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91.
Li-Feng Zhu Bo-Ping Zhang Jia-Qi Duan Bo-Wei Xun Ning Wang Yu-Cheng Tang Gao-Lei Zhao 《Journal of the European Ceramic Society》2018,38(10):3463-3471
0.7BiFeO3-0.3BaTiO3 (BFO-0.3BT) ceramics were prepared to uncover the impacts of sintering temperature (TS) and dwell time (td) on the microstructure and electrical properties. With increasing the TS or td, the grain sizes increase along with the porosity decreases, which is in favor of the alignment of dipole. However, excess TS or td are inclined to cause the volatilization of Bi2O3, which deteriorates piezoelectric properties. Because of the R-T two-phase coexistence, low defect ions concentration and porosity, as well as appropriate grain size, the excellent d33?=?208?pC/N and kp?=?35.46% as well as Pr?=?28.52?μC/cm2 were achieved in BFO-0.3BT ceramics at TS?=?1000?°C and td?=?6?h. In addition,large unipolar strain 0.13% and d33*?=?256.2?pm/V also were obtained in BFO-0.3BT ceramics at TS?=?1000?°C and td?=?6?h. This research indicates that the porosity and defect ion concentration as well as grain size also play an important role in piezoelectric properties in BFO-BT ceramics. 相似文献
92.
Xiang Lv Jiagang Wu Jianguo Zhu Dingquan Xiao Xixiang Zhang 《Journal of the European Ceramic Society》2018,38(1):85-94
Although both the phase type and fraction of multi-phase coexistence can affect the electrical properties of (K,Na)NbO3 (KNN)-based ceramics, effects of phase fraction on their electrical properties were few concerned. In this work, through changing the calcination temperature of CaZrO3 powders, we successfully developed the 0.96 K0.5Na0.5Nb0.96Sb0.04O3-0.01CaZrO3-0.03Bi0.5Na0.5HfO3 ceramics containing a wide rhombohedral-tetragonal (R-T) phase coexistence with the variations of T (or R) phase fractions. It was found that higher T phase fraction can warrant a larger piezoelectric constant (d33) and d33 also showed a linear variation with respect to tetragonality ratio (c/a). More importantly, a number of domain patterns were observed due to high T phase fraction and large c/a ratio, greatly benefiting the piezoelectricity. In addition, the improved ferroelectric fatigue behavior and thermal stability were also shown in the ceramics containing high T phase fraction. Therefore, this work can bring a new viewpoint into the physical mechanism of KNN-based ceramics behind R-T phase coexistence. 相似文献
93.
Florian Weyland Thorsten Eisele Sebastian Steiner Till Frömling George A. Rossetti Jürgen Rödel Nikola Novak 《Journal of the European Ceramic Society》2018,38(2):551-556
The stability of the electrocaloric effect under electric field cycling is an important consideration in the development of solid-state cooling devices. Here we report measurements carried out on Ba(Zr0.2Ti0.8)O3 ceramics which reveal that the adiabatic temperature change, polarization-electric field hysteresis loops and dielectric permittivity/loss show stable behavior up to 105 cycles. We further demonstrate that the loss in electrocaloric response observed after 105 cycles is associated with the migration of oxygen vacancies. As a result, the electrical properties of the material are changed leading to an increase in leakage current and Joule heating. Reversing the polarity of the electric field after every 105 cycles changes the migration direction of oxygen vacancies, thereby preventing charge accumulation at grain boundaries and electrodes. By doing so, the electrocaloric stability is improved and the adiabatic temperature remains constant even after 106 cycles, much higher than achieved in commercially available barium titanate ceramics. 相似文献
95.
《Ceramics International》2022,48(10):14301-14306
Recently, the progress of electronic devices toward miniaturization has strongly promoted development of multifunctional materials possessing multiple desirable properties. In this study, we develop and fabricate 0.93Bi0.5Na0.5TiO3-0.07BaTiO3-xEr multifunctional ceramics which show simultaneously considerable electric-field-induced strain and bright green light emission properties. With the introduction of Er3+, the ceramics gradually transform from non-ergodic relaxor phase to ergodic relaxor phase which could reversibly transform to ferroelectric phase under the electric field. As a result, with improving Er3+ content, the shape of the polarization-electric field loops of the ceramics become pinched, and it is obvious that the negative strain disappears while the positive strain gradually increases and reaches a maximum value 0.46% at x = 1.2 mol%. Besides, After the ceramics are poled, the light emission peak are greatly enhanced attributed to the decreased crystal symmetry and increased domain size, and is the strongest at x = 1.2 mol%. These results indicate that 0.93Bi0.5Na0.5TiO3-0.07BaTiO3-xEr ceramics are good candidates for developing multifunctional optoelectronic devices. 相似文献
96.
Leiyang Zhang Ziyang Wang Yang Li Peng Chen Jing Cai Yan Yan Yifan Zhou Dawei Wang Gang Liu 《Journal of the European Ceramic Society》2019,39(10):3057-3063
SnO2 doped Sr0.6(Na0.5Bi0.5)0.4TiO3 (NBT-ST) ceramics were prepared by a conventional solid-state reaction method. Their phase structures, microstructures and electrical properties were characterized in details. It is found that SnO2 doping could increase the lattice parameters, density and average grain size. A suitable amount of SnO2 can improve dielectric properties, and affect the relaxor behavior of the NBT-ST matrix, thereby it can effectively reduce the energy loss and optimize the energy storage performance. Furthermore, the energy storage properties are improved with SnO2 doping. Especially, the 1 at. % SnO2 doped NBT-ST achieves a high recoverable energy density of 2.35 J/cm3, which is mainly attributed to large maximum polarization of 43.2 μC/cm2, small remnant polarization of 5.83 μC/cm2 and high breakdown strength of 180 kV/cm. Also, relatively good temperature stability for dielectric performance and excellent fatigue resistance are observed in this composition. These properties are attractive for lead-free energy storage applications. 相似文献
97.
《Journal of the European Ceramic Society》2019,39(11):3315-3319
Multilayer ceramic capacitors (MLCCs) of lead-free NBT-based ceramics are produced and their electrocaloric effect (ECE) is characterised for the first time. Dense MLCCs with 97μm-thick active layers are successfully produced by tape casting. Dielectric permittivity measurements reveal the MLCCs to have properties similar with that reported for the corresponding bulk ceramics, including Td∼50°C and TS∼100°C. Direct ECE measurements also reveal agreement and confirm the previously reported tendency of the high-field ECE peak to shift towards TS. The highest value of ECE, ΔTmax∼1.7K is measured at 90°C under 90kV/cm. A low breakdown strength of 93kV/cm needs to be solved to realise stronger electric fields and achieve commercially viable ECE values. 相似文献
98.
The influence of an additional La0.67Sr0.33MnO3 (LSMO) magnetic phase on the structural, ferromagnetic, ferroelectric, and magnetoelectric properties of Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT) ferroelectric phase was studied for composites of (1-x)BCZT -xLSMO (x = 0, 25, 50, 75 and 100%). The ferroelectric BCZT sample showed a perovskite single phase formation with a tetragonal crystal structure of the P4mm space group, and the magnetic phase of LSMO presented a rhombohedral crystal structure of R3c space group as shown by XRD. The composite sample with 25% LSMO exhibited large ferroelectric and piezoelectric properties with remnant, saturation polarization, and coercive electric field Pr ~7.74 μC/cm2, Ps ~11.69 μC/cm2 and EC ~12.22 kV/cm with a piezoelectric coefficient d33 ~ 231 pC/N. The magnetic characterization for the composites showed that the sample containing 75% of LSMO revealed the highest remnant, saturation magnetization, and coercive field of Mr ~1.358 emu/g, Ms ~19.17 emu/g, and HC ~33.19 Oe, respectively. Moreover, it revealed the largest magnetoelectric coupling coefficient αME ~2.51 mV/cm.Oe with high coupling quality at a lower applied magnetic field. The results highlight the value of these composites as lead-free room temperature magnetoelectric sensors and actuators. 相似文献
99.
Photovoltaic performances of the bismuth-based solar cells are profoundly affected by the thin film quality of the photoactive layer. Herein, we report on various green solvent system to obtain the highly crystalline, pinhole free and homogeneously methylammonium bismuth iodide (MBI) active layer. The MBI structure prepared with tetrahydrofuran:2-ethoxy-ethanol (THF-2ETO) solvent system was found to have the best film quality. Adding 0.05 M 2ETO as the co-solvent is sufficient to produce high quality BiI3 and MBI thin films. According to the X-ray photoelectron spectroscopy (XPS) analyzes, we have demonstrated that there is an interaction between BiI3 and 2ETO according to the concentration of 2ETO added to the main THF. Our study clarifies the importance of THF-2ETO solvent system that can accelerate the evolution of the Bi-based solar cells by creating high-quality BiI3 or MBI thin films. 相似文献
100.
《Ceramics International》2022,48(5):5876-5891
Hybrid lead halide perovskite solar cells (PSCs) have experienced a rapid development in the past decade and a certified efficiency up to 25.5% has been achieved. However, the presence of toxic lead component and the inherent poor thermal stability of the organic cations in the hybrid lead halide perovskites obstruct the commercial applications of their corresponding photovoltaic devices. Therefore, fabricating high-efficient all-inorganic lead-free PSCs is a promising direction. This review summarizes the related research progress, which mainly focuses on the structural and optoelectronic properties of inorganic lead-free perovskites and devices. In particular, the strategies for improving the properties and stability of Cs–Sn perovskites, as well as enhancing the photovoltaic performance of the corresponding devices are highlighted. An outlook of challenges and future directions regarding to all-inorganic lead-free PSCs are also proposed. 相似文献