Aim: Zinc oxide (ZnO) is an n-type semiconductor with a wide bandgap, excellent electron mobility, and stable chemical characteristics, making it potentially applicable in the field of gas sensing. However, conventional ZnO-based gas sensors face challenges such as high operating temperatures and low sensitivity.

Methods: In this paper, we first synthesized ZIF-8 with a rhombic dodecahedron structure using a room-temperature chemical precipitation method. By doping ZIF-8 with cobalt (Co) and exchanging gold ions, followed by calcination in air, we obtained a metal-organic framework (MOF) derived porous Au@Co-ZnO nanostructure.

Results: This nanostructure retained the large specific surface area and porous characteristics of ZIF-8, while its gas sensing performance was significantly enhanced compared to the pure MOF-derived ZnO nanostructure, due to Co doping and gold nanoparticle modification. At an ethanol concentration of 100 ppm, the Au@Co-ZnO sample demonstrated its best performance at 140 °C, with a response value of 205.3. This result was 28.9 times higher compared to the pure ZnO sample, which showed a response value of 7.1 under identical conditions. Additionally, the optimal operating temperature was 40 °C lower than that of the pure ZnO sample (180 °C). Furthermore, the Au@Co-ZnO samples demonstrated good stability and selectivity for ethanol gas.

Conclusion: The proposed MOF-derived porous Au@Co-ZnO nanostructures not only advance the application of MOF-derived materials in gas detection but also offer a novel approach for boosting the gas-sensing performance of other metal oxide materials.

The discovery of cage hydrides (Y,Ca)H₆, (La,Ce)H₉, and (La,Y)H₁₀ indicates the appeal of ternary hydrides as contenders for high-temperature superconductors. Herein, we systematically studied a La-Sr-H system and predicted interesting stable and metastable hydrides at 200 GPa by first-principles calculations. The results revealed that LaSrH₂₁ has a high superconducting transition temperature (T_c) of 211 K at 200 GPa, mainly attributed to its unique H₁₂ rings. LaSrH₁₂, LaSr₂H₁₈, and LaSr₃H₂₄ contain distorted H₂₄ cages and exhibit high T_c values of 160, 167, and 169 K, respectively. Notably, LaSrH₁₂ maintained dynamic stability down to 30 GPa, which is extremely low for H₂₄ cage hydrides. In addition, the T_cs of LaSrH₁₂ increased at a rate of 0.43 K/GPa with the increase in pressure. Further analysis revealed that the positive pressure-dependent T_c was mainly due to the softening of the low-frequency phonon modes and Lifshitz transition. Our work will guide the study of ternary rare- and alkaline-earth hydrides.

Quaternary chalcogenides have garnered considerable interest within the field of thermoelectric due to their intrinsic low thermal conductivity, wide bandgap and high element enrichment advantages. In this work, the thermoelectric performance of Cu₂MnSnSe₄ was enhanced by co-optimizing the carrier concentration and lattice thermal conductivity through self-doping with Cu and doping with Te. A series of Cu₂MnSnSe₄ and Cu_2.1Mn_0.9SnSe_4-xTe_x (x = 0, 0.01, 0.05, 0.10) samples were prepared by ball-milling and hot-pressing methods. The carrier concentration of the samples was significantly increased after Cu self-doping, leading to optimized electrical transport performance. The notable reduction in lattice thermal conductivity was attributed to the scattering effect caused by Te substitution-induced point defects. At 673 K, the lattice thermal conductivity of the Cu_2.1Mn_0.9SnSe_3.9Te_0.1 sample obtained the lowest value of 0.62 W m^-1K^-1. Finally, it achieved a maximum zT ~ 0.5 at 673 K in the Cu_2.1Mn_0.9SnSe_3.9Te_0.1 sample, roughly twice that of the Cu₂MnSnSe₄ sample.

The deformation mechanism of body-centered cubic (bcc) structured high-entropy alloys (HEAs) has been the subject of considerable research interest. Although a considerable number of studies have been conducted, the majority have focused on relatively large HEAs. As the size of bcc structured HEAs decreases to the nanometer scale, the manner in which they accommodate plastic deformation remains unclear. In this study, we employed molecular dynamics simulations to investigate the mechanical behavior of HfNbTaTiZr HEA nanowires during tensile loading and unloading. The results demonstrated that the plastic deformation of HEA nanowires was governed by a transition from the bcc phase to the hexagonal close-packed (hcp) phase. This contrasts with previous studies that attributed the deformation to screw dislocation activities. The bcc-hcp phase transition was found to occur via Bain strain, which involves lattice distortion and atomic rearrangement, ultimately resulting in the formation of the hcp phase. Notably, this bcc-hcp phase transition was reversible upon unloading, demonstrating a shape memory effect. This phase transition and its recoverable nature at room temperature were rarely reported in bcc structured HEAs. Our findings provide a comprehensive understanding of the deformation mechanisms of nano-sized HEAs.

Responsive materials exhibit intelligence through their intrinsic ability to autonomously sense and respond to external stimuli. These materials have the potential to form robotic swarms characterized by high flexibility, robust scalability, and fault tolerance. Among various responsive materials, hydrogels and liquid crystalline polymers are particularly advantageous due to their capability for reversible morphological transformations in response to external stimuli, including light, heat, electric field, and magnetic field. While numerous reviews have summarized magnetic swarm robotics, a comprehensive analysis of swarm aggregation behaviors in hydrogel- and liquid crystal-based polymer systems remains lacking. This review addresses this gap by examining (sub)millimeter-scale swarm robots, the fundamental mechanical properties of hydrogels and liquid crystalline polymers following aggregation and assembly, and the respective advantages and limitations of these materials in swarm robotics. Additionally, future research directions in this emerging field are discussed.

The Pressure-assisted crystallization (PAC) technique has evolved alongside the development of metal halide perovskite materials, effectively harnessing the soft lattice characteristics of perovskites and integrating with thermal processing methods to enable the transformation of perovskite materials from fine grains into quasi-single crystals. This technique has led to significant improvements in the performance of perovskite functional devices. In recent years, a wealth of research on the PAC technique has emerged, and this paper provides a comprehensive review of these studies. The review systematically explores the role of the PAC process in perovskite materials from three key aspects: the mechanism of PAC, the effect of PAC, and the application of PAC in devices. It highlights how pressure significantly enhances the quality of perovskite films and wafers, as well as the performance of related devices, by promoting grain growth, merging grain boundaries, and eliminating voids. Finally, the paper assesses the challenges faced by PAC techniques and offers a forward-looking perspective on their future development.

Ferroelectric materials based on (Bi_0.5Na_0.5)TiO₃ are well-known for their outstanding chemical stability and exceptional electrical properties, particularly their large electrostrain response under applied electric fields, positioning them as promising candidates for precision actuator applications. In this study, we investigate the electrical and structural responses of lead-free (Bi_0.38Na_0.38Sr_0.24)Ti_1-x(Fe_0.5Nb_0.5)_xO₃ (BNST-xFN) ferroelectric ceramics under the combined effects of temperature and electric field. Using in-situ electric field and variable-temperature Raman spectroscopy, piezoelectric force microscopy, and comprehensive dielectric and ferroelectric property evaluations, we explore the evolution of structural transformations, polarization behavior, and macroscopic property changes in ceramics with different initial phase structures under thermal and electrical stimuli. Notably, the BNST-0.01FN composition, located near the boundary between the non-ergodic relaxor and ergodic relaxor phases, exhibits a remarkable room-temperature electrostrain of 0.37%, driven by a reversible electric field-induced nonpolar-to-polar phase transition. Upon heating, as the BNST ceramic approaches the phase boundary, a prominent electrostrain (~0.38%) is observed near the temperature of the ferroelectric-to-relaxor phase transition (T_FR, ~60 °C) under the electric field. This study combines in-situ microstructural analysis with macroscopic ferroelectric characterization, providing a deeper understanding of the dynamic coupling between microscopic fields and macroscopic electrical properties, and offering valuable insights for the design of high-performance lead-free ferroelectric ceramics.

Fluorine-containing poly(p-phenylene) (CityU-42) films on zinc surfaces were directly synthesized using a cathodic dehalogenation C-C coupling strategy. The as-prepared polymers can effectively protect the zinc substrate in aqueous zinc-ion batteries. Because CityU-42 is rich in the electronegative fluorine group, it can attract the uniform deposition and rapid diffusion of Zn²⁺ on the surface of the anode. Moreover, a large number of benzene rings provide certain mechanical strength, enabling the protective layer to inhibit the growth of dendrites. As a result, the symmetric Zn Zn cell used CityU-42@Zn can stably cycle for over 1,900 h under 5 mA cm^-2 and 1 mAh cm^-2, while the CityU-42@Zn V₂O₅ full cells maintain high capacity retention after 800 cycles at 5 A g^-1. The results highlight the potential of synthesizing conjugated polymers using cathodic dehalogenation technology, paving the way for further advancement in the field of energy storage technology.

Aim: Aqueous zinc (Zn)-ion batteries have gained recognition as a promising energy storage solution due to their abundant zinc resources, cost-effectiveness, high energy density, and inherent safety. However, their practical application is significantly limited by issues such as dendrite formation and parasitic side reactions, which undermine the stability, efficiency, and longevity of Zn anodes. Methods: In this study, we present a novel approach by introducing a nanocrystalline nickel-tungsten (Ni-W) coating onto Zn anodes via electrodeposition. This coating acts as a functional interface, regulating Zn dissolution and deposition, suppressing dendrite growth, and minimizing side reactions. Additionally, W enhances Zn²⁺ ion adsorption, reduces nucleation energy barriers, and promotes uniform Zn growth along the Zn (002) crystallographic plane. Results: The compact morphology of the Ni-W layer further serves as a protective barrier, improving electrode stability during extended cycling. The Ni-0.1W@Zn anode demonstrates outstanding electrochemical performance, achieving over 2,000 h of stable operation at 1 mA cm^-2 with a Coulombic efficiency of 98%. In full cell configurations paired with Ni-0.1W@Zn||V₂O₅, the system retains 81% of its capacity after 1,500 cycles at 1 A g^-1. Conclusion: These findings highlight the transformative potential of the Ni-W coating as a scalable and sustainable solution to address the fundamental limitations of Zn anodes, paving the way for advanced and durable energy storage technologies critical to renewable energy systems.

Advanced electronic systems and innovative pulsed power applications are driving the rapid development of high-energy-storage density and high-efficiency capacitors. In the present study, we have prepared SrBa_3.5Sm_0.5R_0.5Nb_9.5O₃₀ (R = Mn, Ti, Sn, Hf) (henceforth referred to as SBSRN) ceramics by solid-phase synthesis, using a site engineering strategy that utilizes tetravalent ions for the substitution of Nb⁵⁺ at the B-site of tetragonal phase tungsten bronzes. SBSRN ceramics benefit from site engineering strategies to enhance overall energy storage performance. As a result, they achieve a substantial energy storage density of 4.31 J·cm^-3 and an impressive efficiency of 91.3% when subjected to an electric field of 340 kV·cm^-1, and show excellent stability in ferroelectric performances with variable temperature and frequency. In addition, these ceramics have a large discharge energy density of 2.68 J·cm^-3 and a fast discharge time of 62 ns in charge/discharge tests, along with a current density of 619.96 Acm^-2 and a power density of 65.1 MWcm^-3. In summary, this research offers a promising method for developing energy storage materials that hold potential for innovative applications in pulsed power components.

Perovskite layer structured (PLS) oxides exhibit some novel physical properties, such as ultrahigh-temperature piezoelectricity, semiconductivity, and oxygen ionic transport. However, synthesizing 5-layer PLS oxides, such as Sr₅Nb₅O₁₇ ceramics, using traditional solid-state reaction methods is challenging due to their low phase stability. In this study, we propose a new strategy to construct a 5-layer structure from a 4-layer structure. Specifically, Ga-doped Sr₅Nb_4.444Ga_0.556O_16.944 (5-SNGO), an iso-structural material to Sr₅Nb₅O₁₇, was synthesized via a solid-phase reaction. The original design involved co-doping Ga and Mo at the Nb site of the 4-layer parent material Sr₂Nb₂O₇ (4-SNO). However, it was found that only Ga was successfully incorporated into the structure, while Mo remained as SrMoO₄, which was subsequently removed by washing with dilute sulfuric acid. X-ray diffraction, transmission electron microscopy, and second-harmonic generation analysis confirmed that the synthesized 5-SNGO ceramic exhibits a 5-layer structure with a noncentrosymmetric space group. The material demonstrated a frequency-independent dielectric permittivity of 60 above 1 kHz. Impedance spectroscopy revealed a very high resistivity of 1.95 × 10⁵ Ω·cm at 900 °C, along with Debye-like dielectric relaxation exhibiting thermal activation behavior. This study presents a novel synthesis approach for constructing 5-layer PLS oxides from a 4-layer structure and provides insights into their structural evolution and electrical properties.

The diatomic nanozymes (DANs) represent a class of nanomaterials containing dual metals as active centers with enzyme-like activity inspired by natural enzymes. They hold unique catalytic properties caused by their dual-atom structure, which have attracted significant attention. The catalytic mechanism of DANs may involve synergistic interactions between neighboring metal atoms and the regulation of electron arrangement near the active center, enhancing catalytic activity and specificity. The excellent catalytic activity and exceptional stability make DANs promising candidates for developing sensitive biosensors capable of precisely detecting disease markers. Furthermore, DANs show great promise as antitumor therapeutic agents, offering enhanced efficacy while minimizing side effects. This review outlines the catalytic mechanism and biomedical applications of DANs. The discussion section highlights the challenges and prospects in the development of DANs, offering insights for future research endeavors in this field.

Ge-Sb-Sn/Se with a superlattice-like structure (SLL) is a promising material candidate for multi-level phase change photonics memory technology. However, its multi-stage phase transition process has not been elucidated so far due to the limitations of traditional research approaches. The most critical issue is to efficiently construct its composition-process-structure-property multi-parameter coupled constitutive relationship. In this work, we develop a high-throughput approach to systematically study the multi-level phase transition mechanisms of Ge-Sb-Sn/Se SLL combinatorial thin films. For the Ge-Sb-Sn system, phase evolution is observed from trigonal to hexagonal/tetrahedral structures. In contrast, the Ge-Sb-Se system behaves differently. We further examine the optical properties of the Ge-Sb-Sn/Se SLL combinatorial thin films. The results identify the GeSbSn₃ SLL thin film as a standout from the Ge-Sb-Sn ternary system under Sb→Sn→Ge deposition sequence, with a figure of merit (FOM) greater than 0.4 and high thermal stability. The present study serves as a foundation for further exploration of the Ge-Sb-based quaternary system and accelerates the application of advanced phase change materials (PCMs) in the big data era.

Metal halide perovskites are promising light emitters due to their tunable and highly pure emission color in visible light. However, achieving deep blue emission remains a major challenge due to low stability and intrinsic defects. Traditional methods for synthesizing blue-emitting colloidal perovskite nanocrystals (PNCs) involve organic ammonium engineering and halide engineering, which often suffer from problems such as ion migration and color instability. In this study, we demonstrate a novel central metal engineering approach that achieves deep blue emission with a wavelength of 435.8 nm from pure bromide-based PNCs at room temperature. To synthesize deep blue-emitting pure-bromide-based PNCs, we incorporate manganese bromide (MnBr₂) to the formamidinium-guanidinium lead bromide (FA_0.9GA_0.1PbBr₃) PNCs. Mn²⁺ suppresses the growth of FA_0.9GA_0.1PbBr₃ crystals during the synthesis, resulting in decreases in both particle size and dimensionality and deep blue emission by the quantum confinement effect. The emission wavelength of pure-bromide-based PNCs is controlled by varying the amount of MnBr₂. This study provides an effective and simple method for achieving deep blue emission from pure bromide-based PNCs, offering significant advantages for display technologies such as light-emitting diodes.

Tissue damage poses a significant burden on patients’ daily lives and has long driven the search for effective clinical treatments. Recent decades have witnessed the development of smart biomedical materials for satisfying specific requirements such as irregular shapes and dynamic microenvironments at defective sites. Stimuli-responsive polymeric films are well-positioned to play a considerable role in the exploitation of next-generation smart biomaterials for both soft and hard tissue regeneration. These polymeric films can be fabricated through diverse approaches and engineered with versatile structures and properties. Furthermore, responsive to stimuli such as temperature, water, and light, these films exhibit well-designed functions such as shape adaption, controlled drug release, and cell adhesion in vivo, effectively improving tissue regeneration. In this work, we review the recent advancements in stimuli-responsive biomedical polymeric films, beginning with the introduction of their fabrication methods. Subsequently, the stimuli-responsive mechanisms of the films are discussed and scrutinized in terms of structure and property variations. An overview of recent applications of stimuli-responsive films in tissue regeneration, including skin, cardiovascular, nerve, and bone regeneration, is provided. Finally, we further discuss the benefits and limitations of these smart films in practical applications, proposing our expectations and perspectives on future advancements of stimuli-responsive polymeric films.

Photocatalysis plays a pivotal role in sustainable technology, driving pollutant degradation and energy conversion through solar-driven chemical reactions. However, conventional photocatalysts are limited by their structural tunability, hindering their adaptability to evolving photocatalytic applications. This underscores the urgent need for innovative approaches to overcome these challenges. Metal-organic frameworks (MOFs), with their tunable structures, offer a promising solution by overcoming these limitations. Here, we demonstrate a comprehensive overview of the structural regulation strategies in MOFs, emphasizing their evolution across multiple scales to enhance photocatalytic performance. This review begins by detailing the photoelectric and structural characteristics of MOFs and their development in structural regulation strategies for photocatalytic effectiveness. An in-depth analysis is undertaken into structural regulation strategies across multiple scales - macroscale, mesoscale, atomic-scale, and electronic-scale. The synergistic interactions among these levels are further explored, revealing their collective contribution to improved photocatalytic efficiency. These insights emphasize that the adaptable design strategies of MOFs serve as promising pathways for advancements in photocatalyst engineering. Finally, we examine the current photocatalytic applications of tunable structures in MOFs and provide perspectives on future challenges and advancements in this field. This review offers critical insights into MOF structural regulation, highlighting its role in driving innovations in photocatalyst design and expanding photocatalytic technologies.

Transmission electron microscopy (TEM) is a cutting-edge characterization technique renowned for its ability to achieve atomic resolution. Owing to its exceptional capacity for microscopic characterization, TEM has emerged as an essential and powerful tool in the realms of structural characterization and chemical analysis. Its applications span a diverse array of fields, including materials science, chemistry, and biology, offering unprecedented insights into the fundamental structure understanding of various substances. The capability of TEM to facilitate direct observation of small molecules holds significant promise for advancing our understanding of molecular structures, host-guest interactions, and their dynamic behaviors. However, a couple of challenges hide this potential. Notably, issues such as electron beam irradiation can damage small molecules, while low contrast of small molecules compared to the background presents considerable obstacles during imaging. These factors necessitate the continued development of innovative techniques that enhance the efficacy of TEM. In this review, we offer a brief introduction to advanced TEM techniques aimed at directly imaging small molecules, including cryo-electron microscopy, low electron dose imaging, and in situ TEM techniques. We review recent advancements in atomic-resolution TEM studies involving small molecules, highlighting significant findings and methodological improvements that have emerged in the field. In addition, we provide an outlook on the future trajectory of TEM studies on small molecules, emphasizing the potential progress that could stimulate further scientific exploration in this realm.

Ferro/piezoelectric transparent materials with both excellent piezoelectricity and transparency are of great interest for irreplaceable applications in numerous fields such as photoacoustic imaging and transparent robots. Nevertheless, developing a lead-free ferroelectric ceramic that meets both distinct transparency and high piezoelectricity has always been challenging. Herein, the simple single Sm³⁺ doped KNN ferroelectric ceramics (xSm) are designed to improve transparency and achieve reasonable piezoelectricity. The results indicate that although the donor doping effect of Sm³⁺ significantly improves the transparency by mainly causing grain refinement and densification improvement, it also enhances the relaxor behavior of KNN ceramics and weakens the piezoelectricity. Despite this, with proper Sm doping, reasonable piezoelectricity can still be achieved in the xSm transparent ceramics without causing a significant decrease in Curie temperature. Ultimately, excellent comprehensive performance was achieved in the 1.0 Sm ceramic (T~65% at 900 nm, T_C~395 °C, d₃₃~65 pC/N), competitively in the KNN-based transparent ceramics. In force sensitivity testing, the 1.0 Sm ceramic also exhibits prominent force response electrical output characteristics, which is expected to be applied in smart windows that require real-time pressure detection. This work furnishes a methodology for the fabrication of KNN-based transparent piezoceramics, while contemporaneously recommending innovative perspectives for broadening their range of applications.

The phase-field method has become a powerful tool in materials science and engineering, providing a strong framework to understand phase transitions and microstructure evolution. By connecting atomic-scale phenomena to macroscopic behavior via mesoscale modeling, it has greatly enhanced our understanding of material processes. This paper presents micromagnetic microelastic phase-field modeling and explores recent applications of this approach in studying microstructural evolution and ultrasensitive magnetoelastic responses at phase boundaries in magnetoelastic functional materials, including magnetostrictive compounds and ferromagnetic shape memory alloys. The paper also discusses significant advances in phase-field modeling of magnetoelastic-electric coupling in multiferroic systems and magnetoelectric heterostructures. Finally, we identify key challenges and future directions for the phase-field method to advance the development of magnetoelastic functional materials.

Symmetry is a cornerstone of condensed matter physics, fundamentally shaping the behavior of electronic systems and inducing the emergence of novel phenomena. The Hall effect, a key concept in this field, demonstrates how symmetry breaking, particularly of time-reversal symmetry, influences electronic transport properties. Recently, the nonlinear Hall effect has extended this understanding by generating a transverse voltage that modulates at twice the frequency of the driving alternating current without breaking time-reversal symmetry. This effect is closely tied to the symmetry and quantum geometric properties of materials, offering a new approach to probing the Berry curvature and quantum metric. Here, we provide a review of the theoretical insights and experimental advancements in the nonlinear Hall effect, particularly focusing on its realization in two-dimensional materials. We discuss the challenges still ahead, look at potential applications for devices, and explore how these ideas might apply to other nonlinear transport phenomena. By elucidating these aspects, this review aims to advance the understanding of nonlinear transport effects and their broader implications for future technologies.

Color converters are indispensable components in photoluminescence white-light devices. As optical wireless communication (OWC) systems leveraging solid-state lighting (SSL) continue to evolve, the development of next-generation color conversion materials has become a pressing priority to meet the stringent requirements for both high-quality illumination and high-speed data transmission. Halide perovskite quantum dots (PQDs) have emerged as promising candidates due to their exceptional color purity, high photoluminescence quantum yield, and fast response time. However, the commercial viability of PQD-based SSL-OWC systems is persistently impeded by several challenges, such as insufficient modulation bandwidth, inadequate long-term stability, and reliance on toxic elements. This review delves into the applications of PQD-based color converters within the realm of OWC. Initially, we conduct a theoretical investigation into the factors that influence the modulation bandwidth and transmission rate of PQD-based systems, revealing the significance of reducing PQD particle sizes in enhancing these parameters. Subsequently, we provide a comprehensive overview of optimization strategies across four critical aspects: the selection of excitation sources, the refinement of PQD structure and encapsulation, the deployment of modulation schemes and multiplexing techniques, and the advancement of lead-free PQD alternatives. Finally, we summarize different types of PQD-based OWC applications, including white-light-based visible light communication transmitters, underwater wireless optical communication transmitters, and color-converting photodetectors. These applications underscore the dual functionality of PQD layers in both illumination and the facilitation of wavelength-tunable OWC.

High-performance perovskite relaxor-PbTiO₃ (relaxor-PT) piezoelectric single crystals (SCs) fabricated by the melt-growth Bridgeman method have been widely used in medical ultrasound imaging devices as probes and in high-performance underwater equipment since around 2,000. To improve the piezoelectric properties of these SCs, the use of alternating-current poling (ACP) instead of conventional DC poling has been widely adopted since 2018. Macro- and microstructural observations by scanning electron microscopy (SEM) are the best way to easily confirm the relationship between electrical properties and macro- and microstructure. After optimal ACP, fine 109° domain layers of 0.5 to several µm parallel to the electrodes have been obtained, contributing to 10%-100% improvement in dielectric constant and piezoelectric constant. Relaxor-PT SCs fabricated by the solid state crystal growth method with self-poring, excellent composition uniformity and machinability, high piezoelectric performance, and the low acoustic impedance due to the inclusion of spherical micropores in the SCs are also discussed.

Tin halide perovskite solar cells (THPSCs) are an eco-friendly alternative to lead halide perovskite solar cells. However, defect formation hinders their commercialization. Specifically, the oxidation of Sn²⁺ to Sn⁴⁺ generates defects, which increase background current due to charge recombination and consequently degrade device performance. This review explores the use of two-dimensional (2D) materials and additives to enhance the performance and stability of THPSCs. 2D materials improve charge transport, passivate defects, induce vertical alignment, and enhance structural stability against moisture. Additives optimize film morphology and interface properties by promoting grain growth and reducing defect density. These approaches increase the power conversion efficiency of THPSCs by up to 15%, demonstrating their commercial potential. The synergistic effects of 2D materials and additives are analyzed, and critical strategies for their combined utilization are suggested to develop high-efficiency and stable THPSCs.

Resistive switching devices, particularly memristors, have attracted considerable interest due to their promising applications in neuromorphic computing and data storage. However, achieving high performance and reliability remains a significant challenge, especially in the optimization of their ferroelectric and switching properties. In this study, we report a substantial enhancement of both resistive switching and ferroelectric properties in NaNbO₃ (NNO)/PbTiO₃ (PTO) multilayers, facilitated by interfacial modifications of the electronic structure induced by defects and strain. The well-defined interfaces and strain gradients within the PTO layers lead to substantial alterations in local electronic properties, including Ti 3d orbital hybridization and oxygen octahedral tilting. These structural modifications enhance charge trapping dynamics, resulting in an ON/OFF ratio of 10⁴, compared with 10² in single-layer NNO films. The synergistic effects of enhanced polarization and electronic state modulation are shown to optimize both the ferroelectric and resistive switching behaviors, highlighting the pivotal role of interface engineering in achieving high-performance memristive devices.

Introducing pores is an effective approach for fabricating ultralow-ε_r ceramics; however, it is still unclear how the microstructures affect the microwave dielectric properties. In the present work, Al₂O₃-A and Al₂O₃-B porous ceramics were prepared by incomplete sintering at 1,000-1,650 °C and sintering at 1,650 °C with a porogen, respectively, so that the effects of porosity and ceramic connectivity can be clarified. The introduction of pores led to a significant decrease in ε_r, Qf, and |τ_f|, and Al₂O₃-B ceramic exhibits a slightly higher ε_r, a larger |τ_f|, and a much higher Qf value compared to the Al₂O₃-A counterpart with a similar relative density. For Al₂O₃-A, increasing the sintering temperature and relative density notably enhanced ceramic connectivity, while Al₂O₃-B's ceramic connectivity remained relatively insensitive to density variations. The improved ceramic connectivity in Al₂O₃-B enhanced the contribution of the ceramic phase to ε_r and τ_f, while also increased the Qf value by reducing ceramic-pore interfaces. Notably, Al₂O₃-B, with a low relative density of 48.31%, demonstrated a good combination of microwave dielectric properties, with ε_r = 4.16, Qf = 38,400 GHz, and τ_f = -44.3 ppm/°C. These findings reveal the strong dependence of microwave dielectric properties on ceramic connectivity in porous ceramics, and also inspire the development of ultralow-ε_r materials by regulating both the porosity and ceramic connectivity.