Physics

The complex generation, transport, and recombination behaviors of charge carriers in perovskite solar cells are fundamentally governed by the diverse orientations, locations, and defect properties of grain boundaries (GBs) in the absorber layer. Herein, we employ 3D TCAD simulations to quantitatively evaluate the correlation between these GB characteristics and device performance metrics, including power conversion efficiency, fill factor, and open-circuit voltage (VOC). We successfully decouple the primary factors and quantify their relative contributions to optoelectronic performance. Our findings demonstrate that transverse grain boundaries (TGBs) form electrostatic barriers that induce severe carrier accumulation and resistive losses. Conversely, vertical grain boundaries primarily induce non-radiative recombination losses while still enabling charge extraction through the grain interior. Notably, owing to the Beer–Lambert carrier generation profile, TGBs adjacent to the hole transport layer induce severe efficiency degradation, with donor-type traps exhibiting a remarkably higher spatial sensitivity than acceptor states. This study provides critical theoretical guidelines for optimizing perovskite film crystallization, interface engineering, and targeted defect passivation.

Power level requirements for near-term and future envisioned 10–100 + kW electric propulsion systems are expected to outpace the capability of ground test facilities to provide an adequate test environment that can either reasonably characterize the spaceflight performance of these thrusters or allow for known facility effect correction methods to be applicable. Limited facility pumping speed and chamber size in current vacuum test facilities are at the crux of the problem and will result in elevated background pressures and electrical coupling with the facility that have not been sufficiently investigated to be corrected for. This work focuses on the impacts of background test chamber pressure on the operation of a 30 cm gridded ion thruster that has a geometry similar to the NASA Solar Technology Application Readiness (NSTAR) thruster. The objectives of this work were to understand the measured deviations of thruster performance from observations of the NSTAR thruster in space by investigating changes in thruster operation over various background pressures. Identified in this work were observations of plume broadening in the wings of Faraday probe sweeps and high ion energies near the neutralizer and plane of the thruster. Other observations included the neutralizer transition flow rate shifted with background pressure and the need for improved correction methods for doubles-to-singles ratios. At a constant thruster throttle level, the corrected production ratio was found not to be consistent over a range of background pressures. Future high-power thruster ground testing will need to account for these observed facility effects if larger and higher pumping speed facilities are not constructed.

We extend an analytical electrical compact model, originally developed for planar InGaN/GaN quantum-well (QW) micro-light-emitting diodes (μLEDs), to core–shell InGaN/GaN QW nanowire-array μLEDs. By exploiting the near invariance of the measured current density–voltage (J–V) characteristics with respect to the number of nanowires, the array can be represented by an equivalent single-nanowire model, enabling extraction of average electrical parameters, including the effective hole diffusion coefficient, as well as the series and thermal resistances. The model enables determination of the hole density injected into the QW and direct extraction of the radiative recombination coefficient B from the dependence of optical power on hole density without requiring specialized measurements. Incorporation of the measured light extraction efficiency and the hole density into the ABC framework allows prediction of the external quantum efficiency (EQE) as a function of both current density and hole concentration. A hole concentration-dependent Auger coefficient is introduced to account for phase-space filling effects at high injection levels, reproducing the observed EQE asymmetry not described by the conventional ABC model. The extracted radiative recombination coefficient further enables evaluation of the modulation bandwidth, which is relevant for visible-light communication applications.

A compact kinetic framework is developed to describe threading dislocation evolution in Ge/Si buffers by linking the final dislocation density to the initial defect level and an Arrhenius-weighted thermal budget that captures the combined effects of temperature, annealing time, and layer geometry. Despite extensive experimental progress in Ge-on-Si integration, optimization of growth and annealing parameters remains largely empirical, owing to the lack of a framework connecting processing conditions to defect evolution. Calibrated against electron channeling contrast imaging measurements from undoped and Sb-doped Ge/Si buffers with different annealing cycle counts, the model captures the overall reduction and saturation trends across the wafer set. This compact framework provides a practical means of assessing how initial defect density and accumulated thermal exposure influence final threading dislocation levels in thin Ge/Si buffers.

Lightwave-driven terahertz scanning tunneling microscopy has attracted considerable interest due to its ability to combine sub-ångström spatial resolution with sub-picosecond temporal resolution. Such measurements require accurate knowledge of the THz near-field transient generated upon coupling the far-field pulse into the junction. Conventional approaches rely on the onset of strong nonlinearity in current–voltage characteristics measured at constant tip–sample distance. Here, combining simulations with experiments exploiting the conduction-band onset of NaCl bilayers on Ag(111), we analyze the determination of the transient amplitude, with particular emphasis on the small-amplitude regime (≲0.5 V). We show that the intrinsic broadening of electronic nonlinearities significantly complicates amplitude extraction. We, therefore, introduce an alternative approach based on constant-current spectroscopy, in which the THz-induced current is measured as a function of sample voltage while the feedback loop maintains a fixed DC current. This method yields a pronounced spectral peak whose amplitude, width, and onset are all sensitive to the transient voltage amplitude, providing multiple independent observables for a more robust determination.

In this study, a low-profile and saw-tooth-shaped slot antenna sensor is proposed for liquid characterization, demonstrating sensitivity to dielectric variations in glucose, saline, and alcohol-based solutions. The antenna consists of a single-layer Rogers 4003C substrate with a rectangular slot integrated with multiple saw-tooth perturbations on the top side and a modified microstrip feedline with a quarter-wavelength transformer on the bottom side. The saw-tooth geometry enhances electric field concentration within the slot region, thereby improving sensitivity to variations in dielectric properties. When liquids with different dielectric constants are deposited on the saw-tooth region of the antenna, measurable resonance frequency shifts occur, enabling material detection. The sensor demonstrated sensitivity in detecting methanol, ethanol, isopropyl alcohol, saline, and glucose solutions. This configuration with dimensions 48 × 48 × 0.508 mm3 (0.78 λo × 0.78 λo × 0.0083 λo at 4.9 GHz, λo represents the free-space wavelength evaluated at the center frequency of the antenna's impedance bandwidth) feasibility for chemical characterization and biomedical sensing applications using an antenna structure.

Brillouin scattering measurements and investigation on AlGaN alloy films with Al compositions of 00.62 from metalorganic chemical vapor deposition are performed. Six elastic constants and bulk modulus of a wide Al-composition range of AlGaN epi-materials are deduced. It is revealed that the elastic constant values of ternary AlGaN with Al compositions of 0.20–0.62 are much greater than those of binary GaN and AlN. It is indicated that the addition of Al in GaN or Ga in AlN has caused a rise in the bulk modulus. The graphical variations and formalized polynomial descriptions of elastic constants and bulk modulus vs Al composition in the full Al range are presented. Brillouin scattering studies on AlGaN alloys address a previously unexplored research gap in wide-bandgap AlGaN semiconductors, as no such studies have been reported so far to the best of our available knowledge. This research and the detailed experimental and calculated data may provide a foundation for more in-depth scientific analyses and future investigations.

Acoustic waves in thin films always suffer from high dispersion, leading to significant sensitivity to film thickness and corresponding device instability in practical applications. The quasi-longitudinal (QL) wave, conventionally classified as a symmetric Lamb wave, is generally considered a low-dispersion plate wave. However, the mechanism responsible for its low dispersion remains underexplored, limiting the excitation and control of QL waves in complex structures beyond simple plates. Here, we show that the QL wave inherits the non-dispersive nature of the longitudinal bulk wave, whereas its dispersion is introduced by coupling with highly dispersive Lamb waves. The coupling strength is governed by their displacement similarity such that reducing their similarity suppresses the coupling-induced dispersion. Based on this mechanism, a surface-wave-like QL wave is excited in an Al/LiNbO3/SiC heterostructure. The similarity between the QL wave and Lamb waves is reduced from 0.57 to 0.16, resulting in extremely weak coupling and a nearly non-dispersive QL wave with a dispersion curve slope of only −2.6 m/s. Acoustic resonators based on this structure show less than 0.8% variation in resonant frequency corresponding to the QL wave when the LiNbO3 thickness varies from 700 to 1100 nm. Our work not only clarifies the fundamental physics of the QL wave and then isolates a nearly non-dispersive QL wave from Lamb waves but also reports a highly robust acoustic resonator that overcomes the notorious sensitivity of resonant frequency to the piezoelectric film thickness.

The optical gain characteristics of InAs/InP quantum dot (QD) laser structures grown on an InP (001) substrate has been investigated at room temperature, using the segmented contact stripe length method. Results show that increasing the QD stacking number to five layers enhances the peak net modal gain to 37.5 cm−1 at 3.6 kA/cm2 and increases differential gain, while the three-layer structures provide a lower peak net modal gain of 31.8 cm−1 at 3.6 kA/cm2 but a broader gain spectra at lower current densities due to a lower total density of states requiring fewer filled states for inversion. Furthermore, the choice of capping materials significantly influences QD formation; using an In0.35Ga0.65As capping layer maintains QD-like characteristics, whereas an In0.45Al0.3Ga0.25As capping layer induces a transition to less localized, QD-like structures with a higher peak net modal gain of 41.7 cm−1 at 3.6 kA/cm2.These results suggest that careful optimization of both stacking number and capping layer composition is essential to balance gain requirements for metal-organic chemical vapor deposition grown InAs/InP QD lasers.

Recent study of granular crystals has provided a unique platform for elastic wave control, facilitating the applications of mechanical functional devices. In this work, we propose a granular-crystal-based motion converter that can convert mechanical vibration into rotation in an extremely low-frequency regime. This converter is composed of two segments of granular chains with distinct angle configurations. The band structures of the two segments exhibit a specific frequency window with the propagation properties of each to be dominated by vibration–rotation-mixed and quasi-pure rotation modes, respectively. This mode-nature difference allows for the propagation of elastic waves through the structure while experiencing a vibration–rotation mode nature conversion. We verified the existence of this vibration–rotation transition effect in the chain through spatiotemporal simulation. Our research provides new possibilities for vibration control and mode conversion at extremely low frequencies.

The effect of atomic-scale surface roughness on electron transport is investigated using 6.5 nm-thick epitaxial Ru(0001) films, a promising metal for next-generation interconnects. Sputter deposition at 350 °C followed by stepwise vacuum annealing to 950 °C yields atomically smooth Ru(0001)/Al2O3(0001) films which are subsequently roughened by depositing ΘRu = 0.5, 1.0, and 2.0 monolayers (MLs) of additional Ru at room temperature. In situ four-point probe measurements show a resistivity ρ = 9.08–9.44 μΩ cm for 6.5 nm-thick films and a 4%–6% increase in sheet resistance upon roughening, attributed to electron scattering at atomic-height surface steps. The measured resistivity penalty Δρr = 0.41 μΩ cm caused by a ΘRu = 0.5 ML coverage suggests formation of 2D islands with an average step-edge separation ls = 2.7 nm, as quantified by a step-edge scattering model. This is in good agreement with ls = 3.6 ± 0.3 nm estimated from atomic force micrographs. Increasing ΘRu further to 1.0 ML causes a slight decrease in roughness and Δρr, indicating coalescence of 2D islands which increases ls to 3.0 nm. However, a ΘRu = 2.0 ML coverage causes 3D mound formation, an increased resistivity penalty Δρr = 0.49 μΩ cm, and a reduced ls = 2.3 nm, consistent with a significant damping of Kiessig fringes measured by x-ray reflectivity. These results demonstrate that atomic-scale topographical variations impose significant resistivity penalties for deeply scaled metallic interconnects.

Dragonflies' exceptional climb capability plays a crucial role in essential survival behaviors such as predation and evasion. However, the climb performance in aerial vehicles remains relatively weak, posing challenges in achieving efficient and stable vertical ascent. To investigate the body motion patterns and wing flapping strategies during climbing flight, this study first conducts biological observations to obtain basic biological characteristics and key climbing parameters. Based on the observational data, numerical simulations are performed to explore aerodynamic performance during ascent. The flow field structures are analyzed through flow visualization. The results show that the dragonfly's climbing process can be divided into four stages, with the average flapping frequency being 28.0 Hz and the total duration being approximately 0.82 s. The ascent is predominantly vertical, with slight backward flight and turning near the end. The angle of attack is essential for regulating flight posture and speed. Meanwhile, by adjusting the flapping plane tilt angle, deviation angle, and amplitude, the dragonfly maintains high lift and stable climbing through the synergistic effects of typical vortex structures such as leading-edge vortices. During the rapid-ascent phase, a significant pressure difference occurs on the wing surfaces along with delayed stall, and rotational circulation is also formed, both of which are key mechanisms for enhanced aerodynamic force generation. Furthermore, the dragonfly dynamically balances lift and flight maneuverability by modulating the phase difference between the forewings and hindwings, with their interaction resulting in a maximum aerodynamic force increase of 25.1%, highlighting the sophisticated aerodynamic strategies during climbing flight.

Far-field radiation pattern is a pivotal metric for characterizing the electromagnetic response of dielectric nanostructures. Traditional full-wave numerical methods, including the finite-difference time-domain (FDTD) method, suffer from high computational cost, whereas pure data-driven deep learning models with limited physical interpretability and fixed angular resolutions require large-scale labeled datasets. Herein, we propose a physics-data hybrid-driven neural network (PDHDNN) that integrates exact multipole expansion, including the electric dipole, magnetic dipole, electric quadrupole, and magnetic quadrupole, as a physical prior for fast and accurate radiation-pattern prediction of silicon nanostructures in the optical near-infrared band. The PDHDNN maps structural parameters and frequencies to low-dimensional multipole moments through neural networks and synthesizes the far-field radiation pattern through a physics-constrained multipole-superposition layer. The predicted total scattering cross sections and radiation patterns agree well with FDTD results, showing low relative errors and high normalized correlation coefficients at resonance peaks. At 1° angular resolution, the PDHDNN reduces data storage by 99.83% and shortens training time by 92.6% compared with a conventional pure data-driven network, while enabling arbitrary-resolution radiation-pattern prediction. This work provides an interpretable, low-cost, and efficient surrogate model for nanophotonic radiation analysis and shows potential for the intelligent design of all-dielectric nanophotonic devices.

Although numerous studies have been directed toward the piezoelectric energy harvesting using phononic crystals, generating high voltage output remains challenging. This is mainly due to the difficulty in optimizing the bandgap to enhance energy amplification. This paper presents a novel design of the phononic crystal structure to enhance voltage generation and overall energy harvesting efficiency. This study presented a phononic crystal that has a unit cell of the cruciform flower shape, enabling the formation of multiple broadened bandgaps that are essential for capturing the vibrations. The wave propagation and energy harvesting performance of the phononic crystal are numerically evaluated using single- and double-defect configurations. The obtained results show that the proposed design effectively increases the multiplicity of the bandgaps. Thus, it results in strong defect mode localization, which generates multiple voltage peaks at various frequencies. The highest peak voltage of 230 V is recorded for the double-defect configuration. The findings of this study hold promise for advances in sustainable energy strategies.

We investigate the spin-pumping efficiency in YIG/W90Ti10 bilayers by measuring the thickness dependence of both the YIG and WTi layers by broadband ferromagnetic resonance (FMR) spectroscopy. The deposition of a 5 nm WTi layer leads to enhanced Gilbert damping in thinner YIG films, indicating efficient spin-current injection. From the spin-pumping contribution to the damping of the YIG/WTi bilayer, we determine an effective spin-mixing conductance of 3.3 × 1018 m−2 for the 5 nm WTi layer. Further measurements with varying WTi thickness reveal a non-monotonic dependence of spin-mixing conductance, peaking at 4.2 × 1018 m−2 for a 3 nm WTi layer. This behavior may be attributed to the chemical and structural phase transition in the WTi layer. Furthermore, comparative analysis with YIG/W bilayers shows that Ti doping significantly reduces geff↑↓. These findings highlight the critical role of alloy composition and structural phase in tuning spin transport for spintronic applications.

remains hindered by the intrinsic limitations of conventional electrolyte chemistry and unfavorable interfacial dynamics. These limitations induce Li dendrite formation, cathode structural degradation, continuous electrolyte decomposition, and progressive interphase deterioration, ultimately compromising the electrochemical reversibility, stability, and safety of LMBs. In this review, we summarize the fundamental challenges limiting LMBs and delineate the essential characteristics of ideal electrolyte chemistry and interfacial stability. Building upon these foundations, recent advances in diverse electrolyte systems are systematically discussed to elucidate how rational electrolyte design dictates solvation structures and interfacial dynamics, which in turn govern ion transport, interphase stability, and the overall electrochemical and practical performance of LMBs. Furthermore, this review highlights the integration of AI-driven electrolyte discovery, in situ characterization, and further summarizes recent progress in their practical validation in high-energy pouch cells and battery devices, thereby accelerating electrolyte design and deepening mechanistic understanding. Finally, electrolyte design principles and future perspectives are outlined to promote the development of practical, safe, and high-energy batteries.

Disruptions in cellular energy metabolism have emerged as central contributors to a broad spectrum of human diseases. While conventional therapeutic strategies can alleviate symptoms, they typically target downstream disease manifestations and often fail to address the underlying energetic dysregulation fueling disease progression. Bioenergetic organelles-engineered from mitochondria and thylakoids-represent a transformative approach by restoring cellular energy homeostasis. Functioning as autonomous metabolic modules, they generate ATP, reductive equivalents, and oxygen in situ, while concurrently modulating redox balance, oxygen tension, and immune-metabolic signaling to restore cellular homeostasis. Recent preclinical evidence highlights their therapeutic versatility, including alleviating tumor hypoxia, restoring bioenergetic function in myocardial and neuronal tissues, reducing inflammatory damage, and normalizing immune cell metabolism. Unlike nanocarriers that primarily serve as delivery vehicles, these bioenergetic organelles actively remodel pathological microenvironments by integrating metabolic restoration with multi-targeted therapeutic actions. This review outlines the design principles, mechanistic basis, and disease-specific applications of artificial bioenergetic organelles, while also addressing key translational challenges such as targeted delivery, immunocompatibility, functional longevity, critical considerations regarding biological safety, and the long-term metabolic fate of these constructs. Positioned at the convergence of bioenergetics, nanotherapeutics, and synthetic biology, these biomimetic systems offer a flexible platform for redefining disease intervention through precise metabolic regulation.

ABSTRACT Commercial photodetectors integrated on readout circuits typically operate under bias voltage, necessitating low dark current density ( J d ) to achieve high detectivity. However, suppressing J d remains a critical challenge for organic photodetectors (OPDs), particularly those operating in the short‐wave infrared (SWIR) region. Herein, we report SWIR‐OPDs that achieve ultralow J d under high bias voltage by developing a narrow bandgap p‐type polymer as the SWIR absorber, thereby establishing an alternative material platform for high‐performance SWIR‐OPDs. The new polymer PDCBT‐DTO2F adopts a push‐pull architecture comprising quaterthiophene donor units and 5,6‐dicyano‐2,1,3‐benzothiadiazole acceptor moieties. Substituting the alkyl chains on quaterthiophene units with alkoxy chains significantly enhanced the intramolecular charge transfer effect and backbone coplanarity. This modification simultaneously yielded intense SWIR absorption, high crystallinity, reduced trap density, and low energetic disorder. Through extensive device optimization, the SWIR‐OPD based on PDCBT‐DTO2F exhibited J d as low as 15.6 nA cm – 2 under −2 V and 58.1 nA cm −2 even under −5 V. Consequently, a detectivity of 1.04 × 10 12 Jones was realized at 1100 nm under −2 V bias, ranking among the best performance for SWIR‐OPDs operating under reverse bias.

Two-dimensional (2D) magnets offer substantial potential for high-density spintronic memory due to their tunable magnetic states, yet a robust, scalable strategy for controlling domain configurations for 2D magnets remains elusive. Here, a selective non-uniform nucleation strategy via chemical vapor deposition is proposed to achieve controlled, non-homogeneous growth of room-temperature ferromagnetic CrTe nanoflakes. This enables bottom-up control of domain evolution by leveraging the strong correlation between the thickness profile and magnetization reversal. The stepwise magnetization reversal in multi-thickness nanoflakes endows CrTe with multiple magnetic states. Utilizing such multi-thickness CrTe nanoflake, a tunable multi-state magnetoresistance is successfully realized in vertical spin valve devices. The controlled synthesis of multi-thickness CrTe nanoflakes signifies a breakthrough in domain-state control in 2D magnet, and establishes a robust material foundation for potential applications in multi-state storage and spin encryption communication.

ABSTRACT Organometallic halide perovskites hold great promise as materials for high‐performance flexible perovskite solar cells (f‐PSCs). However, achieving uniform, highly crystalline, and mechanically robust perovskite films remains a critical challenge for f‐PSCs. Here, a tandem dynamic bond‐based monomer (ADM) was incorporated into a perovskite film, where it cross‐links in situ to control nucleation and crystallization. This enables multi‐modal passivation via Lewis‐base coordination and hydrogen bonding between ADM and the perovskite lattice. The tandem dynamic bonds within the cross‐linked network, preferentially residing at grain boundaries, endow the flexible perovskite films with an instantaneous self‐curing capability under mild treating conditions (40°C for 30 min). As a result, champion devices deliver a power conversion efficiency (PCE) of 27.12% (certified 26.80%) for small‐area rigid PSCs and 20.00% for a flexible minimodule (10.24 cm 2 ), while a large‐area inverted perovskite submodule with an active area of 655.2 cm 2 achieves a record‐breaking PCE of 21.60% and a certified efficiency of 20.37%, demonstrating excellent scalability. Critically, the intrinsic self‐healing capability underpins exceptional mechanical endurance, allowing the devices to maintain more than 91% of their original PCE after 10 000 bending cycles.

Hydrogen-bonded organic frameworks (HOFs) have emerged as promising materials for biomedical applications owing to their metal-free biocompatibility and recyclability. Notably, most HOFs are synthesized and utilized in organic solvents, limiting their biomedical translation. Although water is a biologically compatible alternative, it competes for hydrogen bonding and disrupts interactions between building blocks, making the construction of stable aqueous HOFs challenging. Inspired by the DNA base pairing structure, the first nucleoside-based HOF (N-HOF-1) was developed using a multi-hydrogen bonding strategy. This framework is synthesized entirely in water by simply mixing 2-amino-2'-fluoro-2'-deoxyadenosine (2FA) and cyanuric acid (CA), enabling grade production while maintaining stability under physiological conditions. Microcrystal electron diffraction (MicroED) and single-crystal X-ray diffraction (SCXRD) studies revealed the confinement of M-shaped water clusters within the channels of N-HOF-1, mimicking DNA hydration and preserving the HOF architecture. Notably, the porous and positively charged properties of N-HOF-1 enable interaction with bacteria to form the bacteria-nanoparticle biohybrid systems. Leveraging the intrinsic bioactivity of nucleoside building blocks, this system enhances engineered bacterial colonization in the periodontium, periodontal tissue regeneration, and lymphoma therapy. These findings highlighted the potential of nucleosides as versatile building blocks for hydrophilically stable HOFs, offering new possibilities for their biomedical applications.

ABSTRACT The electrocatalytic chlorine evolution reaction (CER) is central to chlor‐alkali industries and water treatment, yet its practical deployment is still constrained by high energy demands and insufficient selectivity. Here, we report a “mortise‐and‐tenon” strategy using a tulip‐shaped covalent organic framework (Tu‐COF) precursor to construct heteronuclear Ru‐Ln dual‐atom catalysts (Ln = La, Ce, Pr). The pre‐organized micropores of Tu‐COF serve as atomic‐scale nanoreactors, enabling precise confinement and pairing of Ru and lanthanide atoms. Among them, Ru‐Ce delivers outstanding CER performance, achieving 150 mA cm −2 at 1.45 V versus RHE with nearly 100% Faradaic efficiency for Cl 2 evolution and over 500 h stability in a flow cell. Mechanistic studies identify the in situ formed RuCeCl‐N 6 motif as the active site. Density functional theory calculations reveal that adjacent Ce modulates the Ru center's d‐band structure and charge distribution, enhancing initial Cl adsorption on RuCe‐N 6 while optimizing subsequent Cl adsorption on RuCeCl‐N 6 . This lowers the free‐energy barrier for Cl–Cl coupling and suppresses competing OOH * formation, thereby accelerating CER kinetics and intrinsically improving activity and selectivity. This work offers a generalizable strategy for heteronuclear DAC construction and highlights lanthanide‐mediated electronic engineering as a powerful approach to electrocatalyst design.

ABSTRACT Mixed ionic‐electronic transfer (MIET) reactions, such as the oxygen reduction reaction (ORR) at oxide surfaces, are of paramount importance to manifold technologically highly relevant processes, and fundamental understanding must be developed to improve performance and tailor highly efficient electrodes and catalysts. Understanding such complex multi‐step reactions requires the study of kinetic processes, underlying thermodynamic properties, i.e., ionic and electronic defect concentrations, and electrostatic surface effects. However, conventional techniques struggle to uncover the complete picture within the same sample/measurement. Here, we overcome this limitation by introducing bias‐triggered conductivity relaxation (BCR) as a novel tool to investigate MIET reactions on oxides. It is based on alternating out‐of‐plane coulometric titration/polarization and in‐plane electrical conductivity relaxation measurements, providing simultaneous electronic, ionic, and extraordinarily rich surface kinetics information. This innovative combination of electrical and chemical driving forces synergizes information depth, with enhanced time resolution, versatility, and speed, yet it lifts the weaknesses of the individual approaches, while remaining cost‐effective and surprisingly simple. Furthermore, BCR allows to disentangle overpotential induced electrostatic modifications of the surface kinetics in a unique manner. We showcase the advantages of BCR in this work by studying the ORR in model (La, Sr)FeO 3‐δ thin film electrodes and reporting on their thermodynamic and kinetic properties.

Ion-gated transistors inherently exhibit time-dependent behavior governed by ionic motion associated with electric double-layer formation; however, their practical implementation has been limited by insufficient control over ionic dynamics and poor compatibility with scalable thin-film integration. Here, we present carbon nanotube (CNT) solid-ion-gated transistors (sIGTs) that allow the wide-range engineering of ionic dynamics while remaining fully compatible with wafer-scale thin-film processing. Tunable ionic conductance is achieved by ionic content engineering in the film and thickness scaling into the sub-micron regime, enabling ionic time constants from microseconds to milliseconds. CNT sIGTs demonstrate robust DC operation at low ionic content with an optimized polymer matrix and wafer-scale fabrication on flexible substrates. Frequency-dependent gate modulation governed by ionic conductance is systematically investigated through electrical impedance spectroscopy and small-signal analysis, including a comparison of the -3 dB cutoff frequency and the transit frequency. This analysis provides direct insight into the relationship between ionic conductance and frequency-dependent device response, exhibiting consistent trends across both two-terminal and three-terminal device configurations. Monolithic three-dimensional integration of two-tier CNT sIGTs with engineered dynamic responses is demonstrated as a compact dual-timescale physical reservoir for neuromorphic computing that enables classification of time-varying inputs using a single readout layer.

The extensive reliance on animal models in biomedical research motivates the development of advanced in vitro systems that recapitulate physiological complexity while minimizing animal use. Large cellular spheroids can mimic native tissue architecture; however, scalable fabrication of spheroids exceeding millimeter dimensions remains challenging. Here, we introduce a rigid porous capsule (RPC) in millimeter scale, a mechanically robust yet highly permeable platform that imposes external geometric confinement to enable cell-cell aggregation and three-dimensional proliferation. The RPC is fabricated by thermally processing LMs composed of a binary mixture of superhydrophobic particles: meltable poly(octadecyl acrylate) (PODAc) microparticles and non-meltable bovine serum albumin (BSA) nanoparticles. Selective melting of PODAc induces a transformation of the initially fragile, porous LM shell into a rigid and macroporous architecture (pore size in µm scale). By modulating the binary mixture composition, the shell stiffness and porosity are precisely tuned to balance mechanical stability with efficient nutrient transport. The resulting RPCs retain a highly spherical geometry and support 3D cell culture for at least 14 days, enabling the formation of viable, scaffold-free spheroids on a millimetric scale. This RPC establishes a physiologically relevant system for advanced tissue modeling and drug screening.