Conductivity Of Films Research Articles

Corrosion and conductivity damage of AgNW transparent conductive thin films under a simulated sulfur-containing atmosphere and mechanical force

Silver nanowire (AgNW) transparent conductive thin films possess high flexibility, high conductivity, high light transmittance and etc., demonstrating significant advantages in flexible electronics applications. However, in the service occasions, the coupled effect of corrosion and mechanical force easily makes the electrical conductivity of AgNW films deteriorate or even fail, which seriously affects the service reliability of AgNW films. In this work, scanning vibrating electrode technique was firstly used to confirm the existence of electrochemical corrosion on AgNW films. Furthermore, electrochemical measurements (including OCP, PDP and EIS) were carried out for researching the electrochemical corrosion process on AgNW films under different environmental factors and mechanical forces. Their surface morphologies and electrical conductivity were characterized and evaluated by the Scanning Electron Microscopy and square resistance tester respectively. Experimental results indicate that the corrosion-mechanics interaction effect aggravates the damage process of electrical conductivity of AgNW films.

A bio-based, self-healable, conductive rubber film with oxidized cellulose nanofiber segregated network

Rubber composites are indispensable in all areas of our daily lives. However, the formation of permanent crosslinked networks in rubber materials makes it difficult to recycle, resulting in a non-negligible waste of resources. In this paper, a vulcanization-free, fully bio-sourced rubber composite was prepared by using oxidized natural rubber (oNR) and oxidized cellulose nanofibers (TOCFs). TOCFs are selectively dispersed between the latex particles to form a segregated network. Meanwhile, the formation of hydrogen-bonding between oxygenated polar groups of oNR and abundant hydroxyl and carboxyl groups of TOCFs improves their interfacial interactions. This special structure promotes strain-induced crystallization (SIC) behavior of oNR matrix, giving its tensile strength up to 14.7 MPa. Furthermore, the oNR/TOCFs film shows excellent self-healing efficiency (96 %) at 40 °C for 5 h. The hygroscopicity of the TOCFs segregated network can turn the oNR/TOCFs film to be a conductive film by regulating the absorbed water content. The film has high conductivity (0.05 S/m) at a water content of 8.99 wt%, and the resistance change (RV/R0) can be varied between 1–5.9 × 10−6 at a water content range of 0–8.99 wt%, which makes it have potential for a wide range of humidity monitoring applications.

Synthesis of titanium-vanadium oxide thin films through thermal oxidation process for their use in CO gas sensing application

The thermal oxidation of evaporated titanium-vanadium thin films was carried out at different post-annealing temperatures. The structural, morphological, compositional, optical, electrical, and gas sensing properties of titanium-vanadium oxide thin films were primarily investigated. The results of the XRD study and Raman spectroscopy verified the presence of the orthorhombic V2O5, tetragonal TiO2, and monoclinic V2Ti3O9 phases. The crystallinity of TVO thin films was improved at higher annealing temperatures. The grain size (seen from SEM images) and oxygen compositions (obtained from EDS measurement) of TVO samples are also enhanced when the post-annealing temperature is increased from 500 to 575°C. From the transmittance curves, the bandgap values for TVO samples were estimated and found in the range of 2.14 to 2.36 eV. The n-type conductivity of TVO films was confirmed by the negative Hall coefficient values. At last, the CO gas sensing response of TVO thin films was analyzed by monitoring the change in the surface electrical resistances at different operating temperatures and CO gas concentrations. The dynamic and static resistances were assessed at different operating temperatures varying from 100 to 300°C. The TVO sample prepared at 550°C showed the best conditions by examining the materials and CO sensing properties.

Boosting thermoelectric performance of molecular junction by utilizing edge branches and weak coupling

In this study, we investigated the thermoelectric properties of molecular junctions, created by trapping naphthacene (C18H12) and rubrene (C42H28) molecules between two graphene electrodes. It is found that the charge transport of naphthacene-based and rubrene-based graphene junctions is not sensitive to the introduction of edge side branches or the increase in molecular length and still maintains resonance transport at the Fermi level. Notably, the presence of pendant branches on the molecular trunk in rubrene-based graphene junctions leads to a suppression of phonon transport, attributed to multiple scattering at the branch attachment points or Fano resonance scattering. The phonon thermal conductance of the rubrene junctions can be reduced by nearly half compared to that of naphthalene junctions. Furthermore, the room-temperature figure of merit (ZT) is significantly enhanced from 0.2 to 1.1 upon constructing weak coupling junctions, representing an almost tenfold increase over covalent junctions. These findings mean that it is highly desirable to find a mechanism that can suppress the phonon thermal conductance of self-assembled molecular films, while preserving their power factor at optimal levels to obtain high-efficiency thermoelectric performance.

Ultrahigh Electrical Conductivity in p-Type CsPbI2Br Perovskite Thin Films by Modulation Doping.

The widespread adoption of halide perovskites for application in thermoelectric devices, DC power generators, and lasers is hindered by their low charge carrier concentration. In particular, increasing their charge carrier concentration is considered the main challenge to serve as a promising room-temperature thermoelectric material. Efforts have been devoted to enhancing the charge carrier concentration by doping and composition engineering. However, the coupling between charge carrier concentration and mobility, along with the poor stability of these materials, impedes their development for thermoelectric applications. Herein, we demonstrate the successful increase in the charge carrier concentration of CsPbI2Br by forming a heterojunction structure with Cu2S via a facile spin-coating method. The excellent band alignment between two materials combined with a charge-transfer mechanism realizes the modulation doping, resulting in 8 orders of magnitude increase in carrier concentration from 1012 to 1020 cm-3 without detrimental effect on the carrier mobility of CsPbI2Br. The thermoelectric power factor of the heterostructured CsPbI2Br reached 6.6 μW/m·K2, which is 330 times higher than that of pristine CsPbI2Br. Furthermore, these films showed higher humidity stability than the control films. This study offers a promising avenue for increasing the charge carrier concentration of halide perovskites, thereby enhancing their potential for various applications.

Tailoring optical and electrical properties of PVP-I2 complexes through gamma irradiation-induced structural defect Engineering for optoelectronic applications

This study investigates the complexation of iodine with polyvinylpyrrolidone (PVP) subjected to gamma irradiation at doses of 0, 10, 20, and 30 kGy. The complex formation involves I2 acting as a Lewis acid with electron-rich PVP as a Lewis base through a charge transfer mechanism. UV–visible spectroscopy revealed a red shift of the absorption peak at 337 nm for irradiated PVP-I2 samples, indicating stronger interactions between the triiodide ion (I3¯) and irradiated PVP. FTIR analysis confirmed the formation of new C≡N moieties arising from PVP-I2 complexation. The FT-Raman analysis revealed a new C≡N peak at 2360 cm−1 in irradiated PVP-I2 samples, with increasing intensity correlating to higher irradiation doses, indicating enhanced electron delocalization due to complex formation. XRD analysis showed that PVP-I2 samples irradiated at 0 and 10 kGy exhibited higher crystallinity than those irradiated at 20 and 30 kGy, suggesting that high-dose irradiation causes PVP radiolysis and ring opening. Dielectric measurements demonstrated enhanced polarizability and ionic conductivity of irradiated PVP-I2 films, related to structural disorder promoting charge dissociation and ion mobility. The direct bandgap decreased from 2.75 eV for unirradiated samples to 2.55 eV for samples irradiated at 30 kGy, indicating the creation of new optically active defect states. Urbach energy increased from 0.85 eV to 1.55 eV with increasing irradiation dose, confirming increased disorder in the PVP structure. These findings reveal that gamma irradiation significantly alters the optical and electrical properties of PVP-I2 films by creating defects and disrupting structure, offering new insights for tailoring these materials for optoelectronic applications.

Boosting Through-Plane Electrical Conductivity: Chitosan Composite Films with Carbon-Sepiolite and Multiwalled Carbon Nanotubes

Flexible and electrically conductive materials are gaining significant attention across various domains, notably in electronics, biomedicine and food industry. One promising strategy involves the integration of electrically conductive nanostructures into a polymeric matrix to fabricate composite materials. However, achieving uniform through-plane electrical conductivity remains a challenge due to the preferential alignment of carbon nanostructures in the in-plane direction. Herein, we report the development of electrically conductive chitosan (CS)-based biocomposite films incorporating a multicomponent filler system. By combining carbon supported on sepiolite clay (CARSEP) with multiwalled carbon nanotubes (MWCNT), it is aimed to facilitate an interconnected distribution in both in-plane and through-plane directions. The optimized film, featuring a CS/CARSEP/MWCNT mass ratio of 50/40/10, exhibited a maximum electrical conductivity of 55.5 S/m and 0.1 S/m in the in-plane and through-plane directions, respectively. Additionally, migration studies demonstrated the absence of harmful compounds upon heating the film up to 60 °C in air, ethanol, or hexane. These findings highlight the potential of these flexible and electrically conductive biocomposite films, primarily composed of biobased materials, for applications requiring through-plane electrical conductivity.

Study on failure behavior of conductive and corrosion-resistant conversion film on magnesium alloy in damp-heat environment

Study on failure behavior of conductive and corrosion-resistant conversion film on magnesium alloy in damp-heat environment

The high transmittance silver nanowire conductive films with excellent electromagnetic shielding efficiency prepared by electrospinning and magnetron sputtering

The high transmittance silver nanowire conductive films with excellent electromagnetic shielding efficiency prepared by electrospinning and magnetron sputtering

High protonic resistance of hydrocarbon-based cathodes in PEM fuel cells under low humidity conditions: Origin, implication, and mitigation

Hydrocarbon-based electrodes for proton-exchange membrane fuel cells face challenges in closing the performance gap with electrodes based on perfluorosulfonic acid ionomers, particularly under low humidity conditions. Alongside increased oxygen transport resistance and higher kinetic-induced overpotentials, the protonic resistance of these fluorine-free electrodes is the primary hurdle to improved performance. This study systematically investigates the origin and impact of the cathode protonic resistance on fuel cell performance, utilizing sulfonated phenylated polyphenylenes as hydrocarbon ionomers. Electrochemical characterization at low relative humidity (≤50 %) reveal a high protonic resistance arising from both lower conductivity of the hydrocarbon thin film compared to the bulk membrane and increased cathode tortuosity at a gas transport-optimized ionomer to carbon (I/C) ratio of 0.2. The poor protonic resistance at low relative humidities leads to a non-homogeneous current distribution across the thickness of the cathode electrode, resulting in lower catalyst utilization. To address this issue, reducing the thickness of the cathode CL while maintaining a constant Pt loading (i.e., increasing the Pt on carbon ratio) significantly reduces protonic resistance. This improvement compensates for the kinetic disadvantages of highly loaded carbon particles and results in a considerable performance increase by 40 % at 0.75 V under low relative humidities.

Construction of Solution Processable NUS-8/PANI Nanosheets via Template-Directed Polymerization for Ultratrace Gas Sensing.

The advancement of wireless gas sensing signifies a substantial leap forward in gas detection and intelligent monitoring technologies. This necessitates stringent design criteria for gas sensitive materials with good solution processability, conductivity, and porosity, whose design and synthesis remain challenging yet highly sought-after. Herein, the fabrication of NUS-8/polyaniline (PANI) nanosheets is presented with excellent solution processability, high porosity, triboelectric property, and superior electrical conductivity via a template-directed polymerization strategy. Solution processable NUS-8 nanosheets, synthesized directly by a "one-pot" approach, serve as templates to enhance the "on-site" polymerization of aniline, resulting in the formation of PANI layer on NUS-8 nanosheets with a thickness of 7nm. The resultant NUS-8/PANI nanosheets exhibit outstanding solution processability, and a film conductivity of 8.6 Sm-1. The solution processability enables the facile fabrication of homogeneous and compact NUS-8/PANI films and thus their integration onto electronic devices targeted for multifunctional sensing. The NUS-8/PANI coated sensors demonstrate sensitive and selective detection at room temperature toward ultratrace ammonia with a detection limit of 120 ppb. A wireless sensing system based on the NUS-8/PANI-coated sensor is capable to monitor the spoilage process of meat. This study paves novel avenues for designing and synthesizing gas-sensitive materials for practical applications.

Characterization method of conductive film state of micro-cathode arc thrusters

Micro-Cathode Arc Thruster (μCAT) is an advanced electric propulsion system developed in the past decades to meet the maneuvering requirements of space microsatellites. However, the constraint on the its application is the short lifespan of the thruster. This is attributed to the conductive film, a key component of thruster discharge. In this study, we propose a measurement method for μCAT conductive film, and enables the evaluation of the evolution process of film thickness. The method is based on the four-probe resistivity testing theory and size effect fitting model, and establishes a method for characterizing the thickness and resistivity of μCAT conductive films. A comparison was made between the corrected resistivity test results of 1, 2, 5, and 10 μm film and the fitting results of the titanium film, revealing an error ofapproximately 10%. Additionally, a total of 2500 ignition experiments were conducted to verify the film thickness and resistance measurement of this method. This research serves as a valuable basis for the lifetime investigation of μCAT. Consequently, the thickness of the film progressively decreases with each discharge cycle, and the resistivity exhibits a corresponding increase due to the size effect. This method could be used as an effective method for exploring the μCAT lifespan and performance.

Significant Changes in Electrical Resistance of Conductive Porous Silicon Films Produced from Thiol-Modified Silicon Nanoparticle Inks

Conductive porous Si films composed of Si nanoparticles were produced by depositing a thiol-modified Si nanoparticle ink and then sublimating the thiol-modification surface, leaving Si–S bonds on the surface. By exchanging atmospheric gas such as N2 and O2, these S-terminated porous Si films reversibly changed electrical resistances in a dynamic range of five orders of magnitude, indicating that the resistance change was due to O2 adsorption/desorption on the S-terminated surface.

Electron-Surface Scattering from First-Principles.

Electron-surface scattering is important for many transport phenomena and practical applications. Particularly, the downscaling of microelectronics demands higher electrical conductivity for interconnects, which are currently based on Cu, which suffers from strong surface scattering. However, much is still unclear, such as which surface orientation causes stronger scattering. Existing theories require phenomenological parameters whose values are unknown unless fitted to experimental data or based on assumptions, thereby limiting their accuracy and predictive power. Here we present an accurate, parameter-free approach that enables an accurate calculation of electronic transport with surface scattering. Then we apply it to study the conductivities of Cu films with different surface orientations. Contrary to the common belief that a more compact surface should have higher conductivity, we find that (111) is less conductive than (001). This can be explained by the symmetry of the electronic structure. Furthermore, we propose a phenomenological model that has a better fit to the first-principles results than the conventional one. Our work offers insights into electronic transport and enables accurate calculation, understanding, and prediction for a broad range of systems where surface scattering matters.

Terahertz conductivity mapping of thin films on smart textiles

Smart textiles that promise to become sensors and actuators for multiple applications are an active area of research. Conductive textiles formed by coating a fabric with a conductive film will play a key role in such applications. Here we present contactless mapping of the terahertz (THz) conductivity of thin conductive films deposited on textiles. These conductivity maps enable non-destructive assessment of the conductivity of such layers and therefore the identification and localization of non-uniformities in local conductivity. The THz measurements are quantitatively consistent with four-point probe measurements of the same areas.

In-plane structural and electronic anisotropy of nanoporous Pt films formed by oblique angle deposition

Nanoporous Pt films fabricated by oblique angle deposition hold potential as electrocatalysts in various energy-related fields owing to their high surface area, structural stability, and adequate conductivity. In this study, we investigated the morphology, porosity, and electrical conductivity of nanoporous Pt thin films and systematically studied their interrelationships. Specifically, we revealed an in-plane anisotropy in the electrical conductivity that correlates with the surface morphology of the film. This anisotropy was evident in the resistance measurements along the in-plane lateral and vertical directions, which aligned well with our simple model. The results emphasize the significance of film morphology in determining the film’s electrical properties. This study contributes to the understanding of the physical properties of Pt films fabricated via oblique angle deposition and offers valuable insights for designing nanoporous films for various applications.

Enhanced Oxidation‐Resistant and Conductivity in MXene Films with Seamless Heterostructure

AbstractMXene‐based films have garnered significant attention for their remarkable electrical and mechanical properties. Nevertheless, the practical application of MXene is impeded by its intrinsic instability caused by spontaneous oxidation. The traditional anti‐oxidative strategies frequently lead to a compromise in stability, electrical conductivity, and mechanical properties. In this study, a novel approach is proposed involving metal nano‐armoring, wherein a copper layer with nano thickness is deposited onto MXene film surfaces to establish a uniform and seamless heterogeneous interface (MXene@Cu). The precise tunability and uniformity of this heterostructure are consistently demonstrated through both theoretical calculations and experimental results. The MXene@Cu films exhibit exceptional electrical conductivity of 1.17 × 106 S m−1, electromagnetic interference shielding effectiveness of 77.1 dB, and tensile strength of 43.4 MPa. More importantly, this heterostructure significantly improves MXene's stability against oxidation. After exposure to air for 30 days, the resultant MXene@Cu films exhibit a remarkable conductivity retention of 72.0%, significantly exceeding that of pristine MXene films (44.3%). This scalable synthesis approach holds significant promise for electronic device applications, particularly in electromagnetic shielding and thermal management.

Effect of Superfilling and Leveling Inhibitors in Hybrid Additives on the Microstructure Evolution of Electroplated Copper Interconnect Films during Self-Annealing

Abstract As the feature size shrinks, the main challenge for copper interconnect electroplating is to minimize interconnect resistance while ensuring the void-free feature filling, which is realized by the interaction of additives during electroplating. Among additives, hybrids are considered suitable for damascene filling because they combine type-I (superfilling) and type-II (leveling) inhibitors. However, it is generally believed that the more inhibitory an additive is, the more impurities it introduces into the films, thereby hindering grain growth during self-annealing, which paradoxically limits the conductivity of copper interconnects. To balance the inhibition of hybrid additives with their ability to introduce impurities, the effect of hybrid additives on the microstructure evolution of the films during self-annealing is explored in terms of texture, grain size, and impurity density, which are considered to determine the conductivity of copper films. We find that the {111} texture increases as the percentage of type-I inhibitors increases, whose relative texture coefficient reaches 97% after self-annealing due to the adsorption of hybrid additives on non-<111>-oriented crystal planes. Additionally, the impurity content and grain size increase as type-I inhibition increases, and so does the film conductivity after self-annealing, due to the possible promotion from impurities to the grain growth.

Thin Conducting Films: Preparation Methods, Optical and Electrical Properties, and Emerging Trends, Challenges, and Opportunities.

Thin conducting films are distinct from bulk materials and have become prevalent over the past decades as they possess unique physical, electrical, optical, and mechanical characteristics. Comprehending these essential properties for developing novel materials with tailored features for various applications is very important. Research on these conductive thin films provides us insights into the fundamental principles, behavior at different dimensions, interface phenomena, etc. This study comprehensively analyzes the intricacies of numerous commonly used thin conducting films, covering from the fundamentals to their advanced preparation methods. Moreover, the article discusses the impact of different parameters on those thin conducting films' electronic and optical properties. Finally, the recent future trends along with challenges are also highlighted to address the direction the field is heading towards. It is imperative to review the study to gain insight into the future development and advancing materials science, thus extending innovation and addressing vital challenges in diverse technological domains.

Enhancing electrical conductivity of RuO2 nanosheet-coated films by enlarging the nanosheet area

This study focused on enhancing the electrical conductivity of metal oxide nanosheet films by increasing the size of the nanosheets to promote the electron flow in the desired in-plane direction. We developed a method for increasing the size of RuO2 metal oxide nanosheets, a 2D material, by controlling the heat-treatment process. The size of the RuO2 nanosheets increased from 0.7 to 3.5 μm by modifying the heat-treatment conditions of KxRuO2, which was used as the precursor material. As a consequence, the electrical conductivity of the large-sized-RuO2 nanosheet-coated films was eight times higher than that of their small-sized counterparts. This lower resistance was attributed to the minimal number of contacts required for electron flow; the contact resistance between the nanosheets being higher than the intrinsic resistance. The proposed approach for enhancing the conductivity of metal oxide 2D materials is very promising and is expected to significantly contribute to the development of advanced flexible electronic devices.