High-performance piezoelectric thin films are pivotal to microelectromechanical systems (MEMS), enabling diverse applications from precision sensing to mid-air haptic interfaces for virtual and augmented reality. However, achieving large piezoelectric responses on silicon remains challenging owing to lattice and thermal mismatches that generate substantial interfacial strain, leading to defect formation, mixed-phase growth, and poorly aligned ferroelectric domains. Herein, we present an interfacial strain-engineering epitaxial strategy that, using lead zirconate titanate (PZT) as an exemplar, enables deterministic control over thin-film growth and crystallographic orientation on silicon. By tailoring the interfacial strain of Pt bottom electrodes, we realize highly uniform (001)-PZT films exhibiting superior maximum polarization (Pmax similar to 111.55 & micro;C cm-2) with remnant polarization (Pr similar to 89.08 & micro;C cm-2), yielding an ultrahigh transverse piezoelectric coefficient (e 31) of 15.99 C & centerdot;m-2 that surpasses the performance of previously reported silicon-integrated ferroelectric systems. Furthermore, integration of these films into piezoelectric micromachined ultrasonic transducer (PMUT) arrays enables mid-air haptic feedback, demonstrating their functional viability for immersive tactile interfaces. This work establishes a universal pathway for strain-mediated epitaxy of piezoelectric thin films on silicon, paving the way toward high-performance tactile and MEMS technologies.

ABSTRACT Piezocatalysis, the direct conversion of mechanical energy into chemical reactivity, offers a promising route for sustainable pollutant removal and chemical synthesis. However, practical applications require materials that are able to simultaneously deliver high activity, stability, and ease of recycling. Here, we report a flexible micro‐nano‐engineered BaTiO 3 /PVDF@Ag composite film, whereby {111} BaTiO 3 single‐crystal microsheets are embedded in a poly (vinylidene fluoride) (PVDF) matrix and decorated with photo‐deposited Ag nanoparticles. This BaTiO 3 /PVDF@Ag composite microstructure design endows the optimal composite with outstanding piezocatalytic performance, including a Rhodamine B degradation rate constant of 0.24 min −1 , a hydrogen peroxide generation rate of 3520 µmol g −1 h −1 , and a CO 2 reduction rate of 535 µmol g −1 h −1 , while maintaining its activity over repeated cycles. Systematic structural, spectroscopic, and electrochemical characterization, together with theoretical simulations, reveal that the ferroelectric BaTiO 3 and electroactive β ‐phase PVDF enhance the local piezoelectric potential under mechanical stimulation, while the Ag nanoparticles act as efficient electron traps and catalytic sites. Interfacial polarization as resulting from the dielectric and conductivity mismatches between the composite components also reduces charge‐transfer resistance and thereby accelerates carrier separation and migration. These synergistic effects enable efficient formation of reactive oxygen species, thereby driving high H 2 O 2 yields and CO 2 reduction. The mechanically robust film can also be easily recovered and reused, demonstrating a viable route to green, high‐performance piezocatalysts for environmental applications.

Human activities and industrial processes produce abundant mechanical information. Detecting multidimensional mechanical information with a single pressure sensor is essential for highly integrated and reliable robotic tactile systems. However, existing pressure sensors generally lack 3D architectures design that can physically decouple complex mechanical inputs while maintaining low inter-mode crosstalk, as well as integrated manufacturing strategies for flexible 3D devices with spatially organized functional materials and electrodes. Here, we design a nature-inspired 3D piezoelectric sensor with an orthogonal architecture and inhomogeneous poling, enabling loading vector decomposition and electrical isolation for the simultaneous detection of pressure, shear, and contact location with low crosstalk. To realize this concept, we combine multimaterial 3D printing with a programmable localized electrostatic attraction approach, enabling the precise fabrication of flexible piezocomposite and electrodes in customizable 3D configurations. Finite element analysis (FEA) further guides geometric optimization to balance sensitivity and critical buckling load across different sensing modes. As a result, the multi-dimensional force sensor can detect slight impacts (approximate to 2.5 mN), operate as an ultralight anemometer for wind speed and direction measurements, and monitor robotic hand grasping under complex loading. Our approach provides a design paradigm and an integrated additive manufacturing method for extensive 3D functional electronics.

Dielectric capacitors are highly attractive for advanced power electronics owing to their ultrafast charge-discharge rate, high power density, and excellent reliability. Yet their application is hindered by the persistent trade-off between high recoverable energy density (W rec) and high efficiency (η) owing to the inherent coupling in single-phase dielectrics, where stronger polarization generally comes at the expense of higher hysteresis and limited breakdown strength. Here, we present a polar-nonpolar hierarchical phase architecture design in BaTiO3-BiMg0.5Ti0.5O3-based ceramics to overcome this limitation by modulating thermodynamic spinodal decomposition. The polar Ba-rich phase provides large maximum polarization, while the non-polar Cd-rich precipitation with a large bandgap acts as a high-resistivity barrier that isolates polar regions and enhances the breakdown field. Atomic-scale electron microscopy analysis reveals that the nanoscale polar regions (∼1-3 nm) with locally disordered configurations emerge in the ceramic, which lowers the energy barrier for domain switching and enables near-zero hysteresis losses. As a result, the optimized hierarchical composition achieves an ultrahigh efficiency of 92.8%, a high recoverable energy density of 9.7 J cm-3, an outstanding high figure of merit W F of 135 at 460 kV cm-1, along with excellent stability against temperature, frequency, and cycling, and fast discharge with a power density up to 185 MW L-1. This work demonstrates a robust design paradigm based on complementary dual-phase coexistence, offering fundamental insights and a practical pathway toward high-performance, lead-free dielectric capacitors.

Electrocaloric cooling, a solid-state refrigeration technology utilizing the electrocaloric effect (ECE), enables miniaturized cooling systems. However, its practical application is constrained by limited adiabatic temperature change (AT), restricted operating temperature span (Tspan), and the fact that peak performance typically occurs at elevated temperatures. To overcome this,(1-x)Ba0.76Sr0.24TiO3-xCa(Ti0.9Sn0.1)O3 (BST-CS) lead-free ferroelectric ceramics were synthesized via solid-state reaction, enhancing AT and Tspan through multi-ion doping. XRD and Raman spectroscopy confirmed tetragonal (T) and pseudo-cubic (PC) phase coexistence, with the PC phase increasing with doping. Temperature-dependent Raman and dielectric spectra revealed a tetragonal-cubic transition near the Curie temperature, contributing to the ECE. The optimized composition (x = 0.14) achieved AT = 1.74 K and Tspan= 52 K (40-90 degrees C, AT >= 80 % of ATmax) under 50 kV & sdot;cm-1. Phase coexistence lowers polarization barriers, while grain refinement improves breakdown strength. This work advances eco-friendly microelectronics cooling by balancing performance and practicality.

Lead zirconate titanate (PZT) thin films are key materials for MEMS devices. However, simultaneously achieving high breakdown strength and large polarization remains challenging. Herein, PbZr0.20Ti0.80O3 (PZ0.20T0.80) thin films with high breakdown strength and PbZr0.52Ti0.48O3 (PZ0.52T0.48) thin films with high polarization are integrated to construct a PZ0.20T0.80–PZ0.52T0.48 multilayer structure to address this challenge. The bottom layer guides the growth of the top layer, while the multilayer architecture redistributes the applied electric field. Furthermore, a one-step annealing strategy is employed to promote interlayer diffusion, forming a transition layer that alleviates interlayer stress arising from thermal mismatch and reduces defects induced by lattice mismatch. As a result, the multilayer film exhibits a high (001) orientation index of 91.83

With the global surge in refrigeration demand, developing efficient, environmentally friendly solid-state refrigeration technologies is urgent. Polymer materials leveraging the electrocaloric effect (ECE) are promising alternatives to traditional vapor compression refrigeration, due to their zero global warming potential and flexibility. This review summarizes progress in polymer-based electrocaloric (EC) material composites from material design to device integration, emphasizing multiscale synergistic design as the core strategy to address polymers' inherent low thermal conductivity and high operating electric fields. We discuss ECE regulation mechanisms and synergistic effects across scales, molecular (defect engineering, high-entropy design), mesoscale (interface engineering), and macroscale (film thickness, external field control). Key challenges (low thermal conductivity, high operating fields) are analyzed, and future work should focus on precise interface engineering and multiscale structural design to advance polymer electrocaloric coolers from lab to commercialization.

Mechanical metamaterials exploit precise control of unit-cell geometry and their macroscopic organization to realize unusual properties. Expanding the capabilities of mechanical metamaterials to incorporate additional functionality remains a challenge. We describe 3D-printed metamaterials embedded with molecular ferroelectrics for use as self-powered pressure sensors. Our gradient lattice design allows for adaptive reconfiguration and controlled deformation-mode transitions, yielding a synergy of low modulus and high load-bearing capacity alongside a monotonic mechanical load-electrical signal response. Furthermore, we implement a modulus gradient in the metamaterials to enhance sensitivity in low-loading regions and extend the detection range across six orders of magnitude. With a combination of high sensitivity and broad detection range, the dual-gradient metamaterials overcome the limitations imposed by the inverse relationships in existing sensors.

Dielectric capacitors featuring high energy density and excellent temperature stability are vital to the miniaturization and reliability of high-power electronic systems. Antiferroelectrics (AFEs) exhibit high polarization through field-induced phase transition. However, their antiferroelectric-ferroelectric phase transition electric field (EAFE-FE) usually exceeds the dielectric breakdown strength, severely restricting their practical energy storage capability. To address this issue, we propose an antiferroelectric/relaxor ferroelectric composite strategy that effectively reduces the EAFE-FE by tuning the phase transition energy barrier, thereby facilitating field-induced polarization switching. The Pb0.94La0.04(Zr0.84Sn0.15Ti0.01)O3/2 wt % 0.8Ba(Zr0.1Ti0.9)O3-0.2 Bi(Zn2/3Ta1/3)O3 (PLZST/2BZT) composite ceramics exhibit a high recoverable energy storage density (Wrec) of 9.3 J cm-3 and an energy storage efficiency (η) of 85% when subjected to a breakdown electric field of 325 kV cm-1. This remarkable performance is owing to the reduced phase transition energy barrier and the enhanced interfacial polarization, which collectively strengthen polarization response. Notably, the PLZST/2BZT ceramics also exhibit exceptional temperature stability, maintaining Wrec above 6.5 J cm-3 and η invariably surpassing 81% over a broad temperature range of -20 to 140 °C under a 320 kV cm-1 electric field. These results highlight the effectiveness of the AFE/relaxor ferroelectric composite strategy for achieving high-performance dielectric ceramics, providing valuable insights into the design of high-performance capacitors for advanced dielectric materials and high-power electronic devices.

The entropy-stabilization strategy through multielement substitution is rapidly developing in ferroelectrics owing to their potentially vast compositional space and striking functional properties. Here, other than focusing on the high-entropy ferroelectrics, we describe a novel low-entropy framework that enables markedly enhanced electromechanical response in lead-free ferroelectric bismuth ferrite (BiFeO3). We reveal the formation of a morphotropic phase boundary (MPB)-like region upon doping multiple elements at a low concentration corresponding to a low-entropy regime, which may rationalize enhanced strain response. As a result, the low-entropy BiFeO3 ceramics exhibit an ultrahigh electrostrain of 1.5%, far exceeding that of pristine BiFeO3. This finding not only widens the entropy regulation method but also may inspire the discovery of new phenomena to develop entropy-regulated ferroelectrics with greatly enhanced functionalities.

The dual requirement of high pyroelectricity and thermal stability presents challenges for eco-detector lead-free ceramics. This work presents a systematic investigation into the mechanism by which MnCO3 doping modulates the pyroelectric properties (p) and depolarization temperature (Td) in 0.8Bi0.5Na0.5TiO3-0.2BaTiO3-xMnCO3 (BNT-BT-xMn, mol%) ceramics. Analysis reveals that Mn2+/3+ ions preferentially substitute for B-site Ti4+ cations, enhancing the structural stability of TiO6 octahedra and significantly increasing Td. Furthermore, the mixed valence states of Mn enhance the polarization of ceramics, leading to an improvement in the pyroelectric coefficient. The optimal composition, BNT-BT-0.4 %Mn, achieves a high pyroelectric coefficient of 2.92 x 10-8 C cm-2 K-1 and a Td of 265 degrees C. Pyroelectric infrared detector fabricated with this ceramic sustains a 2.4 V output signal. This strategy boosts both pyroelectric performance and thermal stability in BNT-BT-xMn, which accelerates practical adoption of lead-free BNT-based ceramics for uncooled pyroelectric infrared detector.

Short-wavelength infrared (SWIR) photodetectors with high performance and complementary metal-oxide-semiconductor transistor (CMOS) compatibility are urgently needed for next-generation imaging and sensing. Traditional SWIR technologies suffer from high cost, complex integration, or poor stability, while Sb2Se3-based materials are limited by narrow spectral response and low quantum efficiency. Here, we report a band-alignment-engineered (Bi,Sb)2Se3 alloy with a gradient Bi composition, forming an intrinsic V-shaped band profile via one-step vapor deposition. This design simultaneously realizes strong SWIR absorption, suppressed dark current, and enhanced directional carrier transport. The photodetector achieves record performance at 1,300 nm (47.8% external quantum efficiency [EQE], 102 dB linear dynamic range [LDR], and 0.32/3.07 μs rise/fall time) and enables monolithic integration with Si readout integrated circuits (ROICs) (640 × 512 pixels) and transparent thin-film transistors (TFTs) for dual-side wavelength-selective imaging. This compositional band-alignment strategy provides a scalable, low-cost route for CMOS-compatible SWIR optoelectronics, promising applications in autonomous vehicles, biomedical imaging, and industrial inspection.

Electrocaloric (EC) refrigeration technology utilizes the reversible temperature change of dielectric materials under an applied electric field to achieve solid-state cooling, demonstrating significant application potential in micro-scale refrigeration due to its compact structure, high energy conversion efficiency, and environmental friendliness. However, its practical implementation faces a critical challenge: the inherent trade-off between an outstanding adiabatic temperature change ( AT ) and a broad operating temperature span (Tspan). This study focuses on the (Ba0.84Sr0.16)(Hf0.07Ti0.93)O3 (BSHT) system, employing a combined strategy of phase transition engineering and chemical modification. By introducing rare-earth La3+ to fine-tune the local structure, lattice distortion, and polar nanoregion (PNRs) reconfiguration were induced, enabling precise control of the ferroelectric-paraelectric phase boundary. Microstructural characterization confirmed the formation of a multiphase coexistence state, while dielectric and ferroelectric analyses revealed optimized phase transition behavior. EC performance tests demonstrated that the 0.01La composition achieved a remarkable AT of 1.73 K under 50 kV/cm while exhibiting a wide Tspan of 61 degrees C (47-108 degrees C), and the 0.02La composition further extended the operational window to 30-102 degrees C (Tspan = 72 degrees C), breaking the conventional trade-off between AT and Tspan. This research provides a novel approach for developing high-performance EC materials that combine both large AT and broad Tspan, advancing the practical application of solid-state refrigeration technology. (c) 2026 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Electrocaloric effect (ECE), a promising candidate for advanced solid-state refrigeration technology, faces fundamental limitations in simultaneously achieving large adiabatic temperature change (Delta T) and broad working temperature span (Tspan). Here, we strategically designed a component system of Ba1-x(Li0.5Sm0.5)xTi1yZryO3 (yBZT-xLS) which establishes the coexistence of multiple ferroelectric phases near room temperature. In this system, the heterovalent Li+/Sm3+ doping at A-site induces relaxor behavior and promotes the coexistence of orthorhombic-tetragonal (O-T) phases around room temperature. Based on this, the addition of Zr4+ at B-site further increases relaxation degree and constructs a broad temperature window with contiguous polymorphic phase transition, thereby facilitating the coexistence of rhombohedral-orthorhombic-tetragonal (R-O-T) phases. Direct ECE measurements on the optimized 0.02BZT-0.08LS composition reveal a maximum Delta T (Delta Tmax) of 2.3 K at 40 degrees C and a broad Tspan (Delta T >= 90% Delta Tmax) over the practical operating range from 20 to 70 degrees C.

Understanding the intrinsic role of piezoelectricity is critical for the rational design of high-efficiency piezocatalytic systems. However, this remains challenging due to the contribution of intrinsic piezoelectricity often being obscured by complex interface effects, specific surface area (size confinement), and other coupled phenomena. In this study, we decouple these factors by employing a model system of piezoceramic thin sheets with a tunable piezoelectric coefficient (d33). We establish a direct and quantitative relationship between d33 and catalytic activity: the sheet with the highest d33 value of 754 pC N−1 exhibited a superior H2O2 production rate of 8.58 μmol h−1 and a Rhodamine B degradation rate constant of 0.073 min−1. Conversely, the sample with the lowest d33 value of 155 pC N−1 showed the minimal activity. Through carrier dynamics analysis and carrier migration simulations, we demonstrate that stronger piezoelectricity enables more efficient polarization rearrangement, greater stress sensitivity, and improved charge separation and transport. These effects lead to a higher transient free carrier concentration and a more robust built-in electric field, which ultimately accelerate the piezocatalytic reaction kinetics. This work establishes a clear and quantitative correlation between intrinsic piezoelectric properties and catalytic activity, while also delivering a high-performance, easily synthesized piezocatalytic platform for sustainable applications.

Next-generation photonics requires advanced electro-optic materials that overcome the limitations of conventional options - LiNbO3 with its high Curie temperature but modest EO response (similar to 30 pm/V) and BaTiO3 with strong EO performance yet poor thermal stability. While Lead Zirconate Titanate (PZT) thin films combine excellent ferroelectric and EO properties, their optimal morphotropic phase boundary compositions with generally higher dielectric constant, face a fundamental tradeoff between enhanced EO coefficients and constrained bandwidth. Here, we engineer Zr-rich rhombohedral-nominal PZT thin films that simultaneously achieve a record effective EO coefficient similar to 212 pm/V (six times higher than LiNbO3). The Zr-rich PZT thin films show unexpected multiple phases mainly composed of rhombohedral and tetragonal phases, rather than purely rhombohedral phase. In situ second-harmonic generation and Raman spectroscopy unveil a phase-transition-mediated polarization reversal mechanism under in-plane electric fields, diverging from conventional out-of-plane switching paradigms. This work challenges the longstanding notion of the phase structure constrained by the composition, and establishes a generalizable strategy-phase and domain engineering-to tailor ferroelectric thin films for ultra-compact modulators, LiDAR, and quantum photonic circuits.

Lead zirconate titanate (PZT) ceramics are extensively utilized in infrared detection applications; however, their relatively low Curie temperature (T-c) of around 230 degrees C, which falls below the 260 degrees C threshold required for integration, limits the miniaturization and integration of infrared detectors. Na0.5Bi4.5Ti4O15 (NBT) ceramics, with a high T-c (similar to 660 degrees C), offer a promising lead-free alternative but require further performance optimization. The distortion of TiO6 octahedra is a well-recognized factor that significantly influences the pyroelectric performance of NBT ceramics. In this study, co-doping Li and Ce into NBT effectively modulated the distortion of TiO6 octahedra, enhanced their tilting and rotational angles, induced defect dipoles, and led to substantial improvements in pyroelectric properties. The optimized Na0.5Bi4.425(Li1/3Ce2/3)(0.075)Ti4O15 (NBTLC-3) composition exhibited a high pyroelectric coefficient of 142 mu C m(-2) K-1, along with outstanding figures of merit, representing the best performance among bismuth layer-structured ferroelectric ceramics. A pyroelectric infrared detector based on NBTLC-3 ceramics demonstrated stable analog output signals even after annealing at 260 degrees C. When integrated into an infrared sensing lighting system, the annealed detector successfully detected human activity within a range of four meters. This study highlights the potential of NBTLC-3 ceramics for infrared detection applications, addressing the growing demands for environmental sustainability, miniaturization, and integration.

Excellent pyroelectric performance in environmentally friendly lead‐free ferroelectrics is highly demanded for uncooled infrared detector. However, the trade‐off between room temperature pyroelectric coefficient ( p room ) and depolarization temperature ( T d ) remains a major challenge of lead‐free ferroelectrics for their device applications. Herein, a superior p room of 13.8 × 10 −4 C m −2 K −1 with high T d of 155 °C is achieved in quenched BNT‐Fe/Mn‐NBT sample. Oxygen vacancy engineering is proposed to solve the constraint between p room and T d in BNT‐based ceramics. The local A/B site displacement and oxygen vacancies are constructed in the BNT‐Fe/Mn‐NBT perovskite structure by quenching treatment, resulting in larger lattice distortion and superior p room . Meanwhile, defect‐induced inhomogeneous random field compensates the ferroelectric depolarization field and down‐shifts the free energy well, maintaining high T d . The resulting pyroelectric infrared detector made from the high‐performance quenched BNT‐Fe/Mn‐NBT generates the voltage responsivity of 5906 V W −1 and specific detection rate of 1.8 × 10 8 cm Hz 1/2 W −1 , which is comparable to the commercial RD‐624 type PZT‐based pyroelectric infrared detector.

Dielectric capacitors with high energy storage performance are highly desired for advanced power electronic devices and systems. Even though strenuous efforts have been dedicated to closing the gap of energy storage density between the dielectric capacitors and the electrochemical capacitors/batteries, a single-minded pursuit of high energy density without a near-zero energy loss for ultrahigh energy efficiency as the grantee is in vain. Herein, for the purpose of decoupling the inherent conflicts between high polarization and low electric hysteresis (loss), and achieving high energy storage density and efficiency simultaneously in multilayer ceramic capacitors (MLCCs), we propose an interlaminar strain engineering strategy to modulate the domain structure and manipulate the polarization behavior of the dielectric mediums. With a heterogeneous layered structure consisting of different antiferroelectric ceramics [(Pb0.9Ba0.04La0.04)(Zr0.65Sn0.3Ti0.05)O3/(Pb0.95Ba0.02La0.02)(Zr0.6Sn0.4)O3/(Pb0.92Ca0.06La0.02)(Zr0.6Sn0.4)0.995O3], our MLCC exhibits a giant recoverable energy density of 22.0 J cm-3 with an ultrahigh energy efficiency of 96.1%. Combined with the favorable temperature and frequency stabilities and the high antifatigue property, this work provides a strain engineering paradigm for designing MLCCs for high-power energy storage and conversion systems.