Search

Dielectric capacitors prepared by antiferroelectric (AFE) materials have the advantages of large power density and fast discharge ability. It has been a focus on the improvement of the recoverable energy density (Wrec) and discharge energy–density (Wdis) in the AFE ceramics. To address the above issue, optimizing the proportion of components is proposed for enhancing ceramic antiferroelectricity, ultimately improving the breakdown strength (Eb) and Wrec. In this work, an ultrahigh Wrec (14.3 J/cm3) with an excellent energy efficiency (η) of 81.1% is obtained in (Pb0.96Sr0.02La0.02)(Hf0.9Sn0.1)O3 AFE ceramic at electric field of 490 kV/cm, which is the maximum value reported in lead-based AFE ceramics fabricated by the conventional solid-state reaction method so far. The multistage phase transition induced by the electric field is observed in the polarization–electric field (P–E) hysteresis loops. Furthermore, an outstanding power density (PD) of 335 MW/cm3 and an excellent Wdis of 8.97 J/cm3 with a rapid discharge speed (102 ns) are obtained at electric field of 390 kV/cm. In addition, (Pb0.96Sr0.02La0.02)(Hf0.9Sn0.1)O3 ceramics also possess an excellent thermal and frequency stability. These exceptional properties indicate that (Pb0.98−xSrxLa0.02)(Hf0.9Sn0.1)O3 ceramics are a potential candidate for pulsed power devices and power electronic devices. [ABSTRACT FROM AUTHOR]

Ferroelectric materials hold immense potential for diverse applications in sensors, actuators, memory storage, and microelectronics. The discovery of two-dimensional (2D) ferroelectrics, particularly ultrathin compounds with stable crystal structure and room-temperature ferroelectricity, has led to significant advancements in the field. However, challenges such as depolarization effects, low Curie temperature, and high energy barriers for polarization reversal remain in the development of 2D ferroelectrics with high performance. In this review, recent progress in the discovery and design of 2D ferroelectric materials is discussed, focusing on their properties, underlying mechanisms, and applications. Based on the work discussed in this review, we look ahead to theoretical prediction for 2D ferroelectric materials and their potential applications, such as the application in nonlinear optics. The progress in theoretical and experimental research could lead to the discovery and design of next-generation nanoelectronic and optoelectronic devices, facilitating the applications of 2D ferroelectric materials in emerging advanced technologies. [ABSTRACT FROM AUTHOR]

Highly precise and efficient characterization of thermophysical parameters associated with martensitic transformation (MT) in shape memory alloys (SMA) is challenging based on conventional calorimetry methods. Moreover, existing methods for evaluating the elastocaloric effect of SMA typically require a series of tests and calculations. In addition, the present method cannot evaluate the nonreversible part during MT. This work proposed a technique rarely mentioned in previous studies on martensitic transformation of metals and alloys, i.e., utilizing the modulated differential scanning calorimetry (MDSC) to superimpose a sinusoidal signal over an underlying DSC ramp. By adjusting appropriate measurement parameters, the reversible and nonreversible parts of thermal events during MT of SMAs were revealed. Furthermore, a series of thermal parameters useful for the study of MT can be obtained by this method and thus may provide a perspective for studying the MT process. Based on MDSC technique, we took Ni-Mn-Sn-(Cu) alloys, a kind of ferromagnetic shape memory alloy, as an example to demonstrate the study of the MT process as well as the elastocaloric effect. From the perspective of energy dissipation, we analyzed the intrinsic relationship between nonreversible component and thermal hysteresis in the MT process. Conventional DSC test and experimental results on the adiabatic temperature change (ΔTad) were also provided to verify the MDSC prediction results. [ABSTRACT FROM AUTHOR]

Organic–inorganic halide perovskite have shown great promise for photovoltaic applications due to their unprecedented optoelectronic properties and low manufacturing cost. However, the commercialization of this emerging technology is hampered by its thermal instability and intrinsic Pb‐toxicity. Here, we report first‐principles investigations on stability and optoelectronic properties of a series of all‐inorganic lead‐free metal halide perovskite‐like materials AMX4 (A = Cs, Ag, and Rb; M = In, Sb, and Bi; X = Cl, Br, and I). Our calculations show that AgSbI4 and AgBiI4 have direct bandgaps of 1.63 and 1.44 eV, which possess strong interband optical absorption (≈105 cm−1). Based on these favorable properties, we also simulated the AgSbI4‐ and AgBiI4‐based thin film solar cells with the SCAPS‐1D code and achieve high PCE of 24.19% and 26.70%, respectively. These results reveal that the AMX4 perovskite‐like materials could serve as potential alternatives to Pb‐based halide perovskites in photovoltaic devices. [ABSTRACT FROM AUTHOR]