significant interest due to their ability to deliver clean and sustainable energy for self-powered electronics and wearable devices. Recently, the incorporation of fillers into the ferroelectric polymer matrix has been used to improve the relatively low piezoelectric properties of polymer-based PENGs. In this study, we investigated the effect of various nanofillers such as titania (TiO₂), zinc oxide (ZnO), reduced graphene oxide (rGO), and lead zirconate titanate (PZT) on the PENG performance of the nanocomposite thin films containing the nanofillers in poly(vinylidene fluoride-co-trifluoro ethylene) (P(VDF-TrFE)) matrix. The nanocomposite films were prepared by depositing molecularly thin films of P(VDF-TrFE) and nanofiller nanoparticles (NPs) spread at the air/water interface onto the indium tin oxide-coated polyethylene terephthalate (ITO-PET) substrate, and they were characterized by measuring their microstructures, crystallinity, β-phase contents, and piezoelectric coefficients (d₃₃) using SEM, FT-IR, XRD, and quasi-static meter, respectively. Multiple PENGs incorporating various nanofillers within the polymer matrix were developed by assembling thin film-coated substrates into a sandwich-like structure. Their piezoelectric properties, such as open-circuit output voltage (V_OC) and short-circuit current (I_SC), were analyzed. As a result, the PENG containing 4 wt% PZT, which was named P-PZT-4, showed the best performance of V_OC of 68.5 V with the d₃₃ value of 78.2 pC/N and β-phase content of 97%. The order of the maximum V_OC values for the PENGs of nanocomposite thin films containing various nanofillers was PZT (68.5 V) > rGO (64.0 V) > ZnO (50.9 V) > TiO₂ (48.1 V). When the best optimum PENG was integrated into a simple circuit comprising rectifiers and a capacitor, it demonstrated an excellent two-dimensional power density of 20.6 μW/cm² and an energy storage capacity of 531.4 μJ within 3 min. This piezoelectric performance of PENG with the optimized nanofiller type and content was found to be superior when it was compared with those in the literature. This PENG comprising nanocomposite thin film with optimized nanofiller type and content shows a potential application for a power source for low-powered electronics such as wearable devices. Full article

MnO_x thin films with silver additives were electrochemically deposited on an Indium Tin Oxide (ITO) substrate with silver acetate and potassium permanganate aqueous solution. The addition of Ag enhanced electrochromic behavior during cyclic voltammetry (CV). The morphology of the thin films was examined by using scanning electronic microscopy (SEM) and transmission electron microscopy (TEM). The chemical states of Mn and Ag ions on the surfaces of the thin films were examined using X-ray photoelectron spectroscopy (XPS). Spherical Ag₂O and Ag nanoparticles were homogeneously dispersed on the thin films. The electrochemistry of the thin films was examined by cyclic voltammetry in a conventional three-electrode system and an electrochemically tested system. The electrochromic behavior of the films was demonstrated through the cyclic voltammetry (CV) process in the KNO₃ electrolyte. The electrochromic behavior of the thin films depended on the redox reactions associated with the reaction between Ag and Ag₂O coupled with Mn⁴⁺ ions and Mn³⁺ ions in the KNO₃ electrolyte. Full article

The compatibility of low infrared emission and wideband microwave absorption has drawn extensive attention, both theoretically and practically. In this paper, an infrared–radar-compatible stealth metasurface is designed using transparent conductive materials, namely indium tin oxide (ITO) and poly methacrylimide (PMI). The designed structure is a combination of a radar-absorbing layer (RAL) and a low-infrared-emission layer (IRSL), with an overall thickness of about 1.7 mm. It consists of three layers, a top-layer patch-type ITO frequency-selective surface, an intermediate layer of a four-fold rotationally symmetric ITO patterned structure, and a bottom reflective surface. The layers are separated by PMI. Simulation results show that the structure achieves over 90% broadband absorption in the microwave band from 7 to 58 GHz and low emissivity of 0.36 in the infrared band. In addition, due to the four-fold rotationally symmetric design, the structure also exhibits polarization insensitivity and excellent angular stability. Therefore, the designed structure possesses ultra-broadband radar absorption performance, low infrared emissivity, and polarization-insensitive properties at a thin thickness, and has a promising application in the field of multi-band-compatible stealth technology. Full article

Monitoring and forecasting air quality is essential for public health and environmental management. It details the air’s cleanliness, pollution levels, and any related health risks that the general public may find concerning. This research investigates how effective machine learning techniques and particle swarm optimization are in predicting air quality. An array of machine learning algorithms, including XGBoost, support vector regression, linear regression, and random forest, was selected to ensure effective modeling outcomes. The models were trained on an open access dataset and performed performance evaluation. The answers from an on-site gas multisensor device in an Italian city were included in the dataset. The findings from the dataset were shown to accurately model and predict environmental factors affecting air quality (e.g., air temperature, humidity, indium oxide, tin oxide, NO_x, NO₂, etc.) using real-world air quality data. The experiments were repeated by optimizing the relevant machine learning methods with PSO. PSO is a metaheuristic optimization method widely used in feature selection and feature extraction processes. The metrics MAE, MSE, RMSE, and R², commonly used to evaluate regression algorithms, were utilized to assess the models’ performances. Particle swarm optimization-based support vector regression performed best, with MAE, MSE, RMSE, and R² values of 0.071, 0.015, 0.122, and 0.999, respectively. In addition, Shapley additive explanations (SHAP) analysis was performed to show which feature of the PSO-based SVR model was practical and to what extent. The results show that the proposed model successfully predicts air quality. Full article

In this study, four various titanium dioxide/cuprum oxide (TiO₂/Cu_xO) photovoltaic structures deposited on glass/indium tin oxide (ITO) substrates using the direct-current (DC) reactive magnetron sputtering technique were annealed in air. In our previous work, the deposition parameters for different buffer layer configurations were first optimized to enhance cell fabrication efficiency. In this paper, the effects of post-deposition annealing at 150 °C in air on the optical properties and I-V characteristics of the prepared structures were examined. As a result, significant changes in optical properties and a meaningful improvement in performance in comparison to unannealed cells were observed. Air annealing led to an increase in the reflection coefficient of the TiO₂ layer for three out of four structures. A similar increase in the reflection of the Cu_xO layer occurred after heating for two out of four structures. Transmission of the TiO₂/Cu_xO photovoltaic structures also increased after heating for three out of four samples. For two structures, changes in both transmission and reflection resulted in higher absorption. Moreover, annealing the as-deposited structures resulted in a maximum relative increase in open-circuit voltage (V_oc) by 294% and an increase in short-circuit current (I_sc) by 1200%. The presented article gives some in-depth analysis of these reported changes in character and origin. Full article

Indium tin oxide (ITO) is a commonly used material for transparent conductive electrodes (TCE) in optoelectronic applications. On the other hand, graphene has superior electrical conductivity and exceptional mechanical flexibility, which makes it a promising candidate as a TCE material. This work proposes a CVD graphene/ITO hybrid electrode enhanced by doping with silver nanowires (Ag-NWs). The study aims to improve the performance of the electrode by optimizing two key parameters during the fabrication process: the thermal annealing time after the transfer of graphene on ITO and the Ag-NWs doping conditions. The annealing treatment is fundamental to reducing the residues on the surface of graphene and increasing the interface contact between graphene and ITO. The correct coverage and distribution of the dopant on graphene is obtained by controlling the concentration of the Ag-NWs and the spin coating speeds. The results indicate a substantial improvement in the optical and electrical performance of the Ag-NWs/graphene/ITO hybrid electrode. A remarkably low sheet resistance of 42.4 Ω/sq (±2 Ω/sq) has been achieved while maintaining a high optical transmittance of 87.3% (±0.5%). Full article

Homogeneous aptasensors that eliminate the need for probe labeling or immobilization hold significant potential for the rapid detection of tumor biomarkers. Herein, a homogeneous aptasensor with electrochemical (EC) and electrochemiluminescence (ECL) dual detection channels was developed by integrating nanochannel-based probe enrichment and DNase I cleavage for selective detection of the tumor biomarker, carbohydrate antigen 125 (CA125). A two-dimensional (2D) composite probe was prepared by assembling the CA125-specific aptamer and the cationic probe tris(2,2′-bipyridyl)Ru(II) (Ru(bpy)₃²⁺), which exhibited both EC and ECL properties, onto graphene oxide (GO) nanosheets (Ru(bpy)₃²⁺/Apt@GO). A vertically ordered mesoporous silica film (VMSF) with ultrasmall, uniform, and vertically aligned nanochannel arrays was rapidly grown on the inexpensive and disposable indium tin oxide (ITO) electrode, forming the detection interface. Due to the size exclusion effect of the ultrasmall nanochannels in VMSF, the Ru(bpy)₃²⁺/Apt@GO probe was unable to penetrate the nanochannels, resulting in no detectable Ru(bpy)₃²⁺ signal on the electrode. Upon specific recognition of CA125 by the aptamer, an aptamer-CA125 complex was formed and subsequently detached from GO. DNase I then cleaved the aptamer-CA125 complex, releasing CA125 and allowing Ru(bpy)₃²⁺ to dissociate into the solution. This enzymatic cleavage enabled CA125 to re-enter the binding cycle, amplifying the release of Ru(bpy)₃²⁺ into the solution. The electrostatic adsorption of the cationic Ru(bpy)₃²⁺ by VMSF significantly enhanced both the EC and ECL signals. The constructed aptasensor exhibited a linear EC detection range for CA125 from 0.1 U/mL to 100 ng/mL, with a limit of detection (LOD) of 91 mU/mL. For ECL detection, CA125 was detected over a range from 0.001 to 100 U/mL, with a LOD as low as 0.4 mU/mL. The developed aptasensor demonstrated excellent selectivity and was successfully applied to the dual-mode EC/ECL detection of CA125 in fetal bovine serum samples. Full article

This paper presents a novel microfluidic device that integrates dielectrophoresis (DEP) forces with a membrane filter to concentrate and trap microparticles in a narrow region for enhanced optical analysis. The device combines the broad particle capture capability of a membrane filter with the precision of DEP to focus particles in regions optimized for optical measurements. The device features transparent indium tin oxide (ITO) top electrodes on a glass substrate and gold (Au) bottom electrodes patterned on a small area of the membrane filter, with spacers to control the gaps between the electrodes. This configuration enables precise particle concentration at a specific location and facilitates real-time optical detection. Experiments using 0.8 μm fluorescent polystyrene (PS) beads and Escherichia coli (E. coli) bacteria demonstrated effective particle trapping and concentration, with fluorescence intensity increasing proportionally to particle concentration. The application of DEP forces in a small region of the membrane filter resulted in a significant enhancement of fluorescence intensity, showcasing the effectiveness of the DEP-enhanced design for improving particle concentration and optical measurement sensitivity. The device also showed promising potential for bacterial detection, particularly with E. coli, by achieving a linear increase in fluorescence intensity with increasing bacterial concentration. These results highlight the device’s potential for precise and efficient microparticle concentration and detection. Full article

The sensitive detection of inflammatory biomarkers in gingival crevicular fluid (GCF) is highly desirable for the evaluation of periodontal disease. Luminol-based electrochemiluminescence (ECL) immunosensors offer a promising approach for the fast and convenient detection of biomarkers. However, luminol’s low ECL efficiency under neutral conditions remains a challenge. This study developed an immunosensor by engineering an immunorecognition interface on the outer surface of mesoporous silica nanochannel film (SNF) and confining a Co₃O₄ nanocatalyst within the SNF nanochannels to improve the luminol ECL efficiency. The SNF was grown on an indium tin oxide (ITO) electrode using the simple Stöber solution growth method. A Co₃O₄ nanocatalyst was successfully confined within the SNF nanochannels through in situ electrodeposition, confirmed by X-ray photoelectron spectroscopy (XPS) and electrochemical measurements. The confined Co₃O₄ demonstrated excellent electrocatalytic activity, effectively enhancing luminol and H₂O₂ oxidation and boosting the ECL signal under neutral conditions. Using interleukin-6 (IL-6) as a proof-of-concept demonstration, the epoxy functionalization of the SNF outer surface enabled the covalent immobilization of capture antibodies, forming a specific immunorecognition interface. IL-6 binding induced immunocomplex formation, which reduced the ECL signal and allowed for quantitative detection. The immunosensor showed a linear detection range for IL-6 from 1 fg mL⁻¹ to 10 ng mL⁻¹, with a limit of detection (LOD) of 0.64 fg mL⁻¹. It also demonstrated good selectivity and anti-interference capabilities, enabling the successful detection of IL-6 in artificial GCF samples. Full article

This study investigates the structural, optical, and photocatalytic properties of cadmium oxide (CdO) nanoparticles (NPs) and indium–tin oxide (ITO)-doped CdO NPs. The synthesis of CdO NPs and ITO NPs was accomplished through the co-precipitation method. Scanning electron microscopy (SEM) analysis indicates that pure CdO NPs exhibit agglomerated structures, whereas ITO doping introduces porosity and roughness, thereby improving particle dispersion and facilitating electron transport. Energy dispersive spectroscopy (EDS) corroborates the successful incorporation of tin (Sn) and indium (In) within indium–tin oxide (ITO)-doped cadmium oxide (CdO) nanoparticles (NPs) in addition to cadmium (Cd) and oxygen (O). X-ray diffraction (XRD) analysis demonstrates that an increase in ITO doping results in a reduction of the crystallite size, decreasing from 23.43 nm for pure CdO to 18.42 nm at a 10% doping concentration, which can be attributed to lattice distortion. Simultaneously, the band gap exhibits a narrowing from 2.92 eV to 2.52 eV, achieving an optimal value at 10% ITO doping before experiencing a slight increase at higher doping concentrations. This tuneable band gap improves light absorption, which is crucial for photocatalysis. The photocatalytic degradation of rhodamine B (RhB) highlights the superior efficiency of ITO-doped CdO nanoparticles, achieving a remarkable 94.68% degradation under sunlight within 120 min, up 81.01%, significantly surpassing the performance of pure CdO. The optimal RhB concentration for achieving maximum degradation was determined to be 5 mg/L. This enhanced catalytic activity demonstrates the effectiveness of ITO-doped CdO NPs under both UV and visible light, showcasing their potential for efficient pollutant degradation in sunlight-driven applications. Full article

Transparent conductive oxides are essential materials for many optoelectronic applications. For new devices for aerospace and space applications, it is crucial to know how they respond to the space environment. The most important issue in commonly used low-Earth orbits is proton radiation. This study examines the effects of high-energy proton irradiation (226.5 MeV) on thin films of aluminium-doped zinc oxide (AZO) and indium tin oxide (ITO). We use X-ray diffraction and electron microscopy observations to see the changes in the structure and microstructure of the films. The optical properties and homogeneity of the materials are determined by spectrophotometry and spectroscopic ellipsometry (SE). Analysis of the chemical states of the elements with X-ray photoelectron spectroscopy (XPS) gives insight into what proton irradiation changes at the surface of the oxides. All measurements show that ITO is less influenced than AZO. The proton energy and fluence used in this study simulate about a hundred years in low Earth orbit. This research demonstrates that both transparent conductive oxide thin films can function under simulated space conditions, with ITO showing superior resilience. The ITO film was more homogenous in terms of the total thickness measured with SE, had fewer defects and adsorbates present on the surface, as XPS analysis proved, and did not show a difference after irradiation regarding its optical properties, transmission, refractive index, or extinction coefficient. Full article

Tactile sensing is currently a research hotspot in the fields of intelligent perception and robotics. The method of converting external stimuli into electrical signals for sensing is a very effective strategy. Herein, we proposed a self-powered, flexible, transparent tactile sensor integrating sliding and proximity sensing (SFTTS). The principle of electrostatic induction and contact electrification is used to achieve tactile response when external objects approach and slide. Experiments show that the material type, speed, and pressure of the perceived object can cause the changes of the electrical signal. In addition, fluorinated ethylene propylene (FEP) is used as the contact electrification layer, and indium tin oxide (ITO) is used as the electrostatic induction electrode to achieve transparency and flexibility of the entire device. By utilizing the transparency characteristics of this sensor to integrate with optical cameras, it is possible to achieve integrated perception of tactile and visual senses. This has great advantages for applications in the field of intelligent perception and is expected to be integrated with different types of optical sensors in the future to achieve multimodal intelligent perception and sensing technology, which will contribute to the intelligence and integration of robot sensing. Full article

In this paper, we demonstrate a blazed phase grating to achieve tunable beam steering and propose a novel algorithm to reduce the stripe noise in wrapped phase. To control the diffraction angle to steer light to the desired direction, an electrically tunable transmission-type beam deflector based on liquid crystals is introduced, and electric fields are applied to the patterned indium tin oxide electrodes to change its phase retardation. Two different 2π phase-wrapping methods are applied to obtain various diffraction angles within the minimum cell-gap, and the method of equal interval of phase achieves a worthwhile diffraction efficiency compared to the methods based on equal interval of diffraction angle. The proposed method is able to completely eliminate the stripe noise in all steering angles that helps to improve the diffraction efficiency. Full article

The increasing demand for advanced transparent and flexible display technologies has led to significant research in thin-film transistors (TFTs) with high mobility, transparency, and mechanical robustness. In this study, we fabricated all-transparent TFTs (AT-TFTs) utilizing amorphous indium-zinc-tin-oxide (a-IZTO) as a dual-functional material for both the channel layer and transparent conductive electrodes (TCEs). The a-IZTO was deposited using radio-frequency magnetron sputtering, with its composition adjusted for both channel and electrode functionality. XRD analysis confirmed the amorphous nature of the a-IZTO layers, ensuring structural stability post-thermal annealing. The a-IZTO TCEs demonstrated high optical transparency (89.57% in the visible range) and excellent flexibility, maintaining a low sheet resistance with minimal degradation even after 100,000 bending cycles. The fabricated AT-TFTs exhibit superior field-effect mobility (30.12 cm²/V·s), an on/off current ratio exceeding 10⁸, and a subthreshold swing of 0.36 V/dec. The AT-TFT device demonstrated a minimum transmittance of 75.46% in the visible light range, confirming its suitability for next-generation flexible and transparent displays. Full article