High Relative Dielectric Constant Research Articles

Enhanced energy storage performance in polyetherimide composites via oriented one-dimensional BZCT@BT core-shell filler.

The development of dielectric capacitors toward high voltage and high power density requires materials with excellent insulation and energy storage performances. In this work, a polymer dielectric with polyetherimide (PEI) as the matrix and calcium barium zirconate titanate (BZCT) coated by barium titanate fiber (BT) as the filler (BZCT@BT) was constructed. The (0.5%-10% BZCT@BT/PEI) polymer dielectric has an excellent discharge energy density (Ue) of 6.66 J/cm3 and maintains an advanced charge/discharge efficiency (η) of 93.29% when the BT content was 0.5% and the BZCT particle content was 10%. The addition of BZCT endows the polymer dielectric with a higher relative dielectric constant (εr), while BT, maintaining a lower εr than BZCT, could reduce the electric field (E) distortion caused by the dielectric mismatch between PEI and BZCT. Oriented fiber fillers increase the breakdown strength of the polymer dielectric, ultimately increasing the performance of energy storage. A new strategy for the design of energy storage polymer dielectrics was provided by this work.

Multifunctional Experimental Studies of Sm-Ion-Influenced Pseudo-Cubic Morphotropic Phase Boundary Regional BiFeO3-xSrTiO3 Ceramics for High-Temperature Applications

In this manuscript, for the first time, the exploration of the microstructural, ferroelectric, piezoelectric, and dielectric performances are measured for Sm-ion-influenced pseudo-cubic, morphotropic phase boundary (MPB) regional 0.62BiFeO3−0.38SrTiO3:xwt%Sm2O3 (BFST:xSm) ceramics with x = 0–0.25. All the compositions maintained their pseudo-cubic MPB structural stability. The composition of BFST:0.15Sm ceramics exhibited an excellent remnant polarization (Pr) of ~52.11 μC/cm2, an enhanced d33 of 101 pC/N, and the highest relative dielectric constant (ɛr) of ~1152, which are much improved as compared to that of pure BFST ceramics. BFST:0.15Sm ceramics demonstrated a Curie temperature (TC) of 378 °C. Moreover, the composition exhibited high thermal stability for d33 72 pC/N (only a 28% decrease), even at a high temperature of 300 °C. Such outstanding outcomes make BFST:0.15Sm ceramics an ideal applicant for high-temperature piezoelectric applications.

Solution-processed transparent PVP:HfO2 hybrid dielectric films with low leakage current density and high k

Organicinorganic hybrid dielectric materials have attracted significant attention owing to their capacity to integrate the mechanical and electrical characteristics of organic and inorganic components. This paper presents the deposition of high-performance polyvinylpyrrolidone (PVP): hafnium oxide (HfO2) hybrid dielectric films at low temperature using the sol-gel method. Initially, the influence of precursor components on the surface morphology of single-component dielectric films was investigated. It is observed that the addition of FSO and acetic acid can result in smoother and more uniform surfaces for PVP and HfO2, respectively. Furthermore, based on these findings, we successfully prepared PVP:HfO2 hybrid dielectric films with surface roughness below 1 nm, high transmittance above 95% in the visible range (400–760 nm), and wide optical bandgaps exceeding 5.3 eV. The formation of PVP:HfO2 cross-linked network was identified through FTIR analysis, and a mechanism was proposed. Moreover, MIM devices were fabricated to determine the insulating performance of dielectric films. We found that the PVP:HfO2 hybrid dielectric films exhibit a significant reduction in leakage current density and a substantial increase in relative dielectric constant compared to the single-component dielectric films. In addition, with the increase in PVP concentration, the leakage current density first decreases and then increases, while the relative dielectric constant first increases and then decreases. After optimization, 0.5 wt% PVP:HfO2 hybrid dielectric film exhibits a low leakage current density of 5.89×10−8 A/cm2 @1 MV/cm and a high relative dielectric constant of 32.54. PVP:HfO2 hybrid dielectric films exhibit tremendous potential for applications in the realm of high-performance transparent electronic devices.

Study on Reliability and Selection of Silicone Grease Used for Coating at the Interface Between Cable and Accessory

Silicone grease coated at the interface of cables and accessories performs a good role in lubricating and sealing during installation, but the swelling impact of silicone grease on rubber insulation of accessories greatly affects the long-term reliability of the interface between cable and accessory. Until recently, no standard has been proposed to guide accessory manufacturers in choosing the best silicone grease. In this study, nine different silicone greases that were widely used for accessories installation were chosen. First, three types of silicone greases with outstanding anti-swelling properties were tested using a silicone rubber (SiR) swelling experiment. The properties of the three silicone greases chosen were then investigated further, including electrical and mechanical properties, moisture resistance, and corona resistance. The results reveal that dimethyl silicone with high viscosity or by inserting phenyl side groups can minimize SiR swelling and then enhance its mechanical qualities. However, perfluoropolyether grease outperforms dimethyl silicone in terms of swelling resistance, chemical inertness, and excellent thermal stability. Thus, SiR coated with perfluoropolyether grease can maintain excellent mechanical properties after different aging. However, because of its high polarity, it can cause significant charge buildup at the interface between cables and accessories, particularly under direct current (dc) electrical stress. Consequently, perfluoropolyether grease will have a negative effect on the use in dc environment. Moreover, silicone greases after inorganic doping absorb moisture easily, resulting in a high relative dielectric constant that will have a negative effect on the use in a humid environment.

Boosts charge utilization and enables high performance organic solar cells by marco- and micro- synergistic method

A ternary solar cell is a typical strategy that can well compensate light absorption and effectively regulate energy levels and the morphology of active layers. However, the commonly used active materials have low relative dielectric constant, which is one of the important limitations for improving the photovoltaic performance of organic solar cells (OSCs). In this work, an insulating polymer MPFM with high relative dielectric constant is introduced into the ternary active layers to improve the performance of OSCs by synergistic effect of macro light utilization and micro interface modulation. The introduction of MPFM not only strengthened the dielectric constant of bulk heterojunctions but also enhanced the degree of crystallinity and adhesivity, promoted the exciton separation, suppressed charge recombination, and significantly accelerated charge transport. As a result with the addition of MPFM, an outstanding efficiencies of 18.21% and 18.53% are achieved for devices based on PM6:Y6:PC71BM and PM6:BTP-eC9:PC71BM, respectively. These results indicated that constructing the micro-PIN junction by using MPFM is an effective strategy to further improve the photovoltaic performance of OSCs.

High k PVP titanium dioxide composite dielectric with low leakage current for thin film transistor

Titanium dioxide (TiO 2 ) dielectric has the potential to achieve low cost and low energy consumption in the area of Thin Film Transistor (TFT) due to its high relative dielectric constant. However, the large leakage current limits its application. In this paper, Polyvinylpyrrolidone (PVP) modified TiO 2 composite dielectric was prepared by the sol-gel method with a series of PVP concentrations. With increasing PVP concentration, the roughness, thickness and band gap increased, the leakage current density first decreased and then increased, while the area capacitance and the relative dielectric constant (k) decreased. After comparison, 0.05 wt% was the optimal modification concentration. TiO 2 : 0.05 wt % PVP composite film had smooth morphology and low roughness. The leakage current density of the Metal-Insulator-Metal (MIM) device (with the composite film as the insulator layer) was as low as 6.88 × 10 −9 A/cm 2 (at 1 MV/cm), and k is 69.7. PVP modified TiO 2 composite film showed good dielectric characteristics and satisfied the development trend of low leakage current and low energy consumption devices. • Titanium dioxide and Polyvinyl pyrrolidone composite thin film was prepared by sol-gel method. • Structural and electrical parameters varied with polymer concentration. • A high k of 69.66 and a low leakage current density of 6.88 × 10 −9 A/cm 2 were achieved.

Application of Amorphous Zirconium-Yttrium-Aluminum-Magnesium-Oxide Thin Film with a High Relative Dielectric Constant Prepared by Spin-Coating.

Amorphous metal oxide has been a popular choice for thin film material in recent years due to its high uniformity. The dielectric layer is one of the core materials of the thin film transistor (TFT), and it affects the ability of charges storage in TFT. There is a conflict between a high relative dielectric constant and a wide band gap, so we solved this problem by using multiple metals to increase the entropy of the system. In this paper, we prepared zirconium-yttrium-aluminum-magnesium-oxide (ZYAMO) dielectric layers with a high relative dielectric constant using the solution method. The basic properties of ZYAMO films were measured by an atomic force microscope (AFM), an ultraviolet-visible spectrophotometer (UV-VIS), etc. It was observed that ZYAMO thin films had a larger optical band when the annealing temperature increased. Then, metal-insulator-metal (MIM) devices were fabricated to measure the electrical properties. We found that the leakage current density of the device is relatively lower and the ZYAMO thin film had a higher relative dielectric constant as the concentration went up. Finally, it reached a high relative dielectric constant of 56.09, while the leakage current density was no higher than 1.63 × 10−6 A/cm2@ 0.5 MV/cm at 1.0 M and 400 °C. Therefore, the amorphous ZYAMO thin films has a great application in the field of high permittivity request devices in the future.

Microwave and terahertz properties of porous Ba4(Sm,Nd,Bi)28/3Ti18O54 ceramics obtained by sacrificial template method

AbstractMicrowave and terahertz communications are increasingly significant, however, the lack of material information in terahertz band limits their development. Moreover, few lightweight materials with a high relative dielectric constant () are found suited for satellite communication and wearable devices. In this study, we developed lightweight porous Ba4[(Sm0.1Nd0.9)0.9Bi0.1]28/3Ti18O54 (BSNBT) ceramics exhibiting a total porosity ranging from 6.3% to 26.5% (bulk density ranging from 5.47 to 4.29 g/cm3) and relatively high ranging from 85.6 to 56.8, which were obtained by sacrificial template method using polymethyl methacrylate spheres (PMMAs) of varying average particle sizes, from 9 to 34 μm, as sacrificial materials. A high refractive index ranging between 7.5 and 8.9 and a low absorption coefficient of approximately 17 cm−1 at 0.3 THz were obtained for the porous ceramics with different total porosities derived from PMMAs with average particle sizes of 9 and 19 μm. Furthermore, effective medium and Mie scattering theories were applied to understand the effects of porous structure on the dielectric properties in microwave and terahertz frequency ranges, respectively, owing to the different wavelengths in the BSNBT matrix. The results of this study suggest that introducing a porous structure can effectively exploit lightweight microwave dielectric ceramic materials and provide valuable information on their terahertz response mechanism.

Inorganic Halide Perovskitoid TlPbI3 for Ionizing Radiation Detection

AbstractRoom temperature semiconductor detector (RTSD) materials for γ‐ray and X‐ray radiation are in great demand for the nonproliferation of nuclear materials as well as for biomedical imaging applications. Halide perovskites have attracted great attention as emerging and promising RTSD materials. In this contribution, the material synthesis, purification, crystal growth, crystal structure, photoluminescence properties, ionizing radiation detection performance, and electronic structure of the inorganic halide perovskitoid compound TlPbI3 are reported on. This compound crystallizes in the ABX3 non‐perovskite crystal structure with a high density of d = 6.488 g·cm–3, has a wide bandgap of 2.25 eV, and melts congruently at a low temperature of 360 °C without phase transitions, which allows for facile growth of high quality crystals with few thermally‐activated defects. High‐quality TlPbI3 single crystals of centimeter‐size are grown using the vertical Bridgman method using purified raw materials. A high electrical resistivity of ≈1012 Ω·cm is readily obtainable, and detectors made of TlPbI3 single crystals are highly photoresponsive to Ag Kα X‐rays (22.4 keV), and detects 122 keV γ‐rays from 57Co radiation source. The electron mobility‐lifetime product µeτe was estimated at 1.8 × 10–5 cm2·V–1. A high relative static dielectric constant of 35.0 indicates strong capability in screening carrier scattering and charged defects in TlPbI3.

Actuator Performance of a Hydrogenated Carboxylated Acrylonitrile-Butadiene Rubber/Silica-Coated BaTiO3 Dielectric Elastomer.

We synthesized silica-coated barium titanate (BaTiO3) particles with different silica shell thicknesses and evaluated the effect of silica coating on the relative dielectric properties of silica-coated BaTiO3 particles. Furthermore, composite elastomers were prepared using hydrogenated carboxylated acrylonitrile–butadiene rubber (HXNBR) with a high relative dielectric constant (εr) and silica-coated BaTiO3 particles, and their performance as an actuator was evaluated. Both εr and relative dielectric loss of non-coated BaTiO3 particles increased at low frequencies (<200 Hz) associated with ionic conduction. However, εr and relative dielectric loss were reduced for the silica-coated BaTiO3 particles with thick silica shells, indicating that silica coating reduced ion migration. The dielectric breakdown strength increased with the thickness of the silica shell; it increased up to 80 V/μm for HXNBR/silica-coated BaTiO3 particles with 20 nm-thick silica shells. The maximum generated stress, strain, and output energy density of the composite elastomer with HXNBR (with a high relative constant) and silica-coated BaTiO3 were 1.0 MPa, 7.7%, and 19.4 kJ/m3, respectively. In contrast, the values of the same parameters for a reference elastomer (acrylic/BaTiO3; with low εr) were 0.4 MPa, 6.7%, and 6.8 kJ/m3 at the dielectric breakdown strength of 70 V/μm. The results indicated that the elastomers composed of HXNBR and silica-coated BaTiO3 exhibited higher generated stress, strain, and output energy density than elastomers for conventional dielectric actuators.

Electrostatic Air Filtration by Multifunctional Dielectric Heterocaking Filters with Ultralow Pressure Drop.

In air filtration, for creating healthy indoor air, there is an intrinsic conflict between high filtration efficiency and low wind pressure drop. In this study, we overcame this conflict by developing new dielectric heterocaking (HC) filters, in which high relative dielectric constant (εr) materials were heterogeneously loaded on traditional polymer fibers. The dielectric HC filters in an electrostatic polarizing field generate a great amount of charges on their surface, leading to a strong attraction to precharged aerosol particles, and result in high filtration efficiency. Observing via a charged coupled device camera, the migration speed of aerosol smoke particles toward the polarized HC fiber exceeded those toward the unpolarized HC fiber by a factor of 6. We loaded high-εr HCs including manganese dioxide (MnO2), activated carbon, zinc oxide (ZnO), copper oxide (CuO), and barium titanate (BaTiO3) on polyurethane foams using a fast and large-scale roll-to-roll gel squeezing method. Based on the experimental results, when HCs had a εr larger than 5.1, an increased εr did not benefit electrostatic filtration efficiency for aerosol particles much, but resulted in a larger net ozone production. We suggested a MnO2-HC filter for efficient and multifunctional filtration of indoor particles, ambient ozone, and formaldehyde with only 3.8 Pa pressure drop at 1.1 m/s filtration velocity. This efficient and cost-effective dielectric HC filter opens a new avenue for the design of multifunctional filters, which will facilitate its large-scale production and commercial application in the ventilation system for healthy buildings.

3,4‐Dicyanothiophene—a Versatile Building Block for Efficient Nonfullerene Polymer Solar Cells

AbstractIn this contribution, a versatile building block, 3,4‐dicyanothiophene (DCT), which possesses structural simplicity and synthetic accessibility for constructing high‐performance, low‐cost, wide‐bandgap conjugated polymers for use as donors in polymer solar cells (PSCs), is reported. A prototype polymer, PB3TCN‐C66, and its cyano‐free analogue polymer PB3T‐C66, are synthesized to evaluate the potential of using DCT in nonfullerene PSCs. A stronger aggregation property in solution, higher thermal transition temperatures with higher enthalpies, a larger dipole moment, higher relative dielectric constant, and more linear conformation are exhibited by PB3TCN‐C66. Solar cells employing IT‐4F as the electron acceptor offer power conversion efficiencies (PCEs) of 11.2% and 2.3% for PB3TCN‐C66 and PB3T‐C66, respectively. Morphological characterizations reveal that the PB3TCN‐C66:IT‐4F blend exhibits better π–π paracrystallinity, a contracted domain size, and higher phase purity, consistent with its higher molecular interaction parameter, derived from thermodynamic calculations. Moreover, PB3TCN‐C66 offers a higher open‐circuit voltage and reduced energy loss than most state‐of‐the‐art wide‐bandgap polymers, without the need of additional electron‐withdrawing substituents. Two additional polymers derived from DCT also demonstrate promising performance with a higher PCE of 13.4% being achieved. Thus, DCT represents a versatile and promising building block for constructing high‐performance, low‐cost, conjugated polymers for application in PSCs.

Influence of oxygen pressure on the electrical properties of Mn-doped Bi0.5Na0.5TiO3BaTiO3 thin films by pulsed laser deposition

Ferroelectric Mn-doped 0.935Bi 0.5 Na 0.5 TiO 3 -0.065BaTiO 3 (MnBNBT) thin films were fabricated on (111)Pt/Ti/SiO 2 /Si substrates via pulsed laser deposition under different oxygen pressures. (100)-preferred orientation and dense films with perovskite structure were grown. The MnBNBT thin film deposited at an optimized oxygen pressure of 25 Pa exhibited a well-defined ferroelectric P - E loop with an average remnant polarization P r of 27 μC/cm 2 , a coercive field E c of 5.7 kV/mm, and a high relative dielectric constant of 1295. The leakage current characteristics were assessed, demonstrating that the ohmic conduction behaviors and Fowler-Nordheim tunneling were the main mechanisms of the MnBNBT thin films. Piezoelectric force microscopy indicated that the MnBNBT films possessed favorable local piezoelectric responses and multidomain states. The results suggest that the lead-free thin film produced is potentially applicable in ferroelectric and piezoelectric devices.

Effect of Doped Sb2O3 on the Electrical Properties of TiO2-Based Ceramics with the Dual Function of a Varistor–Capacitor

TiO2-based varistor–capacitor ceramics co-doped with fixed Nb2O5, MnO2, Sm2O3 and various content of Sb2O3 are prepared, and then the effect of Sb2O3 on electrical properties of TiO2 varistor–capacitor ceramics is investigated. The results indicate that addition of Sb2O3 effectively decreases breakdown voltage (E1mA), while having less impact on the nonlinear coefficient (α). E1mA initially increases and then decreases with Sb2O3 increasing; contrarily, relative dielectric constant (er) decreases first and then increases. It is found that composition of 98.3%TiO2-0.8%Nb2O5-0.3%MnO2-0.3%Sm2O3-0.3%Sb2O3 is obtained with a low breakdown voltage of 2.3 V/mm, nonlinear coefficient of 2.0, high relative dielectric constant of 7.6 × 104 and low dissipation factor of 0.25, which is consistent with the narrowest grain boundary barriers in the composition. The nonlinear coefficient initially increases and then decreases with increase of Sb2O3; it reaches a maximum value of 2.9 at 0.2 mol.% Sb2O3, which is consistent with the highest grain boundary barriers in the composition. In order to explain the nonlinear current–voltage characteristics, a grain boundary defect barrier model was introduced.

Análisis cristalográfico, morfológico, eléctrico, óptico y magnético del nuevo material Dy2BiFeO6

&#x0D; &#x0D; En este trabajo reportamos el análisis estructural, morfología superficial, ordenamiento magnético, respuesta dieléctrica y característica óptica de la nueva perovskita compleja Dy2BiFeO6. Las muestras fueron producidas mediante reacción de estado sólido. El análisis cristalográfico fue realizado a través de refinamiento Rietveld de los patrones experimentales de rayos X. Los resultados muestran que este material cristaliza en una perovskita ortorrómbica correspondiente al grupo espacial Pnma (#62). Por medio del ajuste de Curie-Weiss a la respuesta de la susceptibilidad magnética en función de la temperatura se estableció que el ordenamiento magnético se relaciona con una transición paramagnético-antiferromagnético con una temperatura de Weiss θ=-18,5 K, la cual es acorde con el comportamiento del inverso de la susceptibilidad en función de la temperatura, y una temperatura de Néel TN=50,8 K. La constante de Curie permitió determinar un momento magnético efectivo de 15,7 μB. Medidas de magnetización en función del campo aplicado a T=50 K, muestran un débil comportamiento histerético, que corrobora el ordenamiento magnético presente a esa temperatura. Mediciones de la constante dieléctrica en función de la frecuencia aplicada a temperatura ambiente dan como resultado una alta constante dieléctrica relativa a bajas frecuencias (ε=780). La curva de reflectancia en función de la longitud de onda revela el comportamiento típico de un material de tipo perovskita doble y permite la obtención de la brecha de energía de 2,74 eV característico de un material semiconductor.&#x0D; &#x0D; &#x0D; &#x0D;

A high dielectric constant non-fullerene acceptor for efficient bulk-heterojunction organic solar cells

A non-fullerene acceptor with a high relative dielectric constant (εr) over 9 is developed. It offers an efficiency of 8.5%, which is the best result for organic solar cells employing high εr materials. Further research should focus on morphology optimization to make high εr practically useful in devices.

Development of Ni-Ferrite-Based PVDF Nanomultiferroics

Thin-film polyvinylidene fluoride (PVDF)–spinel ferrite nanocomposites with 0–3 connectivity and varying composition, i.e., (1 − x)PVDF–xNiFe2O4 (x = 0.05, 0.1, 0.15), have been fabricated by a solution-casting route. The basic crystal data and microstructure of the composite samples were obtained by x-ray powder diffraction analysis and scanning electron microscopy, respectively. Preliminary structural analysis showed the presence of polymeric electroactive β-phase of PVDF (matrix) and spinel ferrite (filler) phase in the composites. The composites were found to be flexible with high relative dielectric constant (er) and low loss tangent (tan δ). Detailed studies of their electrical characteristics using complex impedance spectroscopy showed the contributions of bulk (grains) and grain boundaries in the resistive and capacitive properties of the composites. Study of the frequency-dependent electrical conductivity at different temperatures showed that Jonscher’s power law could be used to interpret the transport properties of the composites. Important experimental data and results obtained from magnetic as well ferroelectric hysteresis loops and the first-order magnetoelectric coefficient suggest the suitability of some of these composites for fabrication of multifunctional devices. The low electrical conductivity, high dielectric constant, and low loss tangent suggest that such composites could be used in capacitor devices.

Conformal BaTiO3 Films with High Piezoelectric Coupling through an Optimized Hydrothermal Synthesis.

Two-dimensional (2D) ferroelectric films have vast applications due to their dielectric, ferroelectric, and piezoelectric properties that meet the requirements of sensors, nonvolatile ferroelectric random access memory (NVFeRAM) devices, and micro-electromechanical systems (MEMS). However, the small surface area of these 2D ferroelectric films has limited their ability to achieve higher memory storage density in NVFeRAM devices and more sensitive sensors and transducer. Thus, conformally deposited ferroelectric films have been actively studied for these applications in order to create three-dimensional (3D) structures, which lead to a larger surface area. Most of the current methods developed for the conformal deposition of ferroelectric films, such as metal-organic chemical vapor deposition (MOCVD) and plasma-enhanced vapor deposition (PECVD), are limited by high temperatures and unstable and toxic organic precursors. In this paper, an innovative fabrication method for barium titanate (BaTiO3) textured films with 3D architectures is introduced to alleviate these issues. This fabrication method is based on converting conformally grown rutile TiO2 nanowire arrays into BaTiO3 textured films using a simple two-step hydrothermal process which allows for thickness-controlled growth of conformal films on patterned silicon wafers coated with fluorine-doped tin oxide (FTO). Moreover, the processing parameters have been optimized to achieve a high piezoelectric coupling coefficient of 100 pm/V. This high piezoelectric response along with high relative dielectric constant (εr = 1600) of the conformally grown textured BaTiO3 films demonstrates their potential application in sensors, NVFeRAM, and MEMS.

Simultaneous achievement of high dielectric constant and low temperature dependence of capacitance in (111)-oriented BaTiO3-Bi(Mg0.5Ti0.5)O3-BiFeO3 solid solution thin films

The temperature dependence of the capacitance of (111)c-oriented (0.90–x)BaTiO3-0.10Bi(Mg0.5Ti0.5)O3-xBiFeO3 solid solution films is investigated. These films are prepared on (111)cSrRuO3/(111)Pt/TiO2/SiO2/(100)Si substrates by the chemical solution deposition technique. All the films have perovskite structures and the crystal symmetry at room temperature varies with increasing x ratio, from pseudocubic when x = 0–0.30 to rhombohedral when x = 0.50–0.90. The pseudocubic phase shows a high relative dielectric constant (εr) (ranging between 400 and 560 at room temperature and an operating frequency of 100 kHz) and a low temperature dependence of capacitance up to 400°C, while maintaining a dielectric loss (tan δ) value of less than 0.2 at 100 kHz. In contrast, εr for the rhombohedral phase increases monotonically with increasing temperature up to 250°C, and increasingly high tan δ values are recorded at higher temperatures. These results indicate that pseudocubic (0.90–x)BaTiO3-0.10Bi(Mg0.5Ti0.5)O3-xBiFeO3 solid solution films with (111) orientation are suitable candidates for high-temperature capacitor applications.

High-relative-dielectric-constant bismuth–niobium–oxide films prepared using Nb-rich precursor solution

Various ceramic materials have been developed for electronic devices. Bismuth–niobium–oxide (BNO) films prepared by a chemical solution deposition (CSD) method have the cubic pyrochlore phase, high relative dielectric constant, and low tangent loss (tan δ). We found that a BNO cubic pyrochlore crystal was Nb-rich, even though its pyrochlore formula is A2B2O7. The crystallization temperature of BNO increased with increasing Nb ratio. The relative dielectric constants of BNO films were related to the Nb ratio in the precursor solution. The dielectric constant of the BNO films was 250 when the Bi and Nb ratios in BNO precursor solutions were 4 and 6, respectively, and the sintering temperature was 600 °C. In addition, the tan δ was less than 0.01 at 1 kHz, which is higher than the reported values of BNO systems despite using the CSD method. These results show that the properties of BNO films prepared by the CSD method were associated with the Nb ratio in the precursor solution. Furthermore, the dielectric characteristics indicated that the Nb-rich BNO films have potential applications in electronic devices.