Conductivity Of Films Research Articles

Investigating the failure mechanism of wet eMachines in presence of transmission oils

Abstract This paper investigates the failure mechanisms in electric machines used in heavy trucks and buses exposed to transmission oil. Five machines from field operations were examined. Subsystem tests–copper corrosion testing, conductive deposit tests, material compatibility tests, and oil analysis–were conducted. Copper sulfide, known for its conductive properties, was found in failed machines and during subsystem tests with lubricants containing reactive sulfur components in contact with exposed copper. Two prerequisites for the chemical reaction–presence of reagents and sufficient activation energy–were met at normal operating temperatures. Analysis revealed sulfur presence in damaged machines and identified cracks in the polymer coating on copper wires, allowing corrosive substances to reach the copper surface. The proposed failure mechanism involves active sulfur reacting with copper to form copper sulfide. These layers can create contact bridges between phases in the eMachine, leading to short circuits, sharp temperature increases, electrical arcing and total machine failure. Coating aging experiments showed that fluids can form conductive films on the polymer layer. Oil conductivity measurements showed minor changes within the static dissipative regime, and contamination by transmission and axle oil elements was found in failed eMachines but not in functional ones. Activation energy experiments demonstrated that copper sulfide forms at normal operating temperatures, with damage likely within 10-100 days depending on conditions. These findings highlight the risks associated with certain oils in eMachines and the need for further research to develop strategies to mitigate these risks and ensure long-term reliability.

The Experimental Study on the Thermoelectric Properties of Sputtered Amorphous Molybdenum Disulfide Films

ABSTRACT Molybdenum disulfide (MoS2), a promising two-dimensional material, has attracted significant attention due to its unique electronic and thermal properties, making it a potential thermoelectric material Extensive research is underway to improve the thermoelectric properties of MoS2 by enhancing the figure of merit (ZT). However, there is currently limited research on the effects of thickness and temperature on the thermoelectric properties of MoS2 films prepared by magnetron sputtering. In this paper, amorphous MoS2 films with different thicknesses were first deposited using magnetron sputtering, ranging from 43nm to 231nm. The Frequency Domain Thermoreflectance (FDTR) system was established to measure the thermal conductivity of MoS2 film. The experimental results indicate a thermal conductivity range of 0.49 to 0.53W/m·K, with thickness showing minimal impact. The thermal boundary conductance between the sputter-deposited MoS2 film and the SiO2 substrate is measured at 12±5MW/m2 ·K. The electrical conductivity and Seebeck coefficient were measured in the temperature range of 300 K to 450 K using LSR-3 equipment. The results indicate that the MoS2 films prepared in this study were all p-type semiconductors, with electrical properties increasing with temperature. Within the temperature range of 300–430 K, the power factor of all films increases with the rise in temperature, reaching a maximum value of 0.36 µW/cm·K2

Research on the enhancement of densification and electrical conductivity of silver-coated copper conductive films via oxidation–reduction sintering method

Research on the enhancement of densification and electrical conductivity of silver-coated copper conductive films via oxidation–reduction sintering method

Layer-by-layer ultrathin conductive polymer film for optoelectronics: selenophene versus thiophene

Layer-by-layer ultrathin conductive polymer film for optoelectronics: selenophene versus thiophene

Thermally conductive graphene-based films for high heat flux dissipation

Thermally conductive graphene-based films for high heat flux dissipation

A sandwich-structured anisotropic conductive film with robust interfacial reliability and conductivity for functional electrical interconnections

A sandwich-structured anisotropic conductive film with robust interfacial reliability and conductivity for functional electrical interconnections

Optimizing electrical resistivity in flexible conductive films by way of silver nanowire doping

Silver nanowires (AgNWs) have attracted significant research interest due to their potential in conductive films, flexible electronics, electromagnetic interference shielding, sensors, energy storage, and integration into wearable devices. This study developed conductive inks with tailored viscosities for fabricating films with stable electrical resistance. The formulations were optimized for screen printing, inkjet printing, and direct writing by doping AgNWs into carbon paste dispersed in N,N-dimethylformamide. Flexible conductive circuits were printed on silk film substrates, and their electrical resistance was evaluated by varying AgNW concentration and the number of printed layers. Cyclic bending and energizing heating experiments were conducted to assess durability. The results demonstrated that doping with AgNWs significantly reduced film resistivity, with a concentration of 30 mg/ml being optimal for screen printing, inkjet, and direct printing. Screen-printed films exhibited the lowest resistivity, decreasing from 1.2 × 10−4 to 3.5 × 10−5 Ω·cm with increasing AgNWs concentration from 5 to 30 mg/ml. The resistivity of inkjet-printed and direct-written films at 30 mg/ml AgNWs was 5.8 × 10−5 and 7.2 × 10−5 Ω·cm, respectively. Increasing the number of printed layers from one to seven further reduced resistivity by 62% for screen printing, 58% for inkjet printing, and 55% for direct writing. Cyclic bending tests showed that after 1000 bending cycles, the resistance increased by 18% for screen-printed films, 25% for inkjet-printed films, and 30% for direct-written films. Screen-printed films exhibited the lowest resistivity and longest service life, highlighting their potential for diverse applications in flexible electronics and the broader electronics industry.

Heteroleptic "open ruthenocene" for deposition of Ru films from the gas phase.

A volatile heteroleptic open ruthenocene has been synthesised and characterised by NMR and single crystal X-ray diffraction. Using this compound as a precursor and oxygen as a co-reactant, a highly conductive Ru film has been deposited on Si with native oxide at 220 °C. Under the same deposition conditions, the film thickness obtained with the new compound has almost doubled compared to its homoleptic analogue.

Modelling the effect of deposited grid material on the power coupling of radio frequency ion thrusters

For radio-frequency(RF) ion thrusters, under nominal operating conditions, sputtering of the screen grid can lead to the formation of a conductive film of the grid material on the inner walls of the discharge chamber which leads to a decrease in RF coupling to the plasma. When the ion beam becomes unfocused, either due to off nominal operating conditions or as a result of lifetime degradation, this process can be accelerated. An RF ion thruster performance model is developed, which can quantitatively simulate the performance degradation caused by sputter deposition on the thruster. This model couples an RF power transmission model, a zero-dimensional thruster discharge chamber model, and a sputter deposition model. An experiment that intentionally enhances the erosion of the accelerator grid to accelerate the formation of the conductive film confirms the power transmission process described by the model. As a result, the deposition on the discharge chamber walls primarily originates from the sputtering of the accelerator grid by the ion beam. At a xenon flow rate of 0.63 sccm and RF power of 42 W, a 2.015 μm copper film deposited on the walls resulting in a decrease in thruster screen grid current. The simulated results indicate that the power absorbed by the plasma decreases after deposition, which is the primary cause of the screen grid current reduction. Using materials with low conductivity for the deposition layer in the construction of the accelerator grids can reduce the impact of the deposition layer on the thruster screen grid current.

MXene–MWCNT Conductive Network for Long-Lasting Wearable Strain Sensors with Gesture Recognition Capabilities

In this work, a conductive composite film composed of multi-walled carbon nanotubes (MWCNTs) and multi-layer Ti3C2Tx MXene nanosheets is used to construct a strain sensor on sandpaper Ecoflex substrate. The composite material forms a sophisticated conductive network with exceptional electrical conductivity, resulting in sensors with broad detection ranges and high sensitivities. The findings indicate that the strain sensing range of the Ecoflex/Ti3C2Tx/MWCNT strain sensor, when the mass ratio is set to 5:2, extends to 240%, with a gauge factor (GF) of 933 within the strain interval from 180% to 240%. The strain sensor has demonstrated its robustness by enduring more than 33,000 prolonged stretch-and-release cycles at 20% cyclic tensile strain. Moreover, a fast response time of 200 ms and detection limit of 0.05% are achieved. During application, the sensor effectively enables the detection of diverse physiological signals in the human body. More importantly, its application in a data glove that is coupled with machine learning and uses the Support Vector Machine (SVM) model trained on the collected gesture data results in an impressive recognition accuracy of 93.6%.

Reversible Ferroelectric Polarization Modulation of Chiral Molecular Ferroelectrics by Circularly Polarized Light.

The optical modulation of ferroelectric polarization constitutes a transformative, non-contact strategy for the precise manipulation of ferroelectric properties, heralding advancements in optically stimulated ferroelectric devices. Despite its potential, progress in this domain is constrained by material limitations and the intricate nature of the underlying mechanisms. Recent studies have achieved efficient regulation of ferroelectric polarization and thermal conductivity in chiral ferroelectric thin films through the application of left- and right-handed circularly polarized light (LCP and RCP). Differential absorption of circularly polarized light (CPL) induces nonequilibrium carrier dynamics, generating distinctive interfacial electrostatic fields that enable precise control of ultrathin ferroelectric films. For (R)-BINOL-DIPASi and (S)-BINOL-DIPASi (C26H26O2Si), polarization changes surpass 23%, exhibiting opposite response under LCP and RCP excitation. In R chiral films, remnant polarization decreases from 1.05 µCcm- 2 under LCP to 0.85 µCcm- 2 under RCP, whereas in S chiral films, polarization increases from 0.85 µCcm- 2 under LCP to 0.98 µCcm- 2 under RCP. This reversible modulation facilitates reliable switching between ON and OFF states, presenting the potential of chiral ferroelectric materials for flexible, high-speed integrated photonic sensor technologies.

Unveiling the Origin of the Scale-Dependent Conductivity of Ni3(HITP)2 Metal-Organic Framework Thin Films.

Conductive metal-organic frameworks (MOFs) are crystalline, intrinsically porous materials that combine remarkable electrical conductivity with exceptional structural and chemical versatility. This rare combination makes these materials highly suitable for a wide range of energy-related applications. However, the electrical conductivity in MOF-based devices is often limited by the presence of different types of structural disorder. Here, the electrical transport characteristics of high quality Ni3(HITP)2 nanometer-thin films are reported. These findings reveal a tenfold difference in conductivity between the micro- and nano-scale, attributed to poor electrical connection among a limited number of crystalline grains. Average in-plane conductivity values at the micro- (σIP,micro = 0.7 ± 0.3 Scm-1) and nano- (σIP,nano = 6 ± 3 Scm-1) scales is determined, and the value of the inter-grain resistance, Rinter-grain = 40 kΩ is found. Using a 2D resistor network model with a 40 kΩ base resistance and scattered higher resistances, surface potential maps of in-operando MOF-based electrical devices are successfully reproduced. Additionally, a structure-property relationship that links the density and spatial distribution of electrical failures in inter-grain connections to the observed micro-scale conductivity in MOF thin films is established.

Physical and electrical properties of silica

Nominally pure silica or amorphous SiO2 is an important material in modern electronics, as well as other fields of science. Normally, it has been utilized for its insulation properties, for example, in metal-oxide-semiconductor devices. However, it also can be considered as a wide bandgap semiconductor possessing very large electrical resistivity. The conductivity of various silica films has been studied since the mid-nineteenth century, usually assuming the presence of ionic conductivity. However, in the sense of a wide bandgap semiconductor, the temperature dependence of the resistivity, which ranges over more than four orders of magnitude, can be accurately explained by normal semiconductor behavior under the presumed presence of a deep electron trap/donor residing ∼2.3 eV below the conduction band edge. That is, the conductance is determined by electron motion and not by ions. Experiments have studied the transport of injected electrons (and holes) which are consistent with this viewpoint.

Preparation and Optoelectrical Property of Silver Nanowire Transparent Conductive Film via Slot Die Coating

Silver nanowire transparent conductive films (AgNW TCFs), as the novel transparent electrode materials replacing ITO, are anticipated to be applied in numerous optoelectronic devices, and slot-die coating is currently acknowledged as the most suitable method for the mass production of large-sized AgNW TCFs. In this study, sodium carboxymethyl cellulose (CMC) and polyvinyl alcohol (PVA), as film-forming aids, and AgNWs, as conductive materials, were utilized to prepare a specialized AgNW ink, and a slot-die coating is employed to print and prepare AgNW TCFs. The optoelectrical properties of AgNW TCFs are optimized by adjusting the compositions of AgNW ink and the process parameters of slot-die coating. The suitable compositions of AgNW ink and the optimal parameters of slot-die coating are a CMC type of V, a PVA volume of 1 mL, a AgNW volume of 1.5 mL, a volume ratio of 30 and 45 nm AgNWs (2:1), and a coating height of 400 μm. The resultant AgNW TCFs achieve excellent comprehensive optoelectronic performance, with a sheet resistance of less than 50 Ω/sq, a visible light transmittance exceeding 92%, and a haze below 1.8%. This research provides a valuable approach to producing AgNW TCFs on a large scale via the slot-die coating.

Influence of Proton Irradiation on Thin Films of AZO and ITO Transparent Conductive Oxides—Simulation of Space Environment

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.

Improving the performance of solar cells by optimizing the interface of SnO2/perovskite layer using sodium citrate

Interface engineering is an important means of modifying perovskite solar cells (PSCs). In this paper, a strategy for modifying the SnO2/perovskite interface transport layer using sodium citrate (SC), an organic sodium salt, was proposed. The optimal power conversion efficiency was 22.55%, 9.3% higher than that of devices without SC modification. The open circuit voltage (Voc) reaches a respectable 1.20 V. This method enhances the conductivity of thin SnO2 films with inert photocatalytic performance, improves the crystallinity of perovskite, and increases the grain size, thereby meliorating the performance and stability of PSCs.

Thermal conductivity of AlN thin films deposited by reactive DC magnetron sputtering on different substrates using ultra-fast transient hot strip technique

In the frame of this work, we report a profound insight into the thermal conductivity (k) of aluminum nitride (AlN) thin films deposited on AlN-molecular beam epitaxy (MBE)/Si(111) and AlN-Kyma/Si(111) substrates at low temperatures (<200 °C) using reactive direct current magnetron sputtering (DCMS). Our concern is not on the thermal properties at the nanoscale, but rather on relating thermal macroscopic properties to the microstructure for submicronic to micronic AlN films. As the mean free path for AlN material is about 100 nm, the thickness of our films lies between 400 nm and 2 μm. The k measurements were conducted using the ultra-fast transient hot strip technique. It was found that the k values of the deposited films change depending on both the substrate type and the film thickness. For the 500 nm AlN thick film, k value was about 250 W m−1 K−1 for AlN-DCMS films grown on 10 nm AlN-MBE/Si against 90 W m−1 K−1 for those deposited on 200 nm AlN-Kyma/Si. The thermal boundary resistance has been computed equal to (0.25 ± 0.08) × 10−9 K m2 W−1 on 10 nm AlN-MBE/Si against (3.56 ± 1.50) × 10−9 K m2 W−1 on 200 nm AlN-Kyma/Si. Additionally, both pole figures and high resolution transmission electron microscopy confirm k results. In fact, pole figures confirm the good crystal quality of the film on both substrates, but HR-TEM analyses show that the AlN films grown on 10 nm AlN-MBE/Si template exhibit good crystalline quality with an epitaxial regrowth and abrupt interface compared to those obtained for 200 nm AlN-Kyma/Si. It also appears that the thermal boundary resistance plays a major role in the thermal properties of AlN films.

Damp‐Heat–Induced Degradation of Lightweight Silicon Heterojunction Solar Modules With Different Transparent Conductive Oxide Layers

ABSTRACTLightweight photovoltaic applications are essential for diversifying the solar energy supply. This opens up vast new scenarios for solar modules and significantly boosts the capacity of renewable energy. To ensure high efficiency and stability of the solar modules, several challenges need to be overcome. Degradation due to elevated temperature and/or humidity is a critical concern for silicon heterojunction (SHJ) solar modules. Here, we investigated the stability and degradation mechanism of encapsulated cells with lightweight configurations where the cells are based on three different types of transparent‐conductive oxide (TCO): indium tin oxide (ITO), aluminum‐doped zinc oxide (AZO), and a combination of ITO/AZO/ITO under humid and thermal environmental conditions. A damp heat (DH) test at a temperature of 85°C and relative humidity (RH) of 85% was performed on lightweight modules for 1000 h. Our results show that AZO is the most susceptible to DH degradation. The AZO film was damaged by the combined effects of moisture ingress and delamination of the interconnection foil, resulting in a decrease in the conductivity of the AZO film, leading to a dramatic increase in Rs and a decrease in FF of the modules. Consequently, moisture has a greater chance of percolating through the damaged AZO layer into the a‐Si:H passivation layer, causing passivation degradation, which leads to an increase in recombination, resulting in a decrease in Voc of the modules. In particular, after capping the AZO film with an ITO film, the efficiency loss of the ITO/AZO/ITO module was significantly reduced. This suggests that the ITO film could be a promising protective capping layer for the AZO‐based solar cells.

Improvement in Conductivity and Mechanical Stability of a AgNW-Based Transparent Conductive Film by Using Ag Ionic Ink

Improvement in Conductivity and Mechanical Stability of a AgNW-Based Transparent Conductive Film by Using Ag Ionic Ink

Temperature‐Dependent Properties of Atomic Layer Deposition‐Grown TiO2 Thin Films

AbstractThis study investigates the presence of titanium oxynitride bonds in titanium dioxide (TiO2) thin films grown by atomic layer deposition (ALD) using tetrakis dimethyl amino titanium (TDMAT) and water at temperatures between 150 and 350 °C and its effect on the films’ optical and electrical properties. Compositional analysis using X‐ray photoelectron spectroscopy (XPS) reveals increased incorporation of oxynitride bonds as the process temperature increases. Furthermore, depth profile data demonstrates an increase in the abundance of this type of bonding from the surface to the bulk of the films. Ultraviolet‐visible spectroscopy (UV‐vis) measurements correlate increased visible light absorption for the films with elevated oxynitride incorporation. The optical constants (n, k) of the films show a pronounced dependence on the process temperature that is mirrored in the film conductivity. The detection of oxynitride bonding suggests a secondary reaction pathway in this well‐established ALD process chemistry, that may impact film properties. These findings indicate that the choice of process chemistry and conditions can be used to optimize film properties for optoelectronic applications.