The escalating energy consumption of existing artificial intelligence hardware has become a serious global issue that demands immediate action. Neuromorphic computing offers promises to drastically reduce this footprint. Here, we introduce multicomponent p-type Hf(Sr,Ti)O2 thin films for energy-efficient, resistive switching-based neuromorphic devices. We demonstrate interfacial memristors with ultralow switching currents (≤~10-8 A), exceptional cycle-to-cycle and device-to-device uniformities, and retention >105 s. They reveal hundreds of ultralow conductance levels with a modulation range of >50 (without reaching any saturation) and reproducibly satisfy unsupervised learning rules. This performance originates from incorporating a self-assembled p-n heterointerface between p-type Hf(Sr,Ti)O2 and n-type TiOxNy, resulting in a fully depleted space-charge layer asymmetrically extended into Hf(Sr,Ti)O2, a large built-in potential, and extremely low saturation current density under reverse bias. Ultralow conductance modulation is controlled by tuning p-n heterointerface's energy-barrier height through electro-ionic charge migration. This materials-engineering strategy addresses energy consumption and variability in existing memristors, opening a pathway toward energy-efficient neuromorphic computing systems.

Abstract Oxide-based memristors are promising candidates as neuromorphic hardware in energy-efficient edge computing applications for the Internet of Things (IoT). However, achieving simultaneously optimized memristive and synaptic performance with low-temperature fabrication, compatible with complementary metal-oxide-semiconductor (CMOS) processes, remains a challenge. Here, we demonstrate a dual-function electrode selection strategy—controlled oxygen vacancy electrode reservoir—implemented in a simple, low-temperature-fabricated indium tin oxide (ITO)/WO3/TiN thin film system. We systematically vary the oxygen stoichiometry in the ITO top electrode, which serves not only as an electrical contact, but also as a dynamic oxygen reservoir. A high oxygen-vacancy concentration in the ITO enables optimized memristive performance of low electroforming and operation voltages, and robust memristive and synaptic endurance. This electrode-focused defect engineering approach offers a versatile route to advanced memristor design, enabling many applications in IoT and neuromorphic systems.

Lead-free halide perovskite semiconductors show great promise for light-emitting diodes (LEDs), benefiting from tunable optoelectronic properties and solution processability. However, their practical applications in high-current-density LEDs are fundamentally constrained by severe efficiency roll-off, primarily caused by nonradiative recombination and carrier-induced structural instabilities. In this study, we introduce a molecular N,N'-diphenylthiourea (DPTA)-engineered tin perovskite semiconductor (CsSnI3) that achieves a photoluminescence quantum efficiency (PLQE) of 36% at a carrier concentration of 1018 cm-3. Our approach enables precise control over the charge-carrier concentration and lattice growth. High-resolution transmission electron microscopy further demonstrates that the uniform local strain distribution in the doped films enhances carrier wave-function overlap, leading to a substantial boost in PLQE. Leveraging the enhanced optoelectronic properties of DPTA-treated CsSnI3, we fabricate near-infrared LEDs that exhibit an external quantum efficiency (EQE) of 13.4% and an unprecedented peak radiance of 1248 W sr-1 m-2, with minimal efficiency roll-off even at high current densities exceeding 3500 mA cm-2 in pulse-mode operation. This work introduces a new material-doping strategy for lead-free perovskites, demonstrating their potential for high-power optoelectronic applications and advancing the feasibility of electrically pumped perovskite laser diodes.

Plasmonic nanoparticles play an essential role in improving the sensitivity of different optical methods, and multibranched nanostars are predicted to show the highest enhancement factor for several applications in the near infrared region. The structural complexity of these particles represents a serious challenge with respect to gathering precise knowledge of atomic arrangement and 3D star morphology, making it difficult to accurately predict their optical response and to devise new synthetic methods addressing various applications. Here, we have used 4D-STEM diffraction mapping and a thorough crystallographic analysis to determine leg configuration in space, so that a better understanding of plasmonic properties and growth mechanism can be obtained. Our results show that although electron microscopy images may show a certain shape diversity with stars displaying 4- 5- or 6 branches, the orientation of these legs in space follows the positions associated with the apexes of an icosahedral core. The direct application of the measured star structures has been used as quantitative structural input in optical simulations, which show excellent agreement with experimental measurements. This evidence confirms the crucial role of icosahedral symmetry for explaining the growth mechanism and plasmonic response of gold nanostars with high-aspect-ratio legs.

Achieving ultranarrow spectral linewidth and broad spectral tunability in light-emitting diodes (LEDs) remains challenging due to linewidth broadening from compositional and size heterogeneities. Here we report an interface-regulated vapour crystallization strategy that enables precise control over the spectral linewidth of solution-processed halide perovskite thin films. Underlying materials that exhibit minimal molecular interactions with perovskite precursors, exemplified by poly(9-vinylcarbazole), facilitate smooth ion diffusion and crystallization assisted by dimethylformamide vapour. This mechanism leads to perovskite films with both horizontal and vertical homogeneity and low inhomogeneous broadening comparable to that of perovskite single crystals. We demonstrate perovskite films with ultranarrow photoluminescence linewidths of 13.6 nm, 13.7 nm, 13.8 nm and 14.4 nm for emissions at 464 nm, 474 nm, 483 nm and 522 nm, respectively. This enables us to achieve sky-blue perovskite LEDs with narrow electroluminescence linewidths of 14.7 nm and a peak external quantum efficiency of 24.6%, with comparable linewidths and performance in LEDs spanning the pure blue to pure green. This work offers a practical and scalable strategy to realize narrow spectral linewidth, broad spectral tunability and high performance in thin film LEDs.

Defect engineering has been used for centuries to enhance the mechanical strength of metals and alloys, but its application to cathodes remains largely unexplored. Conventional cathode synthesis aims for defect-free crystals to maximize capacity, but such structures degrade easily through interlayer gliding and microcracking, both of which are reported for single-crystal LiNi0.8Mn0.1Co0.1O2 (SC-NMC811). Dopant substitution or surface coating has been explored to address these issues but introduce foreign elements that complicate recycling. Here, we present a scalable method to introduce a controlled amount (<5%) of Li/Ni anti-site defects that act as “rivets” to suppress interlayer gliding. This moderate defect level enhances the shear strength of SC-NMC811 by 88% and inhibits oxygen loss. The optimized cathodes retain 88.1% capacity after 1,800 cycles (4.3 V) and 80.1% after 900 cycles (4.7 V) using a standard carbonate-based electrolyte. This exceeds conventional SC-NMC811 cycling stability without relying on complicated synthesis procedures or introducing dopants that complicate the recycling process.

The scarcity of Ir presents a major challenge for scaling up its use as a water oxidation electrocatalyst in proton exchange membrane (PEM) water electrolysers. Developing conductive and stable supports is an effective way to reduce iridium loading while maintaining performance. However, the influence of support conductivity and stability on Ir-based catalytic activity remains poorly understood. The behaviour of the support is often obscured in conventional membrane electrode assembly (MEA) systems because IrOx itself is both highly conductive and exceptionally stable. To decouple support conductivity and passivation effects from the intrinsic conductivity of IrOx, we demonstrate a screening platform by studying a series of Ti-Nb alloy thin films produced by sputter deposition and investigate their performance as supports for IrOx water oxidation electrocatalysts. A range of electrochemical tests including accelerated stress tests (AST) were carried out on these samples, where characterisation techniques, including X-ray absorption spectroscopy (XAS), X-ray photoelectron spectroscopy (XPS) and high resolution transmission electron microscopy (HRTEM), demonstrated the in situ formation of passivation layers on these supports during water oxidation. Our results suggest that a similar to 10 nm oxide passivation layer forms on metallic Ti-based supports. On alloying Nb with Ti metal, a more insulating rutile TiO2 phase forms during water oxidation whereas an anatase TiO2, with higher conductivity, is observed on the pure Ti support. Consequently, although alloying Ti with Nb improves the bulk conductivity, the structure of the oxide passivation layer results in a drastic decrease of conductivity and water oxidation activity. Our results demonstrate the importance of the structure and composition of surface oxide phases formed during water oxidation in controlling the overall stability and conductivity of support materials.

Transparent conducting oxides (TCOs) are essential for the optoelectronics industry, but there is a critical gap in cost-effective methods to rapidly deposit low sheet resistance, high transmittance films without damaging delicate materials, including emerging soft semiconductors like metal-halide perovskites. In this work, atmospheric pressure chemical vapor deposition (AP-CVD) is used to synthesise H:In2O3 films with 7.20+/-0.01 Ohm/sq sheet resistance (0.50+/-0.06 mOhm.cm resistivity) and transmittance up to 89

Understanding growth evolution and thereby implementing precise microstructural tuning of two-dimensional (2D) conjugated coordination polymers (cCPs) is crucial to achieve efficient electronic conduction towards their full potential and to observe materials' intrinsic properties. However, fundamental understanding of how 2D cCPs films grow remains very limited. Here, we use copper-benzenehexathiol (Cu-BHT) cCP as a model system to unravel the growth evolution of layered films in liquid-liquid interfacial synthesis in order to identify strategies to achieve tuning of structure-property relationships. We find that thin films formed at the early stage of growth in 20 minutes facilitate smoother, denser, and horizontally oriented films, and thereby achieve higher electrical conductivity of > 3000 S/cm with a metallic temperature dependence down to 20 K. They also reveal signatures of quantum interference mediated weak antilocalisation and Kondo-like effect in magnetotransport at low temperatures. These phenomena are not observed when long reaction time was employed. Our findings offer a new perspective for the growth of dynamically reversible self-assemblies, that is different from the traditional paradigm of longer reaction time being associated with higher ordering and performance, and offer a platform to study spin-related transport properties of these materials with higher performance for advanced electronic, thermoelectric, and potential spintronic applications.

Perovskite light-emitting diodes (PeLEDs) are promising low-cost, solution-processable, and color-pure optoelectronic devices for display and lighting applications. However, blue PeLEDs continue to lag their green and red counterparts in terms of luminance and operational lifetime, limiting their practical implementation. The performance disparity primarily arises from charge injection imbalance, which accelerates degradation at the perovskite/hole transport layer (HTL) interface under electrical bias. Here, we design a polymer blend HTL comprising poly(N-vinyl-2,7-difluoro-carbazole) (PVK-F) and poly(bis(4-phenyl)(2,4,6-trimethylphenyl)amine) (PTAA), in which strengthened van der Waals interactions promote denser molecular packing. This optimized microstructure simultaneously enhances hole mobility and wettability, enabling high-quality perovskite film formation. Consequently, PeLEDs emitting at 485 nanometers achieve an external quantum efficiency of 24.1% and luminance exceeding 26,000 candela per square meter. Moreover, the improved hole injection mitigates interfacial degradation, yielding an operational half-lifetime exceeding 700 minutes at an initial luminance of 100 candela per square meter. This work establishes polymer blending as an effective strategy for advancing the performance and stability of blue PeLEDs.

Low-bandgap Sn-Pb perovskite solar cells are indispensable building blocks for all-perovskite tandems, yet their development is constrained by challenging crystallization control, severe interfacial recombination, and reliance on costly hole transport layers (HTLs) and antisolvent processing involving hazardous and volatile organic solvents. Here, a GuaSCN-assisted vacuum crystallization strategy is developed to realize efficient HTL-free and antisolvent-free Sn-Pb perovskite solar cells. The in-situ photoluminescence evolution is consistent with a cooperative crystallization process, where SCN- regulates early-stage growth while Gua+ facilitates later-stage structural relaxation, enabling sustained optoelectronic improvement during film formation. This synergistic regulation yields compact Sn-Pb perovskite films with a uniform buried interface, reduced structural and compositional heterogeneity, and a surface-associated residual region that may contribute to interfacial passivation. Cross-sectional chemical mapping further shows reduced local compositional fluctuations and interfacial irregularity within the analysed regions. These structural characteristics are accompanied by increased quasi-Fermi level splitting, reduced energetic disorder, and a higher attainable photovoltage of the neat perovskite film. Consequently, HTL-free devices deliver a champion efficiency of 21.4% with a fill factor exceeding 80%, among the highest values reported for HTL-free, antisolvent-free Sn-Pb perovskite solar cells. Furthermore, the GuaSCN-treated narrow-bandgap subcell is integrated into a monolithic all-perovskite tandem device, demonstrating its promise for simplified tandem photovoltaics.

Two-dimensional metal halide perovskites are emerging materials for quantum light emission and neuromorphic computing owing to their quantum-confined structures and tunable optoelectronic properties. Beyond structural dimensionality, the presence of multiple crystallographically distinct halide sites within a single metal halide octahedron presents a unique opportunity to engineer functionality at the subunit-cell level. Here, we report a light-driven, reversible halide-ion isomerization in single-crystalline BA2PbBrxI4-x (BA = butylammonium, x = 1-3), where ions switch between distinct local configurations within individual PbX64- octahedra, without long-range migration or macroscopic phase segregation. Through a combination of hyperspectral imaging, in situ X-ray diffraction, and first-principles calculations, we demonstrate that this intraoctahedral halide site switching modulates the optical bandgap by ∼0.1 eV and enables an estimated reversible electronic bandgap shift of up to ∼0.5 eV. Density functional theory reveals that these changes stem from a redistribution of valence band character, effectively creating chemically distinct optoelectronic isomers that can be activated by light. These results uncover a mechanism of structurally encoded, site-selective photoisomerization in 2D perovskites, offering a new strategy for reconfigurable optoelectronic devices, nonvolatile optical memory, and quantum photonics.

The transition to a green hydrogen economy demands robust, scalable, and sustainable anodes for alkaline water electrolysis operating at industrial current densities (>1 A/cm2). However, achieving high activity and long-term stability under such conditions remains a formidable challenge with conventional catalysts. Here, we report a novel trimetallic CuNiFe anode fabricated through a rapid, single-step electrodeposition process at room temperature without organic additives. The catalyst exhibits an exceptionally low overpotential of <270 mV at 100 mA cm(-2) and operates stably for over 500 hours at 1 A cm(-2) in 30 wt

Halide perovskite light-emitting diodes promise high-efficiency1-3, low-cost optoelectronics, yet their operational instability remains a critical barrier to practical deployment. Here we develop a multimodal in situ electron microscopy approach that integrates four-dimensional scanning transmission electron microscopy, energy-dispersive X-ray spectroscopy and atomic-resolution imaging to directly visualize structural and chemical evolution in a working halide perovskite light-emitting diode with nanometre precision. Our in situ biasing measurements uncover nanoscale structural and chemical transformations initiated at transport layer interfaces, including the formation of metallic lead and lead-rich secondary phases, as well as strain-driven grain fragmentation. On biasing, we observe the partial transformation of the metallic Al contact to insulating AlCl3. Crucially, whereas the bulk of the perovskite emitter remains relatively intact, our experiment shows that degradation is localized at interfaces. By comparing in situ and ex situ measurements, these results establish a mechanistic link between interfacial strain, ionic transport and electrochemical reactions in working devices, and provide a broadly applicable framework for nanoscale degradation analysis in complex multilayered optoelectronic systems using multimodal in situ biasing microscopy.

The instability of metal halide perovskites (PVKs) is a major obstacle to the commercialization of perovskite solar cells (PSCs). While (111)-faceted PVKs exhibit inherent stability, the commonly observed coexisting (100) facets are prone to degradation. Here, we introduce tris(4-formylphenyl)amine (TFPA) into the FAPbI3 PVK. Calculations predict TFPA can preferentially bind onto the (100) facets, increasing the energy barrier for phase transition from alpha-FAPbI3 to delta-phase, and thus stabilizing the PVK structure. In situ grazing-incidence wide-angle X-ray scattering data show that TFPA alters crystal growth to favor (111) facets with face-on orientation. Electron microscopy characterizations reveal that TFPA predominantly localizes at grain boundaries, aligning PVK crystals and suppressing phase transition. Time-resolved terahertz (THz) emission spectroscopy identifies an additional polaron mode that enhances charge carrier transport. TFPA-doped devices achieve a record efficiency of 26.4% (certified 26.1%) for (111) facet-dominated PSCs and retain 96.5% of their initial efficiency after 1,100 h of continuous operation under 1 sun illumination at 65 degrees C.

Lanthanide-doped nanoparticles (LnNPs) exhibit unique optical properties but suffer from severe surface quenching and weak absorption that fundamentally limit their performance. Here, we demonstrate a breakthrough cascade triplet energy transfer (TET) mechanism in precisely engineered NaYbF4@Ca0.8F2:Nd0.2@9-anthracenecarboxylic acid (ACA) heterostructures. This core/active shell/organic molecule configuration combines both molecular sensitization with surface passivation, transforming conventional inert barriers into functional energy conduits. We explore in detail the synthetic conditions required to grow not just optimally active shells but also how best to assemble the organic ligands on the surface of core-shell LnNPs. Systematic shell thickness optimization (0.8-4.6 nm) reveals an optimal shell thickness of ∼2.0 nm. When coupled with an appropriate ligand exchange strategy, we achieve a remarkable 1200-fold emission enhancement compared to bare cores. Comprehensive spectroscopic investigations confirm near-unity TET efficiency and reveal the cascade TET mechanism utilizing Nd3+ ions as energy intermediates to maximize the Yb3+ emission. Thus, our mechanism and heterostructure design present one of the most promising synthetic strategies to overcome the existing limitations of traditional LnNPs, establishing new paradigms for high-performance heterostructures with broad applications in bioimaging, photon conversion, and optoelectronic devices.

The charging time of Li-ion batteries is an important bottleneck in the wider adoption of electric vehicles (EVs). A common strategy to improve the rate performance is improving ion transport by patterning the electrode. However, these patterning methods usually increase the electrode porosity, thereby decreasing the volumetric energy density. In this work, we leverage the ability of Single Crystal LiNi0.8Mn0.1Co0.1O2 (SC-NMC811) electrodes to be calendered to higher packing densities than traditional cathodes, which then allows to offset additional porosity introduced by electrode patterning. We calendar SC-NMC811 electrodes to a 25% porosity and then introduce hole patterns spaced 100 to 600 µm apart using laser processing with a goal to maintain average porosities below 30%. As expected, we found systematic improvements in the rate performance with increasing hole density and used operando charge photometry to explore the limits of mass transport in the regions surrounding the holes but interestingly, we also observe improved capacity retention when using patterned electrodes. We found that there is less cathode lattice oxygen loss when using patterned cathodes, this in turn reduces transition metal shuttling reduces anode solid electrolyte interphase (SEI) impedance growth. We demonstrated a reduction in oxygen loss by both electron energy loss spectroscopy (EELS) mapping, X-ray diffraction (XRD) mapping and X-ray diffraction computed tomography (XRD-CT). Overall, SC-NMC811 electrode's ability to withstand over-calendering offers the opportunity to introduce laser patterned holes while maintaining the average porosity below 30%. This increases both the rate performance and longevity of the electrodes.

Advances in emerging non‐volatile memories demand electrode materials that are complementary‐metal‐oxide‐semiconductor (CMOS) compatible and form atomically smooth, chemically well‐defined interfaces while enabling controlled interfacial oxygen exchange with switching layers. However, few materials simultaneously satisfy these requirements. Here, we demonstrate back‐end‐of‐line (BEOL) compatible, epitaxial WO 3 thin films sputter‐deposited at 400 °C as viable binary‐oxide bottom electrodes. To benchmark structural quality, WO 3 deposited at 500 and 700 °C was used as references, confirming that high‐quality epitaxial growth with smooth interfaces and low defect density can be achieved at BEOL‐compatible conditions. By employing chemically similar electrode and switching materials to minimise interfacial mismatch and promote stable oxygen‐vacancy (V o ) exchange, memristors are fabricated using Hf‐doped WO 3 (WHO) switching layers. These devices show electroforming‐ and current‐compliance‐free interfacial switching, operating voltages ≤±4 V, high resistance uniformity, memory‐switching ratios >130 and endurance >5 × 10 3 cycles. They further demonstrate multiple stable conductance states and linear, symmetric analogue potentiation and depression modulation. The analogue behaviour originates from combined trap‐assisted electronic conduction and field‐driven V o redistribution across an abrupt WHO/WO 3 interface. This work establishes low‐temperature‐grown epitaxial WO 3 as a reliable platform for integrating oxide electrodes into non‐volatile memory and neuromorphic electronics.

Interest in ferroelectric materials for processing, memory, and sensing devices has been re-energized in recent years by the discovery of nanoscale ferroelectricity in insulating binary oxides based on hafnia and zirconia deposited in complementary metal-oxide-semiconductor-compatible processes. However, their large bandgap, very limited doping range, and challenges of high coercive voltage leave the search open for an industry-friendly, low-coercive-voltage, semiconducting ferroelectric for photosensitive and resistive-switching applications. Here, we report the deposition of epitaxial WO3 films at 350 degrees C using a chemical atmospheric process. In these films, anisotropic epitaxial strain imposed by the substrate promotes the stabilization of a polar phase at room temperatures with out-of-plane polarization, evidenced by x-ray diffraction, scanning transmission electron microscopy, piezoresponse force measurements, and Raman spectroscopy. Exploring ferroelectricity in ultrathin epitaxial WO3 films could provide a platform for polarization-controlled electronic and optical applications.