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Currently, sophisticated advanced electronics require ferroelectric materials with high dielectric response. Lead-free (1 − x)K 0.5 Na 0.5 NbO 3 -xLiNbO 3 (KNN-xLiN) ceramics with x = 0.01, 0.03, and 0.05 were produced using a solid-state method, resulting in a greater dielectric constant, a lower impedance, and an increased conductivity. Compared to conventional ferroelectrics, KNN-0.01LiN ceramics have a greater activation energy (E r e l ) of 1.33 eV and a large σ a c value of 10 − 3 − 10 − 2 S/m in the frequency range of 20 Hz–1 MHz. The peak that corresponds to the orthogonal–tetragonal (T O − T ) phase shifts toward the lower temperature side and the peak that corresponds to T T − C shifts toward the higher temperature side as dopant percentage increases in the KNN-xLiN ceramics. The observed data may provide light on a key member of the team involved in the creation of upgraded ferroelectrics with improved performance. This result sheds light on the process underlying the improved characteristics of K 0.5 Na 0.5 NbO 3 -based ceramics and may lead to the development of high performance ferroelectrics that will benefit a variety of functional materials. [ABSTRACT FROM AUTHOR]

We present a systematic approach for synthesizing 3D-printable all-dielectric devices. Inverse design approaches yield, in many cases, configurations with a continuous range of dielectric constant values. However, 3D printer resins usually provide a very limited set of such values; commonly, a single resin and air are the only available materials. We propose a methodology for transforming a device with a continuous range of material properties to a manufacturable one, while preserving the device's performance as close as possible to the continuous case. We develop an algorithm that takes the continuous range of dielectric constant profile as input and generates a binary and connected device that can be 3D-printed using a single resin. Our methodology advances state-of-the-art algorithms by using manufacturable configurations of prescribed local air/resin composition to realize each designed dielectric material instead of being limited to a predetermined shape. The additional degrees of freedom provided by our approach may be particularly useful in devices of conformal complex-shaped dielectric constant profiles. We demonstrate the proposed methodology by designing a 3D-printable wide-angle refraction metagrating with performance very close to the inversely designed device of a continuous dielectric constant profile. The approach can be adapted to accommodate three-dimensional devices and other applications. [ABSTRACT FROM AUTHOR]

Electromagnetic applications of composites often impose constraints on the internal electric fields, such as an upper limit on the field strength to prevent local heating or dielectric breakthrough. However, owing to heterogeneity, the local fields in a composite differ from those in a homogeneous material. Moreover, they are accessible neither by experiment nor by effective medium theories, at least for arbitrary microstructures. In this work, we use numerical simulations to evaluate the electric field distribution and the effective permittivity for 3D systems of monodisperse impenetrable spheres dispersed in a continuous matrix phase. We restrict ourselves to loss-free dielectric materials and to a random spatial distribution of particles. Samples are placed in a parallel plate waveguide and exposed to a transverse electromagnetic wave. The local field amplitudes are calculated via the finite element method and are normalized to those of a homogeneous sample exhibiting the same effective permittivity and geometry. We analyze the distribution of the local electric field strength in both constituents, namely, particles and matrix. Thus, we evaluate mean values and standard deviations as well as the field strengths characterizing the highest and lowest percentiles. Increasing particle concentration or permittivity enhances heterogeneity, and so the local electric field strength in some domains can become much higher than its average value. The methods we apply here can also be used in further investigations of more complex systems, including lossy materials and agglomerating particles. [ABSTRACT FROM AUTHOR]

Ultrathin (1–4 nm) films of wide-bandgap semiconductors are important to many applications in microelectronics, and the film properties can be sensitively affected by defects especially at the substrate/film interface. Motivated by this, an in vacuo atomic layer deposition (ALD) was developed for the synthesis of ultrathin films of Ga2O3/Al2O3 atomic layer stacks (ALSs) on Al electrodes. It is found that the Ga2O3/Al2O3 ALS can form an interface with the Al electrode with negligible interfacial defects under the optimal ALD condition whether the starting atomic layer is Ga2O3 or Al2O3. Such an interface is the key to achieving an optimal and tunable electronic structure and dielectric properties in Ga2O3/Al2O3 ALS ultrathin films. In situ scanning tunneling spectroscopy confirms that the electronic structure of Ga2O3/Al2O3 ALS can have tunable bandgaps (Eg) between ∼2.0 eV for 100% Ga2O3 and ∼3.4 eV for 100% Al2O3. With variable ratios of Ga:Al, the measured Eg exhibits significant non-linearity, agreeing with the density functional theory simulation, and tunable carrier concentration. Furthermore, the dielectric constant ε of ultrathin Ga2O3/Al2O3 ALS capacitors is tunable through the variation in the ratio of the constituent Ga2O3 and Al2O3 atomic layer numbers from 9.83 for 100% Ga2O3 to 8.28 for 100% Al2O3. The high ɛ leads to excellent effective oxide thickness ∼1.7–2.1 nm for the ultrathin Ga2O3/Al2O3 ALS, which is comparable to that of high-K dielectric materials. [ABSTRACT FROM AUTHOR]

This study explores various models of semiconductor dielectric functions, with a specific emphasis on the large wavenumber spectrum and the derivation of the screened exchange interaction. Particularly, we discuss the short-range effect of the screened exchange potential. Our investigation reveals that the short-range effect originating from the high wavenumber spectrum is contingent upon the dielectric constant of the targeted system. To incorporate dielectric-dependent behaviors concerning the short-range aspect into the dielectric density functional theory (DFT) framework, we utilize the local Slater term and the Yukawa-type term, adjusting the ratio between these terms based on the dielectric constant. Additionally, we demonstrate the efficacy of the time-dependent dielectric DFT method in accurately characterizing the electronic structure of excited states in dyes and functional molecules. Several theoretical approaches have incorporated parameters dependent on the system to elucidate short-range exchange interactions. Our theoretical analysis and discussions will be useful for those studies. [ABSTRACT FROM AUTHOR]

In recent years, the exploration of solar absorbers has grown in favor due to the scarcity of energy. Here, we propose an absorber with an array of a circular ring surrounding disk (RSD) for solar energy capture. The novel structure keeps above 93.5% absorption with an average absorption of 96.95% in wavelengths from 300 to 4000 nm. Meanwhile, the proposed absorber is advantageous in that the structure is generalizable to other metals and dielectric materials. Furthermore, the data results show that the absorber has polarization-independent properties as well as maintaining >90% absorption in the considered wavelength range up to an incidence angle of 52° and >95% absorption at large process tolerances. Finally, the excellent absorption under the AM1.5 solar spectrum demonstrates the RSD absorber's ability to capture solar energy. These results show the potential of the absorber for applications in electromagnetic invisibility cloaking, thermal emitters, and solar energy capture and conversion. [ABSTRACT FROM AUTHOR]

In a class of high quality (Q-) factor dielectric resonators with low radiative losses, including popular whispering-gallery mode (WGM) resonators with high azimuthal mode numbers, due to high confinement of modal field in dielectric, the Q-factor is limited by the value of inverse dielectric loss tangent of dielectric material. Metal enclosures necessary for device integration only marginally affect the Q-factor while eliminating the residual radiative loss and allowing the optimization of input and output coupling. While very high Q-factors ∼ 200 000 are available in sapphire WGM resonators in X-band, at millimeter wave frequencies increasing dielectric loss limits the Q-factor to much smaller values, e.g. ∼50000 and ∼25000 for quasi-TE and quasi-TM modes, correspondingly, at 36 GHz. The use of distributed Bragg reflection (DBR) principle allows to push modal energy outside dielectric while also isolating it from Joule losses in metallic enclosure walls. Very high Q ∼ 600 000 > --> t g δ has been demonstrated in X-band [C. A. Flory and R. C. Taber, IEEE Trans. Ultrason., Ferroelectr., Freq. Control 44, 486–495 (1997).] at the expense of impractically large dimensions. In this work, we report on the assembly and testing of a compact Ka-band sapphire distributed Bragg reflector cavity characterized with Q-factor seven times larger than one predicted by the material's dielectric loss at the frequency of interest. An intrinsic Q-factor of ∼ 200 000 is demonstrated at 36 GHz for the lowest order TM-mode of a sapphire DBR. The resonator has 50 cm 3 volume, smaller than previously demonstrated DBRs. [ABSTRACT FROM AUTHOR]

AgNbO3 (AN)-based lead-free antiferroelectric ceramics are widely studied for their use as dielectric capacitor materials. In this study, Eu3+-doped AN ceramics were prepared and the results show that Eu3+ diffused into the AN lattice. The ceramics were formed by M1 and M2 phases coexisting at room temperature, as distinct from the M1 (M: monoclinic) phase of pure AN. Electrical properties and structural characterization showed that the antiferroelectric stability of the ceramics increases with the increase in Eu3+ levels. At room temperature, Ag0.94Eu0.02NbO3 ceramic exhibited a good energy storage density of 5.3 J/cm3 and a high efficiency of 71.9%. When the temperature rises from room temperature to 140 °C, the efficiency of the sample decreases from 80.4% to 67.1% and Wr decreases from 2.1 to 2.0 J/cm3, which indicates that the sample has good temperature stability. The time constant (t0.9) of this sample was less than 60 ns and the power density (PD) was 51.3 MW/cm3, indicating excellent charge–discharge capabilities. This novel ceramic is expected to be used as a new dielectric capacitor material for pulsed power supplies. [ABSTRACT FROM AUTHOR]

Thermally stimulated discharge (TSD) technique is a traditional method in dielectric research, especially for electrets. However, in conventional open-circuit and short-circuit TSD techniques, it is difficult to distinguish the surface charge and body charge of dielectric materials. In particular with the test of polymer electrets, the deformation of the polymer film may take place during the measurement process, which will affect the accuracy of the experiment results. In this paper, a glass-assisting TSD (GA-TSD) technique is proposed to solve the above problems. The feasibility of the experimental technique is verified with the GA-TSD spectra of fluorinated ethylene-propylene copolymer electret films. In addition, their theory analysis is also accomplished. The influences of glass thickness, glass dielectric property, and metallizing on the glass on GA-TSD spectra are investigated. The results prove that the GA-TSD spectra can clearly distinguish the difference between surface charge and body charge according to the current direction. The quartz glass with the lowest dielectric constant is best suitable for the GA-TSD technique. The influence of the glass thickness and metallizing on the glass on GA-TSD spectra is little. [ABSTRACT FROM AUTHOR]

Electromagnetic metasurfaces can achieve effective control of electromagnetic waves and achieve effects such as blocking, enhancing, reflecting, transmitting, or deflecting electromagnetic waves, possessing electromagnetic properties that go beyond traditional materials. Existing research indicates that the dielectric substrate of metasurfaces has a significant impact on their electromagnetic properties. Increasing the substrate thickness will be beneficial for expanding the impedance bandwidth of the metasurface, and changes in dielectric constant will also have some impact on the operating frequency and bandwidth of the metasurface. A metasurface based on an air substrate was proposed through the research of dielectric materials. In addition, an ultrawideband, miniaturized, and high-gain metasurface antenna based on an air substrate is designed. The overall size of the designed antenna is 0.5λL × 0.5λL (where λL represents the wavelength at the lowest working frequency in free space). The measured results indicate that the proposed antenna exhibits a −10 dB impedance bandwidth of 74.3% (2.53–5.52 GHz) and a peak boresight gain of 10.1 dBi. [ABSTRACT FROM AUTHOR]

Glassy films of methyl-m-toluate have been vapor deposited onto a substrate equipped with interdigitated electrodes, facilitating in situ dielectric relaxation measurements during and after deposition. Samples of 200 nm thickness have been deposited at rates of 0.1 nm/s at a variety of deposition temperatures between 40 K and Tg = 170 K. With increasing depth below the surface, the dielectric loss changes gradually from a value reflecting a mobile surface layer to that of the kinetically stable glass. The thickness of this more mobile layer varies from below 1 to beyond 10 nm as the deposition temperature is increased, and its average fictive temperature is near Tg for all deposition temperatures. Judged by the dielectric loss, the liquid-like portion of the surface layer exceeds a thickness of 1 nm only for deposition temperatures above 0.8Tg, where near-equilibrium glassy states are obtained. After deposition, the dielectric loss of the material positioned about 5–30 nm below the surface decreases for thousands of seconds of annealing time, whereas the bulk of the film remains unchanged. [ABSTRACT FROM AUTHOR]

Antiferroelectric and ferroelectric materials are prominent non-linear dielectric materials with significant applications across various fields. To fully understand their electrical properties, it is crucial to accurately discriminate the two phases, especially in compositions with the coexistence of antiferroelectric and ferroelectric phases. In this study, we propose an easy method for differentiating domain structures from phase coexistence based on split outskirt reflections. The proposed method addresses existing limitations in the spatial phase distribution and lays the groundwork for understanding their structure–property relationships. [ABSTRACT FROM AUTHOR]

This paper reviews the evolution of the charge pumping (CP) technique and its applications from the micrometer-scale to the atomic-scale device era. We describe the more significant milestones of the CP technique (CPT) over the past couple of decades, giving insight into its potentialities. We start with the most popular one "traditional or conventional CP" and follow up with its different extensions in various fields like transistor reliability and radiation damage characterizations in devices fabricated with old and new semiconductor and dielectric materials. We show its easy adaptability for transistors with specific geometries. Advantages, weaknesses, as well as future tendencies of CPT and its variants, are also discussed. [ABSTRACT FROM AUTHOR]

In this article, a compact triple‐band frequency‐tunable (FT) hexagonal‐shaped graphene antenna through a machine learning (ML) approach for terahertz (THz) application is presented. The proposed THz antenna is designed on a polyamide (∈r=3.5$$ {\in}_r=3.5 $$) substrate with a thickness of 10 μm, and graphene is used as an antenna radiator. The size of the substrate is 38 × 46 μm2. The FT is achieved by changing the chemical potential of graphene material. The performance of the proposed THz antenna has been investigated, and the impacts of several conducting materials like gold, aluminum, copper, and graphene and dielectric materials like Rogers RT/duroid 5880, polyamide, quartz, and SiO2 are explored. The proposed THz antenna provides three operating bands. The frequency of operation in Band‐1 is 2.51–5.05 THz, Band‐2 is 5.99–7.43 THz, and Band‐3 is 7.94–9.63 THz. The bandwidth in Band‐1, Band‐2, and Band‐3 are 2.54, 1.44, and 1.69 THz, respectively. The % of impedance bandwidth in Band‐1, Band‐2, and Band‐3 are 67.19%, 24.02%, and 21.28% respectively. The proposed antenna has a maximum peak gain of 5 dBi. The proposed antenna is optimized through various ML algorithms like random forest (RF), extreme gradient boosting (XGB), K‐nearest neighbor (KNN), decision tree (DT), and artificial neural network (ANN). The RF algorithm gives more than 99% accuracy compared to other ML algorithms and accurately predicts the S11 of the proposed antenna. The proposed THz antenna would be suitable for applications related to imaging, medical, sensing, and ultra‐speed short‐distance communication applications in the THz region. [ABSTRACT FROM AUTHOR]

High‐frequency dielectric materials have been widely and rapidly applied in areas such as automotive radar, Internet of Things, artificial intelligence, and quantum computing. Currently, the challenge in high‐frequency dielectric materials lies in reducing the dielectric constant (Dk) and dielectric loss (Df) without sacrificing its mechanical properties. This study addresses this challenge by introducing air, as the most common "low dielectric factor," into the polymer matrix in the form of hollow glass microspheres. Meanwhile, the reactive vinyl groups were also introduced onto the surface of the hollow glass microspheres, enabling an interfacial chemical reaction between the side vinyl groups of polybutadiene and its surface so that the organic–inorganic interface compatibility and interface peel strength are simultaneously improved. Consequently, the minimum Dk of 1.29 and Df of 0.0012 in 3–18 GHz are achieved, and the interface peel strength also reaches 0.65 N/mm. Molecular dynamics simulations, analysis of dielectric properties, and interface peel strength reveal the influence of hollow glass microspheres' morphology and chemical structure on their high‐frequency dielectric performance and adhesive strength. This paper provides effective strategies for the structural design and preparation of high‐frequency, low‐dielectric composites, contributing to the further development of next‐generation microwave communication devices towards higher frequencies and faster information transmission. [ABSTRACT FROM AUTHOR]

Flexoelectricity, a universal electromechanical coupling effect present in all dielectric materials, has garnered significant theoretical and experimental interest in recent years, particularly in ferroelectric perovskite oxides. However, nitride-based materials have received considerably less attention. In this Letter, we report the observation of direct flexoelectric effect in plasma-enhanced chemical vapor deposition silicon nitride thin film with a thickness of 200 nm. From three-point bending tests, we determined the effective flexoelectric coefficient of Si3N4 to be 1.64 ± 0.22 nC / m. Additionally, the measured flexoelectric-induced voltages are consistent with finite element computational models. This observation of the flexoelectric coupling effect could contribute to the development of silicon nitride-based micro-scale devices. [ABSTRACT FROM AUTHOR]

Contact Electro‐Catalysis (CEC) using commercial dielectric materials in contact‐separation cycles with water can trigger interfacial electron transfer and induce the generation of reactive oxygen species (ROS). However, the inherent hydrophobicity of commercial dielectric materials limits the effective reaction sites, and the generated ROS inevitably undergo self‐combination to form hydrogen peroxide (H2O2). In typical CEC systems, H2O2 does not further decompose into ROS, leading to suboptimal reaction rates. Addressing the generation and activation of H2O2 is therefore crucial for advancing CEC. Here, we synthesized a catalyst by loading the dielectric material polytetrafluoroethylene (PTFE) onto ZSM‐5 (PTFE/ZSM‐5, PZ for short), achieving uniform dispersion of the catalyst in water for the first time. The introduction of an FeIII‐initiated self‐cycling Fenton system (SF‐CEC), with the synergistic effects of O2 activation and FeIII‐activated H2O2, further enhanced ROS generation. In the FeIII‐initiated SF‐CEC system, the synergistic effects of ROS and protonated azo dyes enabled nearly 99 % degradation of azo dyes within 10 minutes, a sixfold improvement compared to the CEC system. This represents the fastest degradation rate of methyl orange dye induced by ultrasound to date. Without extra oxidants, this system enabled stable dissolution of precious metals in weakly acidic solutions at room temperature, achieving 80 % gold dissolution within 2 hours, 2.5 times faster than similar CEC systems. This study also corrects the unfavorable perception of CEC applications under acidic conditions, providing new insights for the fields of dye degradation and precious metal recovery. [ABSTRACT FROM AUTHOR]

The first objective of this research is to develop two effective techniques for solving inhomogeneous problems in a rectangular waveguide with several circular dielectric and hollow layers. The cross section consists of a four-layer periodic circular structure with alternating dielectric and hollow layers. We assume that the dielectric profile is different in each circular dielectric layer. The first technique enables the calculation of the dielectric profile and the elements of the matrices of circular dielectric layers by using the image method. The second alternative technique improves the first technique by using the $ \omega _{ \varepsilon } $ ω ε function as well as the image method. The second objective is to examine the influence of this discontinuous cross section on the output field. The contribution of the proposed techniques is important to improve the mode model method especially in the case of a large number of circular dielectric and hollow layers in the cross section. The application is useful for an inhomogeneous cross section with several circular dielectric and hollow layers in millimeter regime. [ABSTRACT FROM AUTHOR]

Technological breakthroughs in this era of 5G and IoT entail the sustainable fabrication of integrable and multifunctional compact devices using low-loss microwave dielectric materials. Nowadays, the miniaturization of devices using magnetodielectric materials fabricated through a green and sustainable cold sintering process has expanded the scope of applications in various fields of modern communication. Cold sintering, a novel ultra-low-energy sintering technique based on pressure solution creep mechanisms, is a potential strategy with impressive savings in energy, time, and cost. This present work highlights the dielectric response and microstructure of (1−x) Gd3Fe5O12-x SnF2 (x = 0.2, 0.3, 0.4, 0.5 volume fraction) ceramic composites fabricated via a water-assisted cold-sintering process at a temperature of 150 °C under 300 MPa pressure for 30 min. The novelty of using SnF₂ with Gd₃Fe₅O₁₂ in a cold sintering process lies in its ability to enhance densification, lower hygroscopicity, moderate relative permittivity (18.6 at 900 MHz), low loss (∼10−2), and its low melting temperature of 216 °C. This innovative approach improves the properties of ceramic composites at significantly low temperatures, showing the potential for sustainable and efficient fabrication. Microstructural studies of these composites indicate that, as the volume fraction of SnF₂ increases, the densification of the composites rises to 94.6% due to consecutive mechanisms of particle rearrangement, compaction, dissolution, and diffusion of SnF₂ through the liquid phase at the initial stage, followed by the evaporation of the liquid phase, resulting in the precipitation of the supersaturated phase at pores and interfaces, and, finally, the melting of SnF₂ forms a glassy phase around the grain boundaries. After cold sintering, the relative density of (1−x) Gd3Fe5O12-x SnF2 composites ranges from 82.4% to 94.6% as x changes from 0.2 to 0.5. The relative permittivity (εr) of these (1−x) Gd3Fe5O12-x SnF2 ceramic composites ranges from 10.1 to 12.6 with a dielectric loss (tan δ) of the order of 10−2 at 900 MHz. Hence, water and SnF2-assisted cold sintering is an efficient fabrication route for compact and densified magneto-dielectric ceramic GdIG-SnF2 composites with electromagnetic parameter suitable for microwave applications like miniaturized antennae. [ABSTRACT FROM AUTHOR]

In addition to traditional rubber applications, 1,4‐cis‐polyisoprene (cis‐PI) has been utilized in wearable electronics. While synthetic PI typically exhibits lower durability compared to natural rubber (NR), high‐molecular‐weight cis‐PI compensates by offering improved mechanical properties and chemical resistance. The group proposes using a commercial cis‐PI with high molecular weight of 250 000 g mol−1 (PI250K‐C) grafted onto modified nanoparticle structures including silicon dioxide (mSiO2), rutile titanium dioxide (mRTiO2), and anatase titanium dioxide (mATiO2) as an insulator in organic field effect transistors (OFETs) due to its naturally low dielectric constant. The nanoparticles are pretreated with a coupling agent to improve adhesion and prevent aggregation. Rubber composite films, designated X%‐mY‐PI250K‐C (where X = 10, 20, 30% and Y = mSiO2, mRTiO2, mATiO2), are fabricated using sulfur vulcanization. The modified films demonstrate excellent mechanical stress (1.15 ± 0.1 MPa) and elasticity, enduring 50 loading–unloading cycles without residual strain. In contrast, rubber composites produced from simple blending show half the mechanical stress at 0.7 ± 0.3 MPa, which is attributed to nanoparticle agglomeration observed in SEM and EDX results. Additionally, mRTiO2 nanoparticles significantly increase the dielectric constant of PI250K‐C from 2.12 to 12.93, enhancing electrical performance for TFT applications. This study underscores the effectiveness of the “grafting to” approach for producing robust rubber composites, highlighting the importance of nanoparticle selection and fabrication precision for stretchable organic electronics. [ABSTRACT FROM AUTHOR]

Highlights Regulating the dielectric properties of base stations is crucial for advancing 5G technology. This study presents the preparation of a series of graphene/polypropylene (PP) composites by blending various types and concentrations of graphene with PP using a melt blending process. The effect of different graphene types (graphene oxide, multilayer graphene, and exfoliated graphene) and concentrations (0.1, 0.5, 1, and 2 wt%) on the composites was characterized using scanning electron microscope (SEM), X‐ray diffraction (XRD), differential scanning calorimeter (DSC), impedance analyzer, rotational rheometer, and thermal gravimetric analyzer (TGA). Results show that high shear force and temperature during preparation ensure the mechanical and thermal properties of the composites. Specifically, the permittivity decreased by up to 18% with the incorporation of 1% multilayer graphene (MGE). The optimal performance was achieved with MGE compared to graphene oxide (GO) and exfoliated graphene (GE), as the composites exhibited enhanced mechanical strength, thermal stability, and lower permittivitys. This work suggests significant application prospects for PP composite materials in the 5G field due to the excellent characteristics of graphene. Graphene significantly reduces the permittivity of polypropylene. Strong interfacial bonding exists between moderate amounts of graphene and PP. Graphene boosts substrate crystallization to reduce permittivity. Composite permittivity rises with filler's permittivity increase. [ABSTRACT FROM AUTHOR]

As the feature size of microelectronic circuits is scaling down to nanometer order, the increasing interconnect crosstalk, resistance-capacitance (RC) delay and power consumption can limit the chip performance and reliability. To address these challenges, new low-k dielectric (k < 2) materials need to be developed to replace current silicon dioxide (k = 3.9) or SiCOH, etc. However, existing low-k dielectric materials, such as organosilicate glass or polymeric dielectrics, suffer from poor thermal and mechanical properties. Two-dimensional polymers (2DPs) are considered promising low-k dielectric materials because of their good thermal and mechanical properties, high porosity and designability. Here, we report a chemical-vapor-deposition (CVD) method for growing fluoride rich 2DP-F films on arbitrary substrates. We show that the grown 2DP-F thin films exhibit ultra-low dielectric constant (in plane k = 1.85 and out-of-plane k = 1.82) and remarkable mechanical properties (Young's modulus > 15 GPa). We also demonstrated the improved performance of monolayer MoS2 field-effect-transistors when utilizing 2DP-F thin films as dielectric substrates. Low-dielectric-constant (k < 2) materials are needed to reduce crosstalk, delay and power consumption in microelectronic circuits. Here, the authors report the growth of low-k 2D fluoride-rich polymer thin films, showing good mechanical properties and their application for the realization of 2D MoS2 transistors with improved performance. [ABSTRACT FROM AUTHOR]

Polypropylene (PP)‐based dielectric film capacitors cannot meet the rapid development requirements of electromagnetic energy equipment because of their low energy storage density (Ue). The development of new dielectric materials is hampered by the trade‐off between high energy storage properties and thin film processibility for capacitors. This study proposes a strategy to improve the comprehensive energy storage properties of PP films by reconciling the trade‐offs not only between their polarity and crystallinity but also between their energy storage and processing performance. In this approach, a trifluoroethyl methacrylate (TFEMA) modified PP film is fabricated at the kilogram scale. The TFEMA units regulate PP crystallization in the α‐phase, resulting in improved mechanical, dielectric, and energy storage performance. The optimal PP‐g‐TFEMA film exhibits a remarkable breakdown strength (Eb) of 865 MV m−1 and a record Ue of 8.2 J cm−3 at over 90% discharge efficiency. The promising thin film processibility, excellent self‐healing, and long‐term reliability of PP are finely preserved in the aluminum (Al) coated PP‐g‐TFEMA film. These findings present a novel avenue to significantly increase the Ue of film capacitors for long‐term service not only in academia but also in industry. [ABSTRACT FROM AUTHOR]

Highlights With the advancement of technology, the demand for high‐performance stealth materials with complex structures has increased significantly. This study explores the integration of design, manufacturing, and evaluation of stealth structures using fused deposition modeling (FDM) combined with advanced absorbing materials. Focusing on nylon‐based filaments optimized for broadband absorption, the research is inspired by the microstructure of the weaver ant's back shell to create a thin‐layer, wideband absorbing structure with wide‐angle response, employing the trust region algorithm. This integration of high dielectric loss materials, bionic design, and FDM technology enhances manufacturing efficiency and reduces the structure's thickness. The resulting structure achieves broadband absorption from 3.56 to 40 GHz, excellent angular adaptability, and mechanical robustness. Compared to gradient cell structures, it reduces thickness by 33% and extends the absorption frequency range by 5%. This approach offers a lightweight, high‐performance solution for next‐generation stealth applications. Biomimetic inspired design‐manufacturing‐evaluation integration. Trust domain algorithm optimization. Improve absorption by combining the macro structure and micro materials. Additive manufacturing cross‐enabled functional material design. [ABSTRACT FROM AUTHOR]

Most molecules and dielectric materials have characteristic bond vibrations or phonon modes in the mid-infrared regime. However, infrared absorption spectroscopy lacks the sensitivity for detecting trace analytes due to the low quantum efficiency of infrared sensors. Here, we report mid-infrared photothermal plasmonic scattering (MIP-PS) spectroscopy to push the infrared detection limit toward nearly a hundred molecules in a plasmonic nanocavity. The plasmon scattering from a nanoparticle-on-film cavity has extremely high sensitivity to the spacing defined by the analyte molecules inside the nanogap. Meanwhile, a 1000-fold infrared light intensity enhancement at the bond vibration frequency further boosts the interaction between mid-IR photons and analyte molecules. MIP-PS spectroscopic detection of nitrile or nitro group in ~130 molecules was demonstrated. This method heralds potential in ultrasensitive bond-selective biosensing and bioimaging. [ABSTRACT FROM AUTHOR]

Terahertz (THz) electric inductive‐capacitive (ELC) resonant metamaterials (MMs) are well established tools that can be used to detect the presence of dielectric material (e.g., nanoparticles, bioparticles, etc.) spread on their surfaces within the gap of the capacitive plates of a nanoantenna array. In THz spectroscopy, the amount of the red shift in the resonance frequency (ΔF) plays an important role in the detection of nanoparticles and their concentration. We introduce a new LC resonant MM architecture in the ELC category that maximizes dielectric sensitivity. The newly proposed architecture has an octahedral structure with uniform capacitive gaps at each forty‐five‐degree interval, making the structure super‐symmetric and polarization independent. The inductor core is condensed into a central solid circle connecting all the eight lobes of the octahedron, thereby completing the LC circuit. This ELC resonator has very large active areas (capacitor‐gaps), with hotspots at the periphery of each unit cell. The MM structure is repeated in a clustered fashion, so that the peripheral hotspots are also utilized in dielectric sensing. This results in enhancing the quality factor of MM resonance, as well as in increasing ΔF. The research comprises a combination of rigorous system‐level simulations along with THz impedance spectroscopy laboratory experiments. We achieved a highly sensitive MM sensor with sensitivity reaching 1600 GHz/RIU. This sensor is fully CMOS compatible and has promising potential applications in high‐sensitivity bio‐sensing, characterization of nanoparticles, and ultra‐low‐concentration dielectrics detection, as well as in sensing differential changes in the composition of substances deposited on the metasurface. [ABSTRACT FROM AUTHOR]

Highlights Polymer‐based composites with high energy storage density are essential for flexible dielectric capacitors. Herein, a series of poly(vinylidene fluoride) (PVDF)‐based nanocomposite films are prepared by incorporating multidimensional hybrid fillers composed of BaTiO3 nanoparticles (BT NPs), Al2O3 nanofibers (Al2O3 NFs) and hexagonal boron nitride nanosheets (BNNSs), where BT NPs are embedded and homogeneously dispersed in Al2O3 NFs using electrospinning technique. Benefiting from Al2O3 and BNNSs with wide‐band gap and high thermal conductivity as well as BT with high dielectric constant, a prominent enhancement of dielectric constant, breakdown strength and thermal conductivity are achieved in BT@Al2O3‐BNNSs/PVDF nanocomposite. As a consequence, the energy storage density of BT@Al2O3‐BNNSs/PVDF nanocomposite reaches 13.1 J/cm3 at 490.9 kV/mm, which is 3.2 times that of PVDF and approximately 2 times that of PVDF nanocomposites using only BT@Al2O3 or BNNSs as fillers. This work highlights the synergistic effects of nanofillers with different characteristics, and provides a promising strategy for flexible dielectric materials towards energy storage application. Designed multidimensional fillers containing BaTiO3 NPs, Al2O3 NFs, and BNNSs. Co‐enhanced dielectric and thermal conductivity properties of PVDF composites. Excellent energy storage density of 13.1 J/cm3. [ABSTRACT FROM AUTHOR]

\nHIGHLIGHTSLow-dimensional carbon materials have been widely used to enhance the properties of polymer composites. However, low-dimensional carbon materials are easy to agglomerate in polymer matrix due to their nanoscale effects. It may be a good choice to use the coordination effect between nanomaterials of different dimensions to enhance the dispersion of fillers and the performance of composites. In this paper, the coordination effect between two-dimensional Ti3C2Tx MXene and one-dimensional carbon nanotubes (CNT) nanomaterials was used to prepare methyl vinyl silicone rubber (VMQ) composites with enhanced properties. The research shows that appropriate proportion of MXene and CNT can improve the dispersion of the fillers in the VMQ and optimize the conduction path, leading to enhanced interfacial polarization and micro-capacitor effect, and thus improved dielectric property of the composites. Dielectric constant of 7.85 (2.7 times of pure VMQ) was obtained in the VMQ composites, while the loss tangent was 0.00122 at 1 kHz. In addition, the mechanical properties were also improved, and the Young’s modulus value was lower than 500 kPa. The polymer composites prepared by adding nano-fillers of different dimensions display good properties, which has certain guiding significance for the high performance dielectric composites.The coordination effect between Ti3C2Tx MXene and CNT was used to prepare flexible dielectric composites.Dielectric constant of 7.85 was obtained in the VMQ composites, while the loss tangent was 0.00122 at 1 kHz.The Ti3C2Tx MXene/CNT/VMQ composites were obtained with excellent mechanical properties.The coordination effect between Ti3C2Tx MXene and CNT was used to prepare flexible dielectric composites.Dielectric constant of 7.85 was obtained in the VMQ composites, while the loss tangent was 0.00122 at 1 kHz.The Ti3C2Tx MXene/CNT/VMQ composites were obtained with excellent mechanical properties. [ABSTRACT FROM AUTHOR]

CuO ceramics were synthesized using the cold sintering process (CSP). CuO nanoparticles with an average size of ∼115 nm were employed as the starting powders. The CuO ceramic samples were fabricated under a pressure of 400 MPa at temperatures ranging from 150 to 300 °C for 30 min (CSP samples). A relative density greater than 81.9 % was achieved at temperatures ≥200 °C, which was significantly higher than that of samples prepared using the non−cold sintering process (non−CSP). By further annealing the CSP samples at ≥750 °C, the relative density increased to over 90 %. Additionally, the mean grain size of the CSP sample was slightly smaller compared to the non−CSP samples. Remarkably, at a sintering temperature of 200 °C, the CSP sample exhibited a giant dielectric permittivity of 17,000 at 1 kHz and room temperature, whereas the non−CSP samples did not exhibit such high dielectric permittivity. Furthermore, the dielectric permittivity of the CSP sample demonstrated slight frequency dependence across the range of 40–105 Hz. This research introduces a novel method for achieving giant dielectric materials at a low temperature of 200 °C. The dielectric permittivity increased further by annealing at 700–900 °C, which was attributed to the increase in relative density. The giant dielectric properties were explained using X−ray photoelectron spectroscopy, attributing them to charge hopping between Cu+ and Cu2+, the grain boundary barrier layer capacitor, and sample−electrode effects. [ABSTRACT FROM AUTHOR]

Flexoelectricity incorporating electric polarization and strain gradients exists in all dielectrics. In the present work, the function of Hamilton's principle of the elastic dielectric materials considering the flexoelectric effect is established and its stationary conditions are also obtained. A bilayer beam composed of elastic and piezoelectric parts is modeled to investigate flexoelectricity under both mechanical and electrical loads. Based on Hamilton's principle, the governing equation and boundary conditions of a piezoelectric/elastic bilayer beam with generalized supporting ends are deduced. Accordingly, the analytical solutions to the horizontal displacements are derived. It is found that the flexoelectric effects depend on the size heavily, which is dominant for the structures at nanoscale but had hardly influence on the larger ones. Moreover, the piezoelectric/elastic bilayer beam behaves much better on controlling of the bending flexibility by adjusting the thickness ratio of the two parts. It's hopeful to provide guidance for designing and optimizing nanoscale electronic devices. [ABSTRACT FROM AUTHOR]

Microwave dielectric ceramics are essential for producing microwave components, seriously affecting the development and application of wireless communication technology. In this paper, Zn1.8-xMnxSiO3.8 (0 ≤ x ≤ 0.20) ceramics were prepared by solid-phase reaction method. The sintering characteristics, phase compositions, microstructures, and dielectric properties of the materials were investigated. The addition of Mn2+ ions lowered the sintering temperature of the ceramics, and the densification temperature decreased from 1300 to 1200 ℃ as the amount of Mn2+ substitution increased. The Mn2+ substitution (x = 0–0.2) effectively formed a Zn2SiO4 solid solution without the appearance of any other secondary phases. A moderate amount of Mn2+ improves the microscopic morphology of Zn1.8-xMnxSiO3.8 ceramics and enhances their Q × f. The theoretical and relative densities of the material were maximized at x = 0.04, where the ρbulk = 4.0865 g/cm3 and ρrela = 97.7%. At x > 0.12, the grain size grows, and anomalous grains appear and increase, deteriorating the microwave dielectric properties. The Q × f values are related to the microscopic morphology and packing fraction. αobs increases from 13.360 to 13.596, the same trend as the αtheo, suggesting that εr is mainly affected by the ion polarizability. Among all the samples, the optimum microwave dielectric properties of Zn1.76Mn0.04SiO3.8 ceramics were obtained by sintering at 1275 ℃ for 3 h:εr = 6.44(at 13.153 GHz), Q × f = 71,175.7 GHz,τf = − 50.7 ppm/℃. Due to its low dielectric constant and excellent quality factor, it will become the most promising electronic substrate material. [ABSTRACT FROM AUTHOR]

This paper introduces an efficient method of moments (MoM) designed to explore electromagnetic scattering in multilayered anisotropic structures. Each layer is made up of a dielectric anisotropic material characterised by a generalised tensor for permittivity, which is unrestricted in its geometrical configuration. The authors' approach analyses each layer independently, employing the surface equivalence theorem to substitute the interfaces between layers with suitable equivalent electric and magnetic surface current densities. The authors derive the necessary surface integral equations (SIEs) for each interface by implementing the proper boundary conditions. The analysis utilises rotated dyadic Green's functions that populate the infinite space with the material properties specific to each anisotropic layer. The rotation angle corresponds to the deviation between the local principal coordinate system of the material and the global coordinate system, which is determined by diagonalising the full dielectric tensor of the respective anisotropic material given in the global coordinate system. To address the SIEs for determining the unknown equivalent electric and magnetic surface current densities, Galerkin's MoM is applied. This involves expanding the unknown surface currents using suitable basis functions, simplifying the issue to a matrix equation solved through the inversion of a block‐tridiagonal impedance matrix. The diagonal nature and sparse structure of the impedance matrix, along with an effective block‐inversion method, significantly boost computational efficiency and reduce memory demands. To demonstrate the feasibility of the proposed method, the authors present a detailed derivation of the impedance matrix for the case of non‐magnetic uniaxial anisotropic media for which the Green's functions are available in closed form. The validity and efficiency of the proposed SIE‐MoM scheme are demonstrated by comparing the results of several case studies against those found in literature and results obtained via commercial numerical codes. [ABSTRACT FROM AUTHOR]

The photon-stimulated emission of bulk electrons has been extensively studied for various types of materials, while the photodetachment of surplus surface electrons has not been fully explored. The photodetachment barrier energy is commonly defined by the surface electron affinity of material, which is typically less than the work function and more pronounced for non-conducting substrates and in environments with a continuous flux of electrons to the surface, such as in gas discharge plasmas. Herein, it is experimentally shown that the photodetachment yield of surplus electrons created by plasma-induced charging of non-conductive surfaces of dielectric materials depends on the initial surface charge density and do not correlate with the tabulated affinity values of these materials under gas discharge charging conditions. This result obtained using laser-stimulated photodetachment for fused silica, boron nitride, and alumina, is critically important for the understanding of charging and discharging dynamics, secondary electron emission, and photo emission effects affecting plasma–wall interactions relevant to surface and capacitively coupled discharges, dusty plasmas, electrostatic probe diagnostics, and applications for plasma processing of materials, plasma propulsion, and gas breakdown. [ABSTRACT FROM AUTHOR]

Flexible electrets can be used to construct eco‐friendly devices that utilize dielectric materials to measure physical parameters without requiring any power supply. By achieving detection capabilities that surpass human tactile abilities, such devices can be employed to create super‐sensing technologies, such as electronic artificial skin, based on solution processes. In this study, electret‐type particles with self‐power‐generating properties are synthesized and applied to flexible pressure sensors. Notably, an ultrafast response is achieved despite the device being flexible and fabricated using a solution process. Moreover, this technology is successfully implemented in both human and robot applications, detecting tactile signals in real‐time and serving as electronic artificial skin—a key super‐sensing aspect. These results showcase the possibilities offered by high‐performance flexible sensing technology and illuminate potential directions for future applications. [ABSTRACT FROM AUTHOR]

The rapid rise of triboelectric nanogenerators, an innovative technology for low‐frequency energy harvesting and self‐powered sensing, has increased the interest in high‐performance triboelectric materials. Enhancing the surface charge density via dielectric modulation is essential for high‐performance triboelectric nanogenerators. As the most abundant biopolymer on earth, cellulose has remarkable properties such as excellent mechanical strength, thermal stability, and tunable surface chemistry, indicating its significant application potential in the design and fabrication of triboelectric nanogenerators. Owing to its unique multiscale structure and excellent processability, cellulose holds substantial promise for dielectric modulation. This review aims to provide comprehensive insights into the rational design and tailored preparation of cellulosic materials with optimal dielectric constants. First, the multiscale structure and exceptional advantages of cellulosic materials are interpreted. A comprehensive investigation into multiscale confinement‐modulated cellulosic dielectric materials encompassing cellulosic molecules, dipoles, and fibers along with their dipoles is undertaken and the significance of interfacial polarization is explored. Furthermore, the emerging applications of cellulosic materials with superior dielectric properties in triboelectric nanogenerators, including energy harvesting, self‐powered sensing, and self‐powered medical and smart monitoring systems, are described. Finally, the challenges and future opportunities for cellulosic dielectric modulation are summarized. [ABSTRACT FROM AUTHOR]

Microwave dielectric ceramics have drawn intensive interests in recent years due to the advanced development in communication area. High‐permittivity dielectric ceramics have thus become the highlight owing to dielectric ceramics with high permittivity could meet the demand of electronic components in both stabilization and miniaturization features. Bi2(Li0.5Ta1.5)O7 shows its great potential among various high‐permittivity dielectric ceramics with a suitable permittivity and a considerable quality factor. Based on previous studies, a series of rational optimizations were conducted on Bi2(Li0.5Ta1.5)O7 to manipulate the temperature coefficient of resonant frequency (TCF) and the sintering temperature for potential Low Temperature Co‐fired Ceramic (LTCC) applications. Two distinguished ceramics were obtained, Bi2(Li0.5Ta1.5)O7–0.03Bi2O3 (sintering temperature of 850°C, εr ∼ 64.1, Qf ∼ 8510 GHz, TCF—25.3 ppm/°C) and Bi2[(Li0.5Ta1.5)0.975Ti0.05]O7–0.015Bi2O3 (sintering temperature of 980°C, εr ∼ 66.2, Qf ∼ 10 950 GHz, TCF—8.5 ppm/°C). Dielectric resonator antenna (DRA) simulation was subsequently conducted and proved the ceramics holding excellent potential for microwave applications. [ABSTRACT FROM AUTHOR]

The successful synthesis of the ceramic Bi 2-x La x FeGaO 6 powder ceramic sample with varying La content (x = 0.01, 0.03, 0.07, 0.10) were synthesized via the solid-state method. Analysis using X-ray diffraction at room temperature was carried out to examine its structure, revealing a crystallite size of approximately 22.07–50.84 nm. This size indicates the potential applications in microwave technology due to its small grain size, which has the capability to enhance microwave absorption properties. The dielectric constant of the material shows an increase with the frequency applied, in accordance with the behaviour anticipated by the dielectric HN model and Debye model. This model proposes that the material's dielectric response can be manipulated by modifying the applied frequency, making it a valuable tool in the material design for specific purposes. The full width at half maximum (FWHM) curve of the electrical modulus displayed variability, suggesting the existence of a non-Debye relaxation mechanism in the material. This indicates that the material could possess distinct electrical properties that might be beneficial for certain applications. The outcomes demonstrated a negative temperature coefficient resistance (NTCR), indicating a decrease in the material's resistance with increasing temperature. Such behaviour can be advantageous in situations where temperature variations require monitoring or regulation. The Cole-Cole plot illustrated that the grains exhibit conductive behaviour at lower frequencies, a crucial insight for comprehending the material's electrical properties. In conclusion, these results indicate that the ceramic Bi 2-x La x FeGaO 6 for x = 0.01, 0.03, 0.07, 0.1) showcases promising attributes for various applications, particularly in microwave technology and electrical conductivity. [ABSTRACT FROM AUTHOR]

The study presents a comprehensive investigation into the synthesis, characterization, and application of barium strontium titanate-calcium copper titanate (BST-CCTO) heterojunction, offering insights into their potential for high-energy-density capacitors and photocatalytic applications. It discusses the synthesis methods for BST, CCTO nanoparticles and their heterojunction. It delves into the structural analysis of prepared heterojunctions using techniques like X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The photocatalytic performance of heterojunctions, particularly in the degradation of organic dyes and pharmaceutical waste under visible light, is explored. Results demonstrate the superior photocatalytic efficiency of BST-CCTO heterojunction, i.e., B2 (99.5 % for RhB) compared to individual BST (78.4 %), suggesting potential applications in environmental remediation. This study also explores the development and properties of dielectric materials, particularly focusing on polyvinylidene fluoride (PVDF) and its composites with high-dielectric ceramics such as BST and CCTO. Various aspects of dielectric behavior, including polarization mechanisms and frequency dependence, are also discussed. Dielectric studies reveal the enhanced dielectric constant (50.93 at 1 kHz for 3 wt% loading of B3) of PBCT-3 composite as compared to pure PVDF composite (10 at 1 kHz), attributed to factors such as interface engineering, complementary electrical properties, and grain boundary effects. The mechanisms underlying the interaction between fillers and PVDF matrix are elucidated, highlighting the role of interface engineering and polarization enhancement in optimizing dielectric performance. [ABSTRACT FROM AUTHOR]

Dielectric capacitors are essential components of modern advanced electronic devices and power systems based on their ultra-fast charging and discharging speeds and supreme power densities. Nevertheless, how to comprehensively boost their energy storage density and storage efficiency is still an insurmountable challenge. Here, we report a simple micro-chemical polarizability modulation strategy that enables SrTiO 3 -based dielectric materials to achieve excellent energy storage properties. The energy density and energy efficiency are increased to as high as 76 J∙cm−3 and 72 % from 0.4 J∙cm−3 and 46.7 % of pure STO, respectively, which is the largest value in micro-substitution (less than 3 %). Our results show that the introduction of trace amounts of elements with high ionic polarizabilities (Mn, V) facilitates the increase of chemical disorder and the formation of stable and highly dynamic polar nanoregions (PNRs), which reduces the hysteresis of the polarization switching and improves the polarization at the breakdown field strength, synergistically fostering the energy storage performance. The results of X-ray photoelectron spectroscopy and scanning electron microscopy reveal that the micro-substitution of Mn and V promote the reduction of oxygen vacancies and grain size, improving the breakdown resistance and stability of the capacitor. This present approach is expected to be widely used in the development of high-performance dielectrics. [ABSTRACT FROM AUTHOR]

NiCuZn ferrites are considered key elements for the non-reciprocal transmission of electromagnetic wave signals, and are desired with low ferromagnetic resonance (FMR) linewidth to reduce insertion loss of microwave components. Herein, the impact of dielectric material Ba 3 Ti 4 Nb 4 O 21 (BTN) additive on the microstructural and electromagnetic properties of NiCuZn ferrites was investigated in detail. The results indicate that a moderate amount of BTN improved the microstructure by refining grains and reducing the porosity of NiCuZn ferrites. Besides, saturation magnetization and resistivity of NiCuZn ferrites were greatly improved, and coercivity and FMR linewidth were reduced. Particularly, the separation calculation of FMR linewidth was performed to determine the linewidth resulting from porosity and crystalline anisotropy, respectively. NiCuZn ferrites with 0.60 wt% BTN exhibited a saturation magnetization of 4976 Gs, a coercivity of 1.87 Oe, a linewidth of 125 Oe, and a resistivity of 1.57 × 107 Ω•m. The improved NiCuZn ferrites with BTN additives exhibit excellent comprehensive performance and show good application prospects in microwave components. [ABSTRACT FROM AUTHOR]

Multiferroic BaTiO 3 exhibiting ferroelectric and ferromagnetic behavior was synthesized via the high-energy ball milling of pure BaTiO 3 (BTO) powders for durations ranging from 15 to 60 min, followed by pressing and sintering at 1200 °C X-ray diffraction patterns of all synthesized samples predominantly revealed a BTO phase with a tetragonal structure and a secondary Ba 12 Fe 28 Ti 15 O 84 (BFTO) phase. The BFTO phase was formed after milling for more than 30 min because of chemical interactions between the BTO powder and milling media. Vibrating sample magnetometry confirmed the ferromagnetic nature of the sintered pellets. The specific magnetization increased with increasing milling duration, reaching a maximum value of 1.15 emu/g after 60 min of milling. This increase can be attributed to the distortion of the crystal structure and presence of a secondary phase, as confirmed by scanning electron microscopy and energy-dispersive X-ray spectroscopy. Additionally, electrical characterization revealed the dielectric nature of the materials, with relative permittivity ranging from 500 to 1800, maximum spontaneous polarization from 9.77 to 11.31 μC/cm2, coercive field from 3.86 to 11.12 kV/cm, and AC conductivity from 1 × 10−6 to 1 × 10−3 S/cm. The method described in this study is a simple and cost-effective approach to produce multiferroic materials with ferroelectric and relaxor ferroelectric behavior at room temperature, broadening their potential for technological applications. [ABSTRACT FROM AUTHOR]

With the waste of resources caused by human activities, it has gradually become an increasingly prominent social problem. The development of self-healing polymers in the field of insulation has attracted widespread attention. Develop polymer matrices with efficient healing efficiency and sound insulation properties to achieve green and sustainable resource conservation. In addition, improving the dielectric properties of intrinsic self-healing matrices has been a hot topic. In this work, we developed a new PEI matrix-modified self-healing polymer substrate that provides a breakdown field strength of 240 kV/mm and self-healing properties at room temperature, this has significantly improved the dielectric properties over other previously reported self-healing polymers. In addition to the abovementioned performance, we found significant differences in thermodynamic behavior in the synthesized end-modified polymers. By dielectric characterization (LCR), the breakdown composite can be left at room temperature for 60 min, and the material can recover 80 % of the initial properties without external intervention(This is demonstrated by the fact that its DC conductivity at 60 min of autonomous healing was significantly changed from that of the freshly electrically pierced DC conductivity and remained around 5.38 × 10−11 S/cm for a longer period of time thereafter). The microscopic morphology of the modified PEI matrix was observed by scanning electron microscopy (SEM) and EDS surface elemental analysis, which further supports the existence of metal coordination structures. These findings can further deepen the thinking of self-healing dielectric composites. The work inspired by this may break the limits and take self-healing composite dielectric materials to a new height. [ABSTRACT FROM AUTHOR]

The dielectric properties of (Ga, Al)-doped ZnO ceramics were studied by density functional theory (DFT) and experimental aspectes. In the first, the combustion method was used to prepare the pristine ZnO and Ga-, Al-doped, and codoped ZnO nanopowders, then calcined nanoparticles were characterized by x-ray diffraction technique (XRD), and field emission scanning electron microscopes (FE-SEM). Finally, the synthesized nanopowders were sintered and the dielectric properties of the ceramics were measured to reveal the effect of Ga and Al doping on ZnO. In case of the density functional theory (DFT) calculation which is conducted on the Vienna Ab initio Simulation Package (VASP) using generalized gradient approximation with Hubbard parameter (GGA + U), 4 × 2 × 2 supercells of pure ZnO and Ga-, Al-doped and codoped ZnO were modeled. The supercells were optimized, and then the density of states (DOS) were investigated. From the DFT results, doping Al and Ga shifts the Fermi level to higher states. Additionally, the semiconductive behavior of ZnO changes to a metallic character after Al and Ga doping. Thus, we found from the DFT calculation that it is possible that Al and Ga doping can improve the dielectric properties of ZnO. According to the results, we have successfully synthesized (Al, Ga)-doped ZnO ceramics. Interestingly, Ga-doped ZnO ceramics exhibited colossal dielectric response with low tanδ (about 0.83) and high ε′ (around 40,623). Ga doping in ZnO benefits dielectric properties more than Al doping and co-doping due to Ga's closer ionic radius to Zn, which minimizes lattice distortion and defects. This leads to improved stability of the ZnO lattice, reducing the formation of oxygen vacancies and enhancing dielectric performance. Therefore, it can be summarized that this work succeeds in the enhancement of dielectric properties of ZnO by Ga doping. As a result, ZnO could be a higher-efficiency dielectric material when it is doped by Ga. [ABSTRACT FROM AUTHOR]

Dielectric capacitors put forward higher requirements on the energy storage density, working stability and fatigue resistance of materials with the increasing shortage of energy. Herein, 0.8Na 0.5 Bi 0.5 TiO 3 -0.2Bi 3.25 La 0.75 Ti 3 O 12 -x%Mn (x = 0,2,4,6) thin film capacitors are designed to address above concern. The Mn ions inhibit the valence change of Ti ions and combine with oxygen vacancies to form defect dipoles, which improve breakdown strength and energy density of the films. As a result, high energy storage density of 92.7 J cm−3 and excellent efficiency of 70.2% are synchronously achieved for the 4% Mn-doped NBT-BLT film. Besides, outstanding stability of energy storage performance also exhibit over a wide range of temperature (25–200 °C) and cycle number (105). This result provides a novel strategy for the preparation of dielectric materials with high energy storage performance and high operational stability. [ABSTRACT FROM AUTHOR]

Lead-free ferroelectric ceramics with a composition of 0.7(Bi 0.5 Na 0.5) 0.7 Sr 0.3 Ti (1- x) O 3 -0.3Ba 0.94 La 0.04 (Mg 1/3 Nb 2/3) x O 3 (abbreviated as 0.7BNST (1- x) -0.3BL(MN) x , 0 ≤ x ≤ 0.12) were prepared using solid-phase sintering method, involving co-substituting at A and B sites. High recoverable energy density (W rec) of 3.54 J/cm3 and energy efficiency (η) 85.49% are achieved at an electric field of 270 kV/cm. Furthermore, these ceramics exhibited excellent temperature and cycle stability at 120 kV/cm (within 25 °C–150 °C, W rec fluctuation range <14 %; under 1∼106 cycles, the W rec fluctuation range <5 %). In terms of dielectric performance, they exhibited a high dielectric constant (ε r ∼4540), an extremely low dielectric loss tanδ of <0.04 (30 °C–300 °C), and good temperature stability with Δ ε / ε 150 °C ≤ ±15 % (−19.5 °C–233.4 °C). During the charging and discharging process, these ceramics demonstrated a high energy density (W d) of 1.2 J/cm3, a power density (P D) of 61.7 MW/cm3, and an extremely short discharge time (t 0.9) of approximately ∼0.11 μs. This study has improved the dielectric energy storage performance of BNT-based lead-free piezoelectric ceramics, making them suitable for use in pulse power devices. [ABSTRACT FROM AUTHOR]

With the rapid development of integrated circuits, TiO 2 -based colossal dielectric constant ceramics have been widely studied as a critical alternative material in MLCC (Multilayer Ceramic Capacitors). However, the preparation technique is primarily based on the traditional solid-phase reaction method. In this work, (In 0.5 V 0.5) 0.1 Ti 0.9 O 2 , (In 0.5 Nb 0.5) 0.1 Ti 0.9 O 2 , and (In 0.5 Ta 0.5) 0.1 Ti 0.9 O 2 (abbreviated as IVTO, INTO, and ITTO) ceramics were prepared by a sol-gel method. In comparison, Nb5+ (r = 0.64 Å) and Ta5+ (r = 0.65 Å) have close ionic radii, which are more susceptible to Ti4+ (r = 0.745 Å) sites substitution than V5+ of a small ionic radius (r = 0.54 Å), effectively facilitating the carrier concentration. Meanwhile, the Ta5+ has another advantage in refining the ceramic grain size to further improve grain boundary resistance. The ITTO ceramics show a colossal dielectric constant of 9.3 × 104, low dielectric loss of 0.07 (1 kHz, room temperature), and stable temperature application range for X9F (−55 °C–200 °C，Δε r /ε 25 °C ≤ ±7.5 %). The dielectric mechanism is related to the internal barrier layer capacitance (IBLC) effect. Thus, this work as a novel strategy provides an effective mean for further development of future colossal dielectric constant materials. [ABSTRACT FROM AUTHOR]

High entropy oxides with interesting physical properties can be obtained by the design of A-site cations. Herein, a series of medium entropy and high entropy perovskite ceramics (Ba 0.25 Sr 0.25 Ca 0.25 Bi 0.25)TiO 3 , (Ba 0.2 Sr 0.2 Ca 0.2 Bi 0.2 La 0.2)TiO 3 , (Ba 0.2 Sr 0.2 Ca 0.2 Bi 0.2 Na 0.2)TiO 3 and (Ba 0.2 Sr 0.2 Ca 0.2 La 0.2 Na 0.2)TiO 3 were synthesized by the solid-state method, which selected various valence elements to achieve a single-phase structure and increase the lattice distortion. The microstructure indicated that the high-entropy ceramics exhibited the same macroscopic single perovskite while the local configuration is different. Mesoscopic results show that high entropy can adjust the polarization and relaxation of ferroelectrics, so as to optimize the energy storage performance. Meanwhile, the results manifest that grain boundaries, oxygen defects and relaxation can be changed by entropy configuration. Our work proves that the properties of high entropy ferroelectric materials can be regulated by different valence states of the elements in high entropy and explores the relevant mechanism, which provides a possible opportunity for the design and application of high-entropy dielectric materials with excellent properties. [ABSTRACT FROM AUTHOR]

dielectric capacitors are highly desired in advanced high-power electrical systems owing to their fast charge-discharge capabilities, such as electromagnetic devices, high-power microwaves, and hybrid electric vehicles. While the performance of dielectric capacitors is mainly dominated by dielectric materials. (Na 0.5 Bi 0.5)TiO 3 -(Sr 0.7 Bi 0.2)TiO 3 (NBT-SBT) as well-known dielectric ceramics attracted much attention and are widely studied owing to their combining antiferroelectric and relaxor features which achieve high energy density and efficiency. However, few studies report the compositional modification of B-site in NBT-SBT dielectric ceramics. Here, we prepared a series of MgNb 2 O 6 doped NBT-SBT ceramics at B-Sites of the perovskite structure. Their phase structure, microstructure morphology structure, elemental distribution, dielectric and energy storage properties are systemically investigated. The resultant characterization showing minor doping MN into NBT-SBT ceramic decreases the polarization hysteresis generating an outstanding energy storage property. In addition, their energy-density variation of less than 10 % over a wide temperature range of −50 to 150°. The present research offers a route for designing dielectric ceramics with enhanced energy storage performance. • Synthesized pure phase NBT-SBT ceramics with varying MgNb 2 O 6. • Small additions of MgNb 2 O 6 reduced polarization hysteresis while boosting energy storage potential. • Achieved a 1.5 J cm⁻1 energy storage density with stable efficiency (83–95 %) and less than 10 % fluctuation. [ABSTRACT FROM AUTHOR]

Recent advancements in 3D printing technology have enabled the rapid production of complex structures, yet the dielectric performance of 3D printing materials and their potential for manufacturing electrical components remain insufficiently studied. In this study, a capacitor rated at 10 kV with a capacitance of 1 nF was designed and developed for high-voltage applications. During the production of the capacitor, the insulating and conductive parts were fabricated using a 3D printer. While PLA, ABS, ASA, and PETG were employed as insulating materials, aluminum was chosen as the conductive part. Theoretical calculations and the finite element method were used to validate the measured capacitance of the equipment. The performance of the prototype capacitor was analyzed through partial discharge inception voltages (PDIV), dissipation factor (tanδ), and breakdown voltage measurements. Dissipation factor measurements were performed at 2 and 4 kV voltages in the 50–400 Hz frequency range. The performance of employed materials was comparatively analyzed through experimental and simulation results. Finally, the impact of different insulating materials on the dielectric performance of the prototype capacitors was evaluated. [ABSTRACT FROM AUTHOR]