Search Results (296)

Copper (Cu) thin films and meshes on polyethylene terephthalate (PET) substrates are promising flexible transparent conductive electrodes (TCEs), yet their practical use is limited by insufficient interfacial adhesion and poor oxidative stability on inert polymer substrates. This work addresses these issues via a synergistic strategy of interfacial layer engineering and maskless laser lithography-based aperiodic mesh patterning, systematically comparing ceramic (Al₂O₃) and metallic (NiCr) interfacial layers for PET-supported Cu films and fabricating Linear/Sinusoidal aperiodic Cu meshes with tailored performance. Magnetron sputtering shows that Ar plasma-activated NiCr interfacial layers form a gradient-alloyed interface with Cu via interdiffusion, achieving 5B-level adhesion, mitigating bending-induced stress concentration, and enhancing damp-heat resistance (85 °C/85% RH) by suppressing oxidation—outperforming brittle Al₂O₃ layers. Patterning the optimized Cu/NiCr/PET structure into micrometer-scale meshes yields a Linear design with superior optoelectronic performance (~10.8 Ω/sq sheet resistance, >87% transmittance at 550 nm) and a Sinusoidal design with enhanced bending robustness via stress delocalization. Microstructural and elemental analyses clarify the NiCr layer’s interfacial toughening and anti-oxidation mechanisms. Practical validation in flexible transparent heaters demonstrates rapid thermal response and >20 h continuous operational stability. This study provides a scalable design strategy for high-performance PET-supported Cu meshes, offering insights for interface and structural optimization of flexible metallic TCEs for next-generation optoelectronics. Full article

Silver nanowire (AgNW) networks have attracted significant attention as leading candidates for flexible transparent electrodes owing to their unique combination of high electrical conductivity, optical transparency, and mechanical compliance. This review presents an overview of recent developments in AgNW-based transparent electrode technologies, with particular emphasis on strategies to improve network conductivity and long-term reliability, including junction engineering, surface modification, encapsulation approaches, and composite structure design. Representative applications in flexible optoelectronic systems, such as organic light-emitting devices, transparent heating elements, and electrochromic platforms, are also discussed. Finally, current challenges and future research directions toward scalable manufacturing and practical implementation of high-performance AgNW electrodes are outlined. Full article

This review examines recent advances in multifunctional probes that integrate optical and electrochemical channels for in vitro/in vivo studies. Integration of electrodes with optical fibers provides a powerful platform for localized light delivery and simultaneous electrochemical detection of cellular metabolites both within and at the surface of single living cells. These hybrid devices bridge optical stimulation methods, including optogenetics, and electrochemical monitoring of the cellular response within the same experimental preparation. The review systematically categorizes distinct probe architectures: optical nanoendoscopes for intracellular measurements, probes with a shared opto-electrochemical channel, devices where optical and electrochemical channels are physically separated, and probes engineered for neural interfaces and scanning probe microscopy. For each category, fabrication approaches, surface modification strategies, and representative biological applications are discussed. Particular attention is given to the fundamental tension between optical transparency and electrical conductivity in shared-channel designs, to the mechanical requirements imposed by neural tissue on implantable probes, and to the spatial resolution limits of current scanning probe platforms. The review concludes with a critical assessment of current limitations and future directions, including higher spatial resolution, simultaneous multiplexed analyte detection and broader translation of these technologies toward in vivo experimental models. Full article

Stray-current corrosion from DC-electrified railways drives premature failure of buried metallic infrastructure (pipelines, foundations, tunnel reinforcement), causing resource waste, repair-driven carbon emissions and service disruptions that undermine the sustainability of urban transit corridors. Conventional impressed-current cathodic protection (ICCP) design relies on uniform-anode rules of thumb or closed commercial codes that cannot quantify the trade-off between protection uniformity, energy use and hardware cost. We present an open MATLAB framework that couples a custom 3D finite element method (FEM) solver with multi-objective particle swarm optimisation (MOPSO) and minimises three competing objectives simultaneously: total impressed current, RMS deviation from the protection target, and number of active anodes. A laboratory-calibrated coupling factor ($\mathrm{CF}=1.98$, consistent with the image-method prediction of 2 for a highly conductive pipe inclusion) absorbs the pipe–soil interface kinetics into a single direct FEM solve, and a pre-computed Green’s-function basis accelerates each MOPSO evaluation by more than two orders of magnitude. The solver is validated against an instrumented prototype with RMSE $=14.9$ mV across ten Cu/CuSO₄ saturated reference electrode (CSE) measurements, and applied to a 500 m DC traction line. At an identical total current of 20.30 A across five anodes, the optimised design achieves an RMSE of 86.6 mV against the $-850$ mV NACE target, whereas a conventional uniform layout produces severe over-protection (RMSE $=1107$ mV)—a twelve-fold reduction. The framework is recommended as a transparent, reproducible engineering tool that simultaneously extends pipeline service life and reduces rectifier energy demand, supporting UN Sustainable Development Goals 9 and 11 for sustainable urban-rail infrastructure. Full article

Multijunction solar cells employing a GaInP/GaAs/Ge triple-junction configuration are the dominant technology for space photovoltaic applications. The choice of an efficient electrode is crucial in solar cells, as it enables effective charge carrier collection and transport while allowing maximum light to reach the active layer. Indium tin oxide (ITO)/graphene hybrid electrodes have emerged as smart transparent conductors offering significant advantages over conventional brittle ITO films. Graphene electrodes were prepared by cold-wall chemical vapor deposition and ITO electrodes were commercially obtained and used as a base for hybrid ITO/graphene electrodes. Raman spectroscopy confirmed the successful integration and characteristic G and 2D bands on the ITO surface. Nanoscale current mapping via Tunneling Atomic Force Microscopy (TUNA-AFM) verified continuous conductive pathways throughout the film with ~60% increase in nanoscale tunneling current at graphene/ITO interfaces, indicating improved local charge transport pathways. These results demonstrate the suitability of ITO/graphene hybrid electrodes a promising material for multijunction solar cells and other aerospace technologies. Full article

Carbon nanotube (CNT) materials exhibit ultrahigh electrical and thermal conductivity. Upon electrical excitation, CNT-based transparent conductive films (TCFs) can emit far-infrared radiation (FIR) and provide certain physiotherapeutic efficacy, making them ideal candidates for thermotherapy applications. This work systematically tests and analyzes the fundamental physical properties and physiotherapeutic performance of CNT flexible thin-film heaters (TFHs) for potential use in health physiotherapy. Two types of TFHs with different electrode connection modes were fabricated via the prepared TCFs. Experimental characterizations were conducted on their response time, electrothermal performance, and heat transfer characteristics. The results showed that the temperature rise per unit input power for TFH1 was 16.71 °C/W, while that of TFH2 was 4.29 °C/W at the same voltage of 10 V. In addition, the variation trends of maximum temperature with power density were highly consistent for the two films. This demonstrates that TFHs fabricated using the same TCFs exhibit excellent and high electrothermal conversion efficiency as well as outstanding comprehensive electrothermal performance. In addition, smaller L/W ratio leads to lower resistance of TFHs, resulting in a stronger thermal effect under identical applied voltage. After the temperature stabilized, the surface temperature of the TFHs decreased by approximately 5 °C when attached to the human arm, confirming that the heat generated by the TFHs under electrical excitation could be effectively absorbed by the human body. The TFHs emitted rapid FIR upon electrification, and the peak wavelength ranged from 8 to 12 µm, which fell within the range of 6–14 µm that was easily absorbable by the human body. The heat can be rapidly absorbed by the skin and distributed throughout the body via blood circulation, yielding favorable physiotherapeutic efficacy. This study provides key physical parameters for the application of TFHs in wearable medical devices and physiotherapy equipment. Full article

Mine rescue operations are frequently conducted in hazardous underground environments characterized by damaged infrastructure, unstable communications, heat stress, and hypoxia risk, all of which threaten the safety of rescue personnel. To address these challenges, this study proposes a prototype-oriented mine-rescue monitoring framework that combines a Wi-Fi/optical-fiber communication architecture with flexible wearable sensing modules for physiological monitoring. The communication design employs Wi-Fi for local wireless data aggregation and optical fiber for reliable long-distance backhaul to the surface command side. For wearable monitoring, two flexible sensing modules were developed: a temperature sensor based on a polyaniline/graphene–polyvinyl butyral composite film and a PPG-oriented flexible optoelectronic module based on an ITO/Ag/ITO multilayer transparent electrode structure. Experimental results show that the temperature sensor exhibits a clear temperature-dependent resistance response within the tested range, while the optoelectronic module demonstrates low sheet resistance and acceptable electrical continuity under repeated bending. These results provide preliminary support for combining hybrid underground communication architecture with flexible wearable sensing components in mine-rescue scenarios. However, the present work remains at the stage of architecture design and component-level validation, and full end-to-end system verification under simulated or field rescue conditions will be the focus of future studies. Full article

Background: Surface electromyography (sEMG) of periocular muscles is a non-invasive technique used to assess eyelid dynamics and facial neuromuscular function, with applications in ophthalmology, neurology, and rehabilitation. Despite its clinical and research potential, substantial methodological variability—particularly in electrode placement, acquisition parameters, and signal processing—has limited reproducibility and hindered broader clinical translation. A comprehensive synthesis of existing methodologies was therefore needed to support future standardization. Objectives: The review aimed to systematically map current periocular sEMG methodologies, identify sources of methodological heterogeneity, organize findings into structured methodological domains, and develop a conceptual framework along with a minimum reporting set to promote transparency, reproducibility, and comparability across studies. Eligibility Criteria: Studies were eligible if they investigated surface electromyography of periocular muscles and reported methodological details related to electrode placement, signal acquisition, processing, or analysis. Randomized controlled trials, observational studies, and pilot investigations were included. No restrictions were placed on publication year. Sources of Evidence: Comprehensive searches were conducted in PubMed, Embase, and Web of Science from database inception through November 2025. Grey literature sources were also examined to enhance coverage and reduce publication bias. Charting Methods: Two reviewers independently screened records and extracted data. Extracted information was organized into predefined methodological domains. A thematic synthesis approach was used to identify recurring methodological patterns, and findings were integrated into a structured conceptual framework. Results: Sixteen studies published between 2002 and 2025 met the inclusion criteria, encompassing randomized trials, observational studies, and pilot investigations. Considerable heterogeneity was identified across studies in electrode characteristics, placement strategies, reference configurations, sampling frequencies, and normalization procedures. Three recurring methodological domains emerged: instrumentation and acquisition, analytical and normalization approaches, and clinical or experimental applications. Based on these domains, the authors developed a conceptual methodological framework and proposed a minimum reporting set intended to improve methodologyical transparency and support reproducibility and multicenter comparability. Conclusions: Periocular sEMG represents a promising yet methodologically fragmented field. This scoping review provides the first comprehensive synthesis of periocular sEMG practices and establishes an evidence-based platform for standardized acquisition, processing, and reporting. Adoption of the proposed framework may strengthen reproducibility, facilitate multicenter collaboration, and accelerate integration into clinical and research settings. Full article

Advanced solar energy-harvesting devices, such as optical rectennas, typically use metal–insulator–metal diodes because of the ultrafast response of these diodes at high frequencies. However, the diode performance is limited by weak current–voltage (I–V) asymmetry and optical losses in metallic electrodes. Graphene offers a promising alternative electrode material owing to its high carrier mobility, broadband optical transparency, and compatibility with nanoscale device architectures. Nevertheless, graphene-based optical rectennas face challenges associated with insufficient diode nonlinearity. In this study, we developed a vertically stacked graphene–double-insulator–graphene (GI²G) tunnel diode. Devices with various junction sizes were fabricated to investigate size-dependent rectifying behavior. A reduced graphene overlap area was defined by electron-beam lithography to introduce asymmetry and increase nonlinear conduction. An Al₂O₃/SiO₂ tunnel barrier composed of dielectrics with different band gaps and electron affinities improved the asymmetric I–V characteristics. Photoresponse measurements under AM1.5G illumination revealed a clear photocurrent, indicating rectification-related photoresponse. The photoresponse increased with decreasing junction area, which is consistent with enhanced rectification performance in smaller junctions. These results demonstrate that the GI²G tunnel diode provides a promising platform for next-generation energy harvesting and optical sensing applications. Full article

An ultrafast laser system combined with an optical delay line allowed ablation and in-scription at 1 kHz and 1 GHz pulse burst within transparent polyimide films. The two-photon-induced absorption results in clean surface ablation, while inscription results in polymer decomposition, creating carbonised regions within the polymer. Three pulse bursts at 1 GHz increased the observed coupling to the material significantly. Modified regions (with linewidths down to a few microns) were investigated using optical microscopy, white light interferometry, SEM and Raman spectroscopy, supporting the increasing carbon density relative to the pristine polymer. As depth of field was only a few microns at high NA, 3D micro-structuring was achieved. Polymer decomposition produces gaseous products, resulting in internal stress and thus affecting inscription fidelity. An inscribed subsurface electrode with dimensions of 5 mm × 0.3 mm × 3 μm connected to conducting vias had a resistance of R = 10.6 ± 0.2 kΩ, along with resistivity of ρ ~ 0.19 Ω cm; hence, it had DC conductivity, σ ~ 5.3 Scm⁻¹. This conductivity is similar to that of bulk graphite and could well form the basis of future flexible sensors, demonstrating single-step 3D subsurface inscription of carbon or laser-induced graphene structures. Full article

Transparent conductive oxides (TCOs), such as indium tin oxide (ITO), are essential for flexible electronics; however, conventional vacuum-based deposition is costly and thermally aggressive for polymers. This study investigated the surface functionalization of PET substrates with ITO thin film-based forced hydrolysis as a low-cost, reproducible alternative. $\mathrm{S}\mathrm{n}{\mathrm{O}}_2$ nanoparticles were synthesized by forced hydrolysis at 180 °C for 3 h and 6 h, yielding crystalline nanoparticles with a cassiterite phase and an average crystallite size of 20.34 nm. The process showed high reproducibility, enabling consistent structural properties without complex equipment or high-temperature treatments. The $\mathrm{S}\mathrm{n}{\mathrm{O}}_2$ sample obtained at 3 h was incorporated into commercial ${\mathrm{I}\mathrm{n}}_2{\mathrm{O}}_3$ to form a mixed In–Sn–O oxide, which was subsequently deposited onto PET substrates by spin coating onto UV-activated PET. The resulting 1.1 µm ITO films demonstrated good adhesion (4B according to ASTM D3359), a low resistivity of 1.27 × 10⁻⁶ Ω·m, and an average optical transmittance of 80% in the visible range. Although their resistivity is higher than vacuum-processed films, this route provides a superior balance of mechanical robustness, featuring a hardness of (H) of 3.8 GPa and an elastic modulus (E) of 110 GPa. These results highlight forced hydrolysis as a reproducible route for producing ITO/PET thin films. The thickness was strategically optimized to act as a structural buffer, preventing crack propagation during bending. Forced hydrolysis-driven PET sheet functionalization is an effective route for producing durable ITO/PET electrodes that are suitable for flexible sensors and solar cells. Full article

Transparent conductive films based on silver nanowire meshes have demonstrated significant potential as alternatives to conventional tin-doped indium oxide and fluorine-doped tin oxide thin films. However, these materials feature high junction resistance, poor damp heat (DH) stability, and weak mechanical adhesion to substrates, which are critical issues that must be addressed before any practical applications. In this paper, transparent conducting films composed of silver nanowire (AgNW) frameworks and amorphous indium zinc oxide (IZO) fillers were prepared by a spin-coating method. The AgNW-IZO composite films exhibited a higher conductivity and better DH stability and adhesion to substrates than that of their constituent parts alone. The lowest sheet resistance of the composite films was 3.3 ohm/sq with approximately 70% transparency in the visible spectrum. No degradation was observed after 8 months. The excellent DH stability and mechanical adhesion might facilitate applications of these AgNW-IZO composite films in optoelectronic devices. Furthermore, the composite electrode is shown to have potential as a transparent heater. Full article

The development of non-invasive sensors for individualised plant monitoring has become essential in smart farming to increase crop production. However current approaches are focused on the measurement of soil parameters instead, which cannot provide direct information about plant health. Moreover, equipment used for the direct monitoring of plant health are costly with complex operation, hindering their use by the wider community of farmers. This work reports for the first time the development of a flexible and highly transparent sensor, based on thin conductive PEDOT:PSS/PDMS hybrid films directly deposited onto leaves. The films were fabricated by aerosol deposition and could operate under two different modes. The first mode is used for the determination of plant dryness and concentration of ions. The second mode is used as a triboelectric generator to generate up to 7.2 µW cm⁻² electrical power through the friction of the sensors with a leaf. The device was assembled using a low-cost (GBP < 70) microcontroller incorporating environmental sensors, and an intuitive interface was designed for operation. The final sensor could determine the ionic strength at the millimolar level by means of the impedance of electrodes. This performance allowed the study of differences in ionic content and water availability in tomato leaves during day–night cycles. The high stability of the sensors also allowed the long-term monitoring of plant health. Using this technology, a decrease in the leaf ionic strength due to the lack of electrolytes was observed after watering with deionised water for 2 days. Upon supplementation with fertiliser, the recorded ionic strength and leaf water content were similar to the original values prior to the use of DI water, demonstrating the applicability of the device in the early detection of stress factors that could decrease crop production. Full article

Silver nanowire transparent conductive films (AgNW TCFs), as a promising new generation of transparent electrode materials poised to replace ITO, have long been plagued by inadequate optoelectronic performance. Herein, flash lamp sintering was used to facilitate rapid welding of TCFs, and the effects of process parameters and TCFs’ characteristics on the sintering outcomes were investigated. The leveraging of millisecond-scale intense light pulses of flash lamp sintering can achieve the rapid welding of AgNWs, thereby enhancing the optoelectronic performance of TCFs. The TCFs fabricated from 30 nm diameter AgNWs with an initial sheet resistance of 111 Ω/sq exhibited a reduced sheet resistance of 57 Ω/sq post-sintering, while maintaining a transmittance of 93.3%. The quality factor increased from 4.56 × 10⁻³ to 9.09 × 10⁻³ Ω⁻¹, and the surface roughness decreased from 6.12 to 5.19 nm after sintering. This work holds significant promise for advancing the continuous production of AgNW TCFs using flash lamp sintering technology, potentially paving the way for high-quality, low-cost, and rapid manufacturing of AgNW TCFs. Full article

Transparent conductive electrodes that combine flexibility with effective electromagnetic interference (EMI) shielding are important for next-gen flexible electronics and 5G/6G communication devices. Achieving high optical transparency, low sheet resistance, and broadband shielding performance remains a sophisticated task. This work demonstrates a solution: the synthesis and comprehensive characterization of flexible In₂O₃/Ag/In₂O₃ (IAI) structures on polyethylene terephthalate substrates. The optimized structure with a 13.2 ± 1.1 nm silver interlayer achieves an incredible combination of properties: high optical transmittance (82.59% at 500 nm), low sheet resistance (6.4 ± 0.8 Ω/sq), and insignificant optical haze (1.04%). Broadband EMI shielding measurements from 10 MHz to 1 THz reveal a uniform shielding effectiveness of 25–30 dB across band from radiowave to terahertz. The IAI structures also show outstanding mechanical resilience, maintaining their electrical and shielding performance under repeated bending. This unique set of attributes positions IAI thin films as a prospective material for transparent EMI shielding in advanced telecommunications and flexible optoelectronics. Full article