Modern Electronic Industry Research Articles

Tunable Electromagnetic Interference Shielding Ability in a One-Dimensional Bagasse Fiber/Polyaniline Heterostructure

Development of highly efficient electromagnetic interference (EMI) shielding materials with tunable properties is essential for the modern electronics industry against severe electromagnetic pollut...

Facile Preparation of Highly Conductive Poly(amide-imide) Composite Films beyond 1000 S m-1 through Ternary Blend Strategy.

Highly conductive thin films with suitable mechanical performances play a significant role in modern electronic industry. Herein, a series of ternary conductive polymer composites were fabricated by incorporating carbon black (CB) into binary conductive polymer composites of poly(amide-imide) (PAI) and polyaniline (PANI) to enhance their mechanical and conductive properties simultaneously. By varying the composition of PAI/PANI/CB ternary films, the conductivity enhanced by two orders of magnitude compared with the sum of PAI/PANI and PAI/CB binary conductive polymer composites, and a high conductivity of 1160 S m−1 was achieved. The improved conductivity is mainly because much more continuous conductive networks were constructed in the ternary conductive polymer composites. With the help of the unusual morphology, the tensile strength was also enhanced by more than 80% from 21 to 38 MPa. The origin for the improved morphology was discussed for further improvement.

Significantly Enhanced Energy Density by Tailoring the Interface in Hierarchically Structured TiO2–BaTiO3–TiO2 Nanofillers in PVDF-Based Thin-Film Polymer Nanocomposites

Dielectric polymer nanocomposites with a high breakdown field and high dielectric constant have drawn significant attention in modern electrical and electronic industries due to their potential applications in dielectric and energy storage systems. The interfaces of the nanomaterials play a significant role in improving the dielectric performance of polymer nanocomposites. In this work, polydopamine (dopa)-functionalized TiO2-BaTiO3-TiO2 (TiO2-BT-TiO2@dopa) core@double-shell nanoparticles have been developed as novel nanofillers for high-energy-density capacitor applications. The hierarchically designed nanofillers help in tailoring the interfaces surrounding the polymer matrix as well as act as individual capacitors in which the core and outer TiO2 shell function as a capacitor plate because of their high electrical conductivity while the middle BT layer functions as a dielectric medium due to high dielectric constant. Detailed electrical characterizations have revealed that TiO2-BT-TiO2@dopa/poly(vinylidene fluoride) (PVDF) possesses a higher relative dielectric permittivity (εr), breakdown strength ( Eb), and energy density as compared to those of PVDF, TiO2/PVDF, TiO2@dopa/PVDF, and TiO2-BT@dopa/PVDF polymer nanocomposites. The εr and energy density of TiO2-BT-TiO2@dopa/PVDF were 12.6 at 1 kHz and 4.4 J cm-3 at 3128 kV cm-1, respectively, which were comparatively much higher than those of commercially available biaxially oriented polypropylene having εr of 2.2 and the energy density of 1.2 J cm-3 at a much higher electric field of 6400 kV cm-1. It is expected that these results will further open new avenues for the design of novel architecture for high-performance polymer nanocomposite-based capacitors having core@multishell nanofillers with tailored interfaces.

Flexible heat-treated PAN nanofiber/MoO2/MoS2 composites as high performance supercapacitor electrodes

We have synthesized heat-treated PAN/MoO2/MoS2 (PMOS) ternary structure nanofibers by facile solvothermal approach and in-situ conversion reaction. At discharge current density of 1 A/g, the synthesized hierarchical flexible fibers exhibit high specific capacitance of 439.8 F/g. A lightweight and small asymmetric supercapacitor device based on heat-treated PMOS nanofibers//active carbon (AC) delivers a ultrahigh energy density of 46 Wh/kg at power density of 2246.9 W/kg, and long-term capacity retention of about 98.9% after 2000 cycles. Remarkably, the solid-state asymmetric supercapacitor device could light up a LED belt, and no significant change in the brightness and duration when the device bends into a ring, indicating that the material has perfect flexibility and stability. These encouraging findings indicate that the heat-treated PMOS composite electrodes may have a promising potential application for advanced energy storage devices in modern electronic industries.

Engineered thiol anchored Au-BaTiO3/PVDF polymer nanocomposite as efficient dielectric for electronic applications

In modern electronic and electric appliances industries, polymer nanocomposites-based capacitors comprising of high dielectric constant ceramics (eg. BaTiO3 (BT), SrTiO3, CaCu3Ti4O12, etc.) and polymers (eg. polyvinylidene fluoride (PVDF), polyethylene terephthalate (PET), polycarbonate (PC), etc.) are becoming attractive for electrical energy storage applications. High dielectric constant fillers improve the energy density of the capacitors but at the cost of decreased efficiency, large dielectric loss as well as electrical conduction at high fields. In this paper, we present a novel dielectric core-satellite BT-gold (Au) nanoparticles (NPs) for high energy density capacitor application. Hydroxylated BT NPs (BTO NPs) were immobilized with Au NPs of size ∼4 nm and were used as fillers into PVDF polymer matrix. The results show that the incorporation of Au on BT NPs improved the dielectric constant, energy density as well as efficiency, while reduction in the dielectric loss. To further improve the dielectric properties, Au-BTO NPs were coated with 2,3,4,5,6-Pentafluorothiophenol (PFTP) layer. The dielectric properties were further tuned with different PFTP concentrations. The PFTP serves as the bridge between NPs and PVDF polymer by forming hydrogen bonding. The dielectric properties were measured at two different PFTP concentrations (PFTP1 and PFTP1.5, where 1 and 1.5 refer to the molar ratios of PFTP and Au decorated BT NPs). The lower PFTP concentration results in improved dielectric properties while increasing the concentration decreases the overall performance of the capacitors. The energy density of PFTP1-Au-BTO/PVDF was 2.04 J cm−3 at ∼2100 kV cm−1 which was ∼21% higher than that of PVDF and 70% higher than biaxially oriented polypropylene (BOPP), a present state-of-the-art dielectric polymer. Thus, the combination of both, Au decoration on BT NPs and hydrogen bonding of PFTP with PVDF chains are responsible for improved dielectric properties and make these nanocomposites a promising candidate for energy storage applications.

Preparation of Thermally Conductive Polymer Composites with Good Electromagnetic Interference Shielding Efficiency Based on Natural Wood-Derived Carbon Scaffolds

In the modern electronic industry, multifunctional polymer composites associated with heat removal and electromagnetic shielding are highly needed. This work reports a method to fabricate epoxy composites with high electromagnetic interference shielding effectiveness (EMI SE) and thermal conductivity (TC) using natural wood as a starting material via backfilling epoxy into wood-derived carbon scaffolds. The results showed that after carbonization at 1200 °C, the carbon scaffolds could be well-maintained, which could serve as thermally and electrically conductive pathways in the composites. The resultant composites at the carbon loading of 7.0 vol % possessed a high TC of 0.58 W/(m·K), an electrical conductivity of about 12.5 S/m, and an average EMI SE of 27.8 dB over the X-band at the thickness of only 2 mm. Our work proposed a promising strategy to use cost-effective and green materials to fabricate multifunctional polymer composites.

Evaluation of mechanical properties for TIG welding aspects of SS 310 and MS materials

Abstract Tungsten inert gas welding (TIG) is being extensively used as a crucial process in the modern automotive, aerospace, manufacturing and electronic industries as it can produce high quality welds with an appreciable accuracy. Quality of the weld and joint efficiency is the most obligatory requirement. Present work focused on evaluating the mechanical properties for TIG welding aspects of SS 310 and MS materials. An attempt has been made to investigate the influence of various parameters namely welding current, diameter of filler rod and gas flow rate on the responses such as tensile strength, percentage elongation and Rockwell hardness. Welding is performed to join 1.5 mm thick SS 310 and MS plates which were then made to ASTM standard tensile specimens to carry out the tensile test. The mechanical strength is also evaluated using Rockwell hardness test. The results revealed that it has a maximum tensile strength of 424.312 Mpa welded with 60 Amps and having a gas flow rate of 6 Lit/min by employing a filler rod of diameter 2 mm. Moreover, the maximum hardness value of 61 HRB was reported with the sample welded with 40 Amps & 5 Lit/min of gas flow rate by using a 1.5 mm diameter filler rod.

Fabrication of Morphologically Controlled Composites with High Thermal Conductivity and Dielectric Performance from Aluminum Nanoflake and Recycled Plastic Package.

Polymer composites with high thermal conductivity are highly desirable for modern electronic and electrical industry because of their wide range of applications. However, conventional polymer composites with high thermal conductivity usually suffer from the deterioration of electrical insulation and high dielectric loss, whereas polymer composite materials with excellent electrical insulation and dielectric properties usually possess low thermal conductivity. In this study, combining surface-oxidized aluminum (Al) nanoflake and multilayer plastic package waste (MPW) by powder mixing technique, we report a novel strategy for polymer composites with high thermal conduction, high electrical insulation, and low dielectric loss. The resultant MPW/Al, MPW/Al400, and MPW/Al500 composites exhibited the maximum thermal conductivity of 4.8, 3.5, and 1.4 W/mK, respectively, which exceeds those of most of the corresponding composites reported previously. In addition, all the composites still have high insulation (<10-13 S/cm) and maintain dielectric loss at a relatively low level (<0.025). Such a result is ascribed to the formation of an insulating Al2O3 shell and the continuous three-dimensional filler network, which is revealed by Agari model fitting coefficient. The model of effective medium theory qualitatively demonstrates that the lower interfacial thermal resistances of the MPW/Al composite can also benefit the high thermal conduction. This interfacial engineering strategy provides an effectively method for the fabrication of polymer materials with high-performance thermal management.

Tensilely Strained Ge Films on Si Substrates Created by Physical Vapor Deposition of Solid Sources

The development of Si-compatible active photonic devices is a high priority in computer and modern electronics industry. Ge is compatible with Si and is a promising light emission material. Nearly all Ge-on-Si materials reported so far were grown using toxic precursor gases. Here we demonstrate the creation of Ge films on Si substrates through physical vapor deposition of toxin-free solid Ge sources. Structural characterization indicates that a high tensile strain is introduced in the Ge film during the deposition process. We attribute the presence of such a tensile strain to the difference in thermal expansion coefficient between Si and Ge. A Ge peak, centered at ~2100 nm, is evident in the photoluminescence spectra of these materials, which might result from direct band gap photoluminescence alone, or from superposition of direct band gap and indirect band gap photoluminescence. These Ge-on-Si materials are therefore promising in light emission applications.

Flexible Li-doped ZnO piezotronic transistor array for in-plane strain mapping

Thin film is a good choice for in-plane strain sensing and is also technical compatible with modern electronic industry. In this paper, a thin film based piezotronic transistors array was demonstrated for the first time. The piezotronic effect of the sensing units was investigated and qualitative characterized. The strain sensitivity (gauge factor) of the units was derived up to 199, which is around 100 times of the sensitivity of the commercial foil gauge. After calibration on every sensing unit, the distribution of the strain applied on the device was successfully measured and mapped by the sensor array, which show the big potential of the thin film based piezotronic transistors array on the application of high space resolution, high sensitivity field deformation sensing.

Three-dimensional graphene network supported by poly phenylene sulfide with negative permittivity at radio-frequency

Percolative composites with negative permittivity can be promising candidates for metamaterials, but there is still a need about efficient method to adjust the permittivity value. Here graphene/poly phenylene sulfide composites were prepared and the dielectric property was studied. By gradually increasing the graphene content, three-dimensional conductive network could be constructed, accompanied by a change in the conductive mechanism from hopping conduction to metal-like conduction. Negative permittivity was achieved, and the Drude model indicated that negative permittivity came from the plasma oscillation in graphene network. The equivalent circuit analysis demonstrated that interconnection of graphene was the most crucial factor to adjust the negative permittivity value. That is, negative permittivity value can be effectively adjusted by graphene content. These findings may pave a way to simply and efficiently control negative permittivity and imply promising applications in modern electrical and electronic industries.

High dielectric permittivity and low loss of polyvinylidene fluoride filled with carbon additives: Expanded graphite versus reduced graphene oxide

Polymer dielectric composites with high dielectric permittivity and low dielectric loss play an increasing important role for modern electronic and electric industry. In this study, polyvinylidene fluoride (PVDF) incorporated with expanded graphite (EG) or reduced graphene oxide (rGO) was prepared by solution casting and the following hot pressing. The structure, morphology, and properties of the obtained products were characterized. In comparison with EG, rGO exhibits well dispersion and strong interaction with PVDF matrix. With the increasing content of conductive fillers, the dielectric permittivity of both PVDF/EG and PVDF/rGO composites shows an increasing trend whereas the dielectric loss keeps at a low level. The dielectric permittivity of PVDF filled with 4 wt% EG and 8 wt% rGO reaches 420 and 38 at 100 Hz, respectively. Moreover, the introduction of EG and rGO improves the mechanical strength and the thermal stability of PVDF matrix.

Semi-transparent biomass-derived macroscopic carbon grids for efficient and tunable electromagnetic shielding

High-performance electromagnetic interference (EMI) shields are urgently needed due to the rapid development of modern electronics industry. Herein, biomass-derived highly conductive macroscopic carbon grids (MCGs) were fabricated through the carbonization of wood-pulp fabric matting. The resultant MCGs with thickness of ∼0.3 mm exhibited not only exceptional EMI shielding effectiveness (SE) of ∼20.3–45.5 dB positively related with their carbonization temperature or negatively associated with their empty grid size, but also semi-transparent characteristic with the transparency of ∼15%–56% originated from their grid-like configurations. Moreover, an accurate EM model was constructed for the SE simulation of the MCGs in the 3-D full-wave simulation. Furthermore, it is demonstrated that the EMI SE of double-layered MCG sample could be conveniently tuned by changing the interleaving degree of the stacked grids through tiny translational motion under constant thickness, showing potential for the design of EM attenuating devices with tunable performance.

Precision structuring and functionalization of ceramics with ultra-short laser pulses

High-performance ceramics have been firmly established for the manufacturing of tools and components in the modern electronics industry and mechatronics. Various components such as circuit boards, bearings, and sensors benefit from their specific characteristics, such as wear resistance, stiffness, and electrical neutrality. Apart from these advantages, the brittleness and hardness of ceramics turn the mechanical processing into a challenging and difficult task. Against this background, modern laser technologies have already been used to process ceramics for many years, enabling a contactless and wear-free machining. However, regarding high precision applications, for instance, the drilling of micro-holes or the fabrication of well-defined cavities and three-dimensional structures, conventional laser processes reach their limits. Especially due to thermal influences of the laser radiation, brittle edges, stresses, and redeposited layers emerge. Ultrashort pulse lasers enable completely new processing qualities in these fields. The extremely short pulse durations within the pico- and femtosecond range lead to nonlinear absorption mechanisms and an almost athermal material removal. Thereby, dielectric materials can be processed precisely and gently. In the course of a comprehensive process study, the beam–material interactions of ultrashort pulses with ceramics have been investigated. Besides the material properties, the ablation process is influenced by a multitude of laser parameters, such as wavelength, pulse overlap, and fluence. In order to reveal the most important variables, the experiments have been conducted by applying modern statistical methods. Using alumina (Al2O3) as an example, it is shown how different parameter regimes lead to disparate process qualities and efficiencies. The generated models have been used to optimize industrially interesting applications, from the separation of ceramic printed circuit boards to the realization of precise design structures.

A Novel Coarse–Fine Method for Ball Grid Array Component Positioning and Defect Inspection

With high production efficiency and robustness, automatic component pick-and-place technology is widely used in modern electronic industries. As one of the core components of this technology, the visual measurement system requires a suitable positioning and fault detection algorithm with high speed, accuracy, robustness, and generalization abilities, especially for positioning and inspecting ball grid array (BGA) components. This paper examines the online positioning and defect inspection problem of BGA components for component placement machines. Incorporating coarse and fine positioning, an accurate, efficient, and robust universal positioning algorithm is proposed. Two types of key points are introduced to characterize the alignment of solder balls in BGA components. A distance transform-based circle detection method is first applied, and then a distance-based edge filter and a circle fitting method are employed to obtain the coarse and fine locations of solder balls, respectively. The approximate location of the component is estimated using a geometrical method and the fine location is calculated by solving a least-squares problem. A pair of overlapping ratios is introduced to conduct fault detection and inspect the alignment accuracy. The effectiveness of the proposed method is verified by applying it to several real component positioning and defect inspection experiments.

Microstructure, mechanical and thermo-physical properties of Al–50Si–xMg alloys

There is a growing demand to achieve better performance of electronic packaging materials owing to the development of modern electronics industry. In this work, the effects of elemental Mg addition on microstructural characteristics, mechanical properties, and thermo-physical properties of Al–50Si alloys were investigated. The tensile strength, bending strength, and hardness are improved significantly when the Mg content increases from 0% to 1%, but decreases as the content exceeds 1%. The enhanced strength is mainly attributed to the presence of small bar-like Mg2Si phase located at the interface. However, the extensive growth of Si phase in the high Mg contained alloys reduce the mechanical properties. The thermal conductivity and thermal expansion coefficient decrease gradually with the increase in the Mg content. Compared with the addition of Cu, minor amount of Mg addition (0.5%) can effectively increase the strength of Al–50Si alloys without substantially sacrificing the thermal conductivity.

Surface modification-based three-phase nanocomposites with low percolation threshold for optimized dielectric constant and loss

Integration of the excellent attributes of high dielectric constant and low dielectric loss in flexible polymer-based nanocomposites has attracted increased research attention because of their extensive applications in modern electronic and electric industry. In this study, to obtain the optimized dielectric constant and loss, the fabrication and properties of a three-phase nanocomposites, including poly(vinylidene fluoride) (PVDF) and two nanofillers, namely, surface-modified multi-wall carbon nanotubes (mCNTs) and barium titanate nanoparticles (mBTs), are investigated in detail. The mCNTs and mBTs were obtained via the hydrolysis of 3-aminopropyltriethoxysilane (AMEO) and condensation reactions between the AMEO and nanofillers. The three-phase nanocomposites are fabricated by a phase-separation and hot-pressing process. The mCNTs and mBTs can be uniformly dispersed within the PVDF polymer matrix because of the enhanced hydrogen bonding interaction and compatibility with the polymer matrix. The percolation threshold (as low as 0.50vol%) of the two-phase mCNTs/PVDF nanocomposites is adopted to optimize the dielectric properties of the three-phase mCNTs/mBTs/PVDF nanocomposites. At the frequency of 102Hz, a high dielectric constant of 109 and low loss of 0.06 are obtained for the three-phase nanocomposites with only 0.41vol% mCNTs and 2.8vol% mBTs, respectively. Meanwhile, owing to the low percolation threshold and enhanced surface compatibility between the nanofillers and PVDF, the tensile strength of the three-phase nanocomposites is greater than that of PVDF by a factor of greater than 1.5. Owing to their high dielectric constant, low dielectric loss and good mechanical properties, these PVDF-based ternary nanocomposites show potential for applications in electronic devices and energy storage systems.

Strait Gate: Special Issue on Advances in Silicon Chemistry

Manufacturing high-purity element silicon and organic polysilicones are two major silicon industries, supporting the basis of the modern electronic industry and our daily lives [...].

Synergistic influence from the hybridization of boron nitride and graphene oxide nanosheets on the thermal conductivity and mechanical properties of polymer nanocomposites

Enhancing the thermal conductivity of polymers by introducing inorganic fillers with low content remains challenge in modern electronic industries. By homogeneously incorporating both functionalised boron nitride nanosheets and graphene oxide nanosheets at low loading less than 1 wt%, a poly(vinyl alcohol) (PVA) polymer was able to reach in-plane thermal conductivity of 9.90 W/m·K as well as achieve high extensibility and toughness. Synergistic influences of both nanofillers were observed and the improved nanofiller/matrix interfaces and the nanofiller distribution were ascribed to the remarkable enhancement in thermal conductivity. The facile fabrication process has potential to be scaled-up that has significance in preparation of thermal conductive polymers and composites for heat dissipation.

Tuning Phase Composition of Polymer Nanocomposites toward High Energy Density and High Discharge Efficiency by Nonequilibrium Processing.

Polymer nanocomposite dielectrics with high energy density and low loss are major enablers for a number of applications in modern electronic and electrical industry. Conventional fabrication of nanocomposites by solution routes involves equilibrium process, which is slow and results in structural imperfections, hence high leakage current and compromised reliability of the nanocomposites. We propose and demonstrate that a nonequilibrium process, which synergistically integrates electrospinning, hot-pressing and thermal quenching, is capable of yielding nanocomposites of very high quality. In the nonequilibrium nanocomposites of poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) and BaTiO3 nanoparticles (BTO_nps), an ultrahigh Weibull modulus β of ∼30 is achieved, which is comparable to the quality of the bench-mark biaxially oriented polypropylene (BOPP) fabricated with melt-extrusion process by much more sophisticated and expensive industrial apparatus. Favorable phase composition and small crystalline size are also induced by the nonequilibrium process, which leads to concomitant enhancement of electric displacement and breakdown strength of the nanocomposite hence a high energy density of ∼21 J/cm3. Study on the polarization behavior and phase transformation at high electric field indicates that BTO_nps could facilitate the phase transformation from α- to β-polymorph at low electric field.