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A large adiabatic temperature change along with a wide operating temperature region is usually required for the electrocaloric materials to fulfill their refrigeration function. In general, doping foreign ions into BaTiO3 is the frequently utilized strategy in order to obtain excellent electrocaloric materials for the practical application. In the current paper, BaTiO3 lead‐free ferroelectric ceramics were doped by Ca2+ and Sn4+ simultaneously in order to generate a coexistence state at room temperature, where ferroelectric domains and nanodomains exit. As a result, a large polarization and a wide operating temperature range were finally induced. It is found that Ba0.9Ca0.1Ti0.85Sn0.15O3 has a maximum adiabatic temperature change of 0.85 K and an excellent working temperature region (65 K, ∆T > 90% Tmax) was achieved under an electric field of 50 kV/cm. The above phenomenon indicates that the modified BaTiO3 ceramics can be a good potential electrocaloric material in the state of cross‐existence of ferroelectric domains and nanodomains. [ABSTRACT FROM AUTHOR]

Electrowetting is a widely used and effective method to tune the wettability of ionic liquids at solid-liquid interfaces, but it usually requires an external electric field. Here, we proposed a strategy for conveniently tuning ionic liquid wettability by adopting ferroelectric LiNbO3 single crystals as functional substrates. A heating pretreatment process was applied to modulate the surface charge characteristics of LiNbO3 substrates, leading to an improved wettability of [EMIM][BF4] and [EMIM][NTf2] on the LiNbO3 substrates with both positively poled (+Z) and negatively poled (−Z) surfaces. This work may be of great interest in the field of ferroelectric-based microelectronics. [ABSTRACT FROM AUTHOR]

As a typical cell structure, the cylindrical ferroelectric capacitor (CFE-cap) has been widely used in 3-D ferroelectric memories. Unlike planar ferroelectric capacitor, the CFE-cap has nonuniform electric field and polarization distribution. In this article, we investigate the impacts of the radius on the capacitance, field distribution, electrode charge densities of both the isotropic and anisotropic CFE-caps. As the inner radius increases, the CFE-cap behaves more like the planar capacitor with the same ferroelectric thickness. The results indicate that CFE-cap has an additional knob of inner radius Rin to tune its ferroelectric and electric characteristics. We have considered two kinds of CFE-caps, isotropic and anisotropic CFE-caps. The former is found to have stronger ferroelectric response than the latter, such as higher normalized capacitance and larger polarization. [ABSTRACT FROM AUTHOR]

[Display omitted] • Unique popcorn-like nanosphere structure endows abundant active sites. • DFT theoretical calculation reveal the transfer pathway of charges. • Hierarchical tandem heterojunctions promote the separation of carriers. • The H 2 production efficiency is 50 times higher than the unmodified material. • It offers a new method for green energy conversion and hydrogen energy separation. Heterojunction engineering is widely recognized as one of the most effective strategies for enhancing photocatalytic performance and suppressing photocorrosion by promoting efficient carrier separation and transfer. In this work, popcorn-like ZnCdS-MoS 2 @Co 3 O 4 nanospheres with large specific surface areas and hierarchical tandem heterojunctions were synthesized via one-pot in-situ self-assembly combined with hole-driven photodeposition. Based on the highly uniform dispersion of MoS 2 as an electron collector in the system and precise deposition of Co 3 O 4 as a photogenerated hole collector driven by photogenerated carriers at the hole enrichment position, it can efficiently catalyze the photocatalytic hydrogen evolution in water. Compared to ZnCdS, the optimized ZCS-M@0.5C exhibits a 50-fold increase in visible-light-driven hydrogen evolution efficiency, achieving 18.73 mmol·h−1·g−1 and maintaining stability after a 20-hour cycle test. Additionally, the apparent quantum yield reaches a remarkable 10.11% at 420 nm. Experimental characterization tests and differential charge density analysis have confirmed the efficient ability of Pt-like MoS 2 to induce electron separation and transportation, while p-type semiconductor Co 3 O 4 accumulates holes through the p-n junction. Both theoretical and experimental evidence show that the incorporation of dual-internal electric fields facilitates bi-directional charge separation and rapid transfer. The photocatalytic performance is improved through a synergistic effect involving hierarchical tandem heterojunctions. This work presents a novel approach to fabricating highly efficient photocatalysts with multi-heterojunctions through synergistic effects. [ABSTRACT FROM AUTHOR]

Suppressing charge recombination and improving carrier transport are key challenges for the enhancement of photocatalytic activity of heterostructured photocatalysts. Here, we report a ferroelectric polarization-enhanced photocatalysis on the basis of BaTiO3-TiO2 core-shell heterostructures synthesized via a hydrothermal process. With an optimal weight ratio of BaTiO3 to TiO2, the heterostructures exhibited the maximum photocatalytic performance of 1.8 times higher than pure TiO2 nanoparticles. The enhanced photocatalytic activity is attributed to the promotion of charge separation and transport based on the internal electric field originating from the spontaneous polarization of ferroelectric BaTiO3. High stability of polarization-enhanced photocatalysis is also confirmed from the BaTiO3-TiO2 core-shell heterostructures. This study provides evidence that ferroelectric polarization holds great promise for improving the performance of heterostructured photocatalysts. [ABSTRACT FROM AUTHOR]

Lead-free bulk ceramics for advanced pulse power capacitors possess low recoverable energy storage density (W rec) under low electric field. Sodium bismuth titanate (Bi 0.5 Na 0.5 TiO 3 , BNT)-based ferroelectrics have attracted great attention due to their large maximum polarization (P m) and high power density. The BNT-ST: xAlN ceramics are designed and fabricated to get high W rec and large P m under low electric field simultaneously. An excellent large P m (49.04 μC/cm2) and W rec (2.07 J/cm3) under low electric field (160 kV/cm) are acquired in BNT-ST: 0.1 wt% AlN. The domain structure evolution and polarization switching are investigated systematically using piezoresponse force microscopy (PFM). The introduction of AlN promotes the formation of thermal conductive network and the crystallization of ceramics, thus improving thermal stability and increasing P m significantly. The higher density of domain walls and the larger negative built-in voltage may be beneficial to increase breakdown field strength (E b), while the more 180° domains induce by electric field and the better domain switching behavior contribute to a significant increase in P m. The enhanced E b and super high P m are favorable for obtaining high W rec under low electric field which will boost the application of BNT-based ferroelectrics in advanced pulse power capacitors. [ABSTRACT FROM AUTHOR]

• Ag nanoparticles are anchored onto CuS sub-micron flowers to form composites. • The CuS@Ag electrodes exhibit enhanced charge storage property. • The decoration of Ag nanoparticles increases the electrical conductivity. • The generated electric field at the CuS/Ag interface accelerates the charge transfer. [Display omitted] In this reported work, Ag nanoparticles (NPs) decorated CuS sub-micron flowers are synthesized using a facile, solvothermal reaction coupled with a silver mirror reaction. The experimental results and theoretical calculations reveal that decorating the CuS with Ag NPs increases its intrinsic electrical conductivity and generates an electric field at the interface between Ag and CuS. These effects promote the efficient utilization of active materials and accelerate the interface charge transfer and electrochemical reaction kinetics. Consequently, the maximum specific capacity of the prepared CuS@Ag electrodes is found to be as high as 702 C g−1 at 2 A g−1, which is about 5 times greater than the pure CuS electrode. In addition, the capacity value is 400 C g−1 at 20 A g−1 and it exhibits 93% retention of the initial capacity after 5000 cycles at 10 A g−1. Moreover, a hybrid supercapacitor (HSC) device is assembled employing the CuS@Ag electrode as the positive electrode, which delivers an energy density of 51.1 Wh kg−1 at a power density of 798 W kg−1. These results demonstrate the promising potential of the fabricated CuS@Ag composites for further application in HSCs. [ABSTRACT FROM AUTHOR]

The mechanism of excited state proton transfer (ESPT) has been widely investigated in various fields, owing to its fundamental role in many systems. The ability to regulate the ESPT process has enabled the range of its applications to be greatly expanded, and the corresponding investigative work has become increasingly sophisticated. In particular, the unmeasurable quantities at a molecular level are of great interest. As modulation technology forms the foundation of many applications of ESPT, its development is worthy of further exploration and discussion. In this article, we summarize recent approaches to ESPT regulation, including the use of solvent polarity, electric fields, and solvent medium. We also consider the mechanisms of ESPT and related applications, and discuss the debate over whether a stepwise or concerted process occurs in systems of excited state double proton transfer. Finally, we summarize the challenges of ESPT research and present some ideas that may guide future progress. In this perspective article, we briefly review the mechanism of ESPT and make a partial summary of recent approaches to the regulation of ESPT. Several primary factors in ESPT modulation are considered, including the use of solvent polarity, electric fields, solvent medium, etc. The facilitation effect of solvent molecules on multiple proton transfer along reaction channels formed by hydrogen bond wires is also discussed. Finally, the challenges of ESPT are summarized, and some ideas are presented which may be used to make progress in the future. [ABSTRACT FROM AUTHOR]