High-responsivity, solar-blind ultraviolet (UV) photodetectors with ultralow dark currents and exceptional photo-to-dark current ratios are essential for next-generation optoelectronic systems. Despite recent progress, achieving simultaneously high responsivity and stringent spectral selectivity remains a significant challenge. Herein, we demonstrate a breakthrough in solar-blind UV detection through rational design of a van der Waals (vdW) heterojunction comprising spatially confined beta-Ga2O3 nanosheets and mechanically exfoliated PdSe2 flakes. The beta-Ga2O3 nanosheets, synthesized via space-confined CVD, exhibit atomic-level uniformity and superior crystallinity, while the narrow-bandgap PdSe2 forms a type-II band alignment that drives efficient interfacial charge separation. This engineered heterostructure delivers an ultralow dark current (similar to 1 pA at 5 V), an extraordinary photo-to-dark current ratio exceeding 106 under 254 nm UV illumination, and a record-high responsivity of 6.17 & times; 104 A W-1 at a modest UV intensity of 251 & micro;W cm-2, among the highest reported for solar-blind detectors based on 2D beta-Ga2O3 heterostructures. This intrinsic wide bandgap of beta-Ga2O3 ensures strict solar-blind operation (200-400 nm), while the vdW interface minimizes trap-assisted recombination and enhances the carrier extraction efficiency. This work establishes a 2D/2D oxide heterostructure platform and interfacial strategy for high-performance UV photodetection, enabling integrable multifunctional optoelectronics with ultralow detection limits and customized spectral responses.

Two-dimensional (2D) wide-bandgap oxides show great potential as candidates for next-generation multifunctional devices. High dielectric (high-kappa) and photoactive 2D NbMoO6 (NMO) is engineered for fieldeffect transistors and ultraviolet (UV) photodetectors. The NMO nanosheets are synthesized by solid-phase calcination, proton exchange, and liquid-phase exfoliation process. NMO, with a high dielectric constant (similar to 31.1), can serve as a gate dielectric for a semiconducting single-walled carbon nanotubes (s-SWCNTs) field-effect transistor, displaying a high on/off ratio of 5 x 104 at a low operating voltage of-5 V. Meanwhile, an individual NMO nanosheet photodetector exhibits high responsivity (210 A/W) and high detectivity (2.58 x1012 Jones) at 3 V at 320 nm. Furthermore, NMO nanosheet film photodetectors show great potential for application in UV image sensing. This work not only provides a new candidate for 2D electronic and optoelectronic devices but also introduces a feasible strategy to explore 2D oxides for various applications. (c) 2025 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Two-dimensional (2D) perovskite oxides exhibit great potential for applications in electronic and optoelectronic devices. Herein, 2D perovskite oxides (NdNb2O7) prepared through liquid-phase exfoliation can be integrated with mechanically exfoliated 2D SnS2 for transistors and photodetectors. Individual NdNb2O7 (NNO) nanosheets with high dielectric constant (34.8), can be used as gate dielectric in transistors with 2D channel materials (SnS2). SnS2 transistors achieved an high on/off ratio of 3×103 at a low operating voltage. The integrated SnS2/NNO device with two testing configurations both exhibits dual-band UV-visible photodetection capabilities by synergistic charge transfer engineering between channel material and gate dielectric. This work provides feasible design strategy for monolithically integrated electronic and optoelectronic devices.

In the post-Moore era, next-generation optoelectronics and neuromorphic computing systems require ultrawide bandgap semiconductors with tunable properties. β-Ga2O3 stands as a promising candidate, possessing a bandgap of 4.5-4.9 eV and a high critical electric field of ∼ 8 MV/cm. However, its practical application is hindered by difficulties in synthesizing high-quality 2D forms and optimizing metal-semiconductor contacts. In this study, highly crystalline ultrathin 2D β-Ga2O3 nanoflakes with improved interface quality and enhanced carrier transport dynamics were synthesized using a space-confined CVD approach. The nanoflakes exhibit excellent structural and crystalline quality, as evidenced by the characteristic peaks in Raman spectroscopy and XRD, along with the clear lattice structure observed via TEM. Metal-semiconductor-metal devices with Ti-Ti, Pd-Pd, and Ti-Pd electrode configurations were fabricated and evaluated through current-voltage and time-resolved current-time measurements. The results reveal that the Schottky barrier height at the metal-Ga2O3 interface plays a decisive role in device performance. Notably, the Ti-Ti device exhibited a distinctive two-stage photocurrent decay after light illumination ceased, attributed to defect-mediated trapping and release of photogenerated carriers. By incorporating this unique photoresponse behavior into a deep neural network, promising image recognition accuracy was achieved on the Modified National Institute of Standards and Technology data set. This work not only offers a reliable pathway for synthesizing high-quality 2D β-Ga2O3 but also demonstrates its potential for application in high-performance optoelectronics and neuromorphic computing.

The unstable configurations and uncontrollable stoichiometric ratios of atomically-thick one-dimensional (1D) magnets pose challenges for practical applications. Here, we employ a spatially confined domain strategy to obtain 1D vanadium tellurides (VxTey) with distinctive stoichiometry within single-walled carbon nanotubes (SWCNTs). Confined by SWCNTs with different inner diameters, three unconventional air-stable VxTey can be generated: 1D 1H-VTe2, V6Te6, and VTe3. Atomically resolved electron microscopy systematically unveils the conformational distributions of these three phases inside SWCNTs. Density functional theory (DFT) calculations indicate that these diverse VxTey phases exhibit different intrinsic electronic structures, which correspond to ferromagnetic, antiferromagnetic, and non-magnetic properties. Furthermore, the magnetic response and magnetic anisotropy of the 1D VxTey@SWCNTs assembly are experimentally confirmed. This work highlights the preparation of air-stable atomic 1D magnets, offering promising solutions for the design of next-generation spintronic devices.

Two-dimensional (2D) oxide perovskites show great potential as candidates for next-generation electronic and optoelectronic devices. For the first time, 2D ferroelectric perovskite Bi2WO6 (BWO) is used for engineering multifunctional electronic and optoelectronic devices, including transistor, photodetector, and photosynapse devices. The well-defined BWO nanosheets (E-g approximate to 2.75 eV) are synthesized by the chemical vapor deposition method and exhibit distinct out-of-plane and in-plane ferroelectric polarization. The individual BWO nanosheet device shows significant n-type transistor characteristics with a clockwise hysteresis. Meanwhile, the individual BWO nanosheet device can emulate light-induced synaptic functions such as "learning-forgetting-relearning" behavior. Furthermore, the individual BWO nanosheet photodetector exhibits outstanding photodetection performance at 3 V at 350 nm, including high responsivity (27.2 A W-1) and high detectivity (6.9 x 10(11) Jones). This work not only provides a new candidate for 2D electronic and optoelectronic devices for various applications but also lays down the foundation for the future development of integrated sensing, storage, and neuromorphic computing devices.

With the rapid advancement of electronic device miniaturization, materials are required to possess stronger conductivity at smaller scales. Single-walled carbon nanotubes (SWCNTs) have drawn significant interest due to their outstanding theoretical electrical properties. However, improving their electrical performance remains a significant challenge. In this study, continuous one-dimensional (1D) tellurium (Te) atomic chains were successfully synthesized inside SWCNTs, enabling efficient and stable doping. Unlike previous powder-based studies, polymer-assisted selective sorting was utilized to achieve high-purity Te-filled semiconducting SWCNT (Te@s-SWCNT) solutions. Compared to pristine SWCNTs, Te@s-SWCNT transistors exhibited more than a 4-fold increase in on-state current density. Individual Te-filled metallic SWCNTs (Te@m-SWCNTs) demonstrated current-carrying capacity, achieving current densities ranging from 1.3 to 4.6 × 109 A/cm2. Theoretical calculations revealed that these improvements result from charge transfer effects between Te and SWCNTs. This research provides a robust foundation for developing next-generation 1D carbon-based electronics.

The application of 1D halide perovskite heterostructures based on single‐walled carbon nanotubes (SWCNTs) is always an unresolved challenge. Herein, for the first time, 1D van der Waals heterostructures based on CsPbBr 3 encapsulated within semiconducting SWCNTs (CPB@s‐SWCNTs) are engineered for negative dual‐band photodetectors via inner and outer charge‐transfer engineering. The individual CPB@SWCNT device exhibits a negative light response and achieves a significant n‐doping effect. Theoretical calculations illustrate that the electrons transferred from CPB to SWCNT are 0.61 e per cell. More importantly, the CPB@s‐SWCNTs are successfully separated, and large‐area CPB@s‐SWCNTs film devices exhibit obvious negative light response (−10.3 A W −1 ) at 3 V at 510 nm. Interestingly, integrated CPB@s‐SWCNTs film with SrTiO 3 substrate device shows negative dual‐band light detection (−5.8 A W −1 at 520 nm and −5.2 A W −1 at 400 nm). Kelvin probe force microscope tests indicate that electrons are transferred from CPB and SrTiO 3 to SWCNTs through inner filling and outer integration. This work not only provides a general strategy for the separation, assembly, and device integration of halide perovskite‐filled SWCNTs, but also expands their application in optoelectronic devices.

One-dimensional (1D) perovskite heterostructures fabricated through the template method employing single-walled carbon nanotubes (SWCNTs) have garnered significant attention due to their distinctive structural properties. Nevertheless, substantial challenges remain in the device applications of 1D halide perovskite heterostructures due to the separation issue of the semiconductor SWCNTs (s-SWCNTs) after encapsulating the perovskite. Here, we report 1D perovskite heterostructures based on CsPbBr3 encapsulated inside s-SWCNTs (CPB@s-SWCNTs), realizing editable photoresponse. 1D perovskite heterostructures were verified by high-angle annular dark-field scanning transmission electron microscopy. The CPB-filled s-SWCNTs were successfully separated, achieving a significant n-doping effect and a weak negative response. Density functional theory calculations show that electrons are transferred from the CPB to SWCNTs at 0.61 e per SWCNT unit cell. Kelvin probe force microscopy shows that the surface potential of CPB@s-SWCNTs is higher than that of s-SWCNTs. The integrated CPB@s-SWCNTs film, when coupled with a GaN wafer device, demonstrates an editable photoresponse, including enhanced negative response (n-GaN), asymmetric positive response (p-GaN), and ultrahigh photoresponse at 0 V. This study provides an effective strategy for fabricating large-area s-SWCNTs films filled with various perovskite materials, thereby broadening the application of 1D van der Waals heterostructures in optoelectronic devices.

The development of tunable and highly controllable photoconductive devices for brain-inspired optical neuromorphic systems remains challenging. Previous neuromorphic devices are limited by asymmetric and nonlinear conductive properties, which impose specific restrictions on training tasks and weight learning rules in dynamic and complex visual environments. A programmable synaptic transistor based on a Se@SWCNT 1D van der Waals heterojunction, enabling gate-controlled positive and negative responses is presented. This approach eliminates the need for multilayer heterojunctions or complex circuits, simplifying array integration and wafer-scale fabrication. This phototransistor shows improved symmetry and linearity (R2 > 0.99) in weight variation following optical stimulation, and simultaneously achieves linear persistent photoconductivity and negative photoconductivity with over 128 memory states, which is not reported previously. By adjusting light intensity and wavelength range, consistent weight rule processing across three tasks of increasing complexity is demonstrated. Notably, different visual tasks require distinct neural structures and decay rates. The proposed transistor facilitates transitions between bio-inspired brain regions via optical hybrid programming, adapting to dynamic visual environments. This innovation contributes significantly to brain-like computing and bio-inspired vision, due to its exceptional accuracy and dynamic switch models.

Two-dimensional (2D) perovskite oxides have garnered significant interest owing to their potential applications in multifunctional electronic and optoelectronic devices. In our work, the engineering of 2D perovskite PrNb2O7 (PNO) is explored to advance multifunctional electronic and optoelectronic applications. The PNO nanosheets are prepared using a two-step method, which involved solid-phase calcination for precursor synthesis and subsequent liquid-phase exfoliation. PNO nanosheets exhibit a high dielectric constant (21.6), enabling their use as gate dielectrics in semiconducting single-walled carbon nanotubes (s-SWCNTs) transistors. The resulting devices demonstrate a high on/off ratio of 1 × 106 at a low operating voltage of 5 V. Furthermore, individual PNO nanosheets photodetectors show outstanding performance under 280 nm ultraviolet irradiation at 3 V, featuring a high responsivity of 66.7 AW-1 and a specific detectivity of 3.4 × 1012 Jones. Additionally, PNO nanosheets devices successfully emulate light-induced synaptic behaviors, including "learning-forgetting-relearning" dynamics. This work not only establishes PNO as promising candidate material for 2D electronic and optoelectronic devices, but also paves the way toward future integrated devices for sensing, memory, and neuromorphic computing.

The applications of one-dimensional (1D) halide perovskite heterostructures based on single-walled carbon nanotubes (SWCNTs) remain an unresolved challenge. Herein, 1D van der Waals heterostructures composed of CsPbI3 (CPI) encapsulated within semiconducting SWCNTs (CPI@s-SWCNTs) are designed for negative photodetectors and photosynapse devices via modulable photocarrier engineering. A single CPI@SWCNT device demonstrates a notable n-doping effect and exhibits negative photoresponse. Theoretical simulations reveal that the electrons transferred from CPI to SWCNT amount to 0.73e/cell. Large-area CPI@s-SWCNTs film can be obtained through the separation using the ultraviolet (UV) photosensitive polymer poly[9-(1-octyl-9H-carbazol-9-yl)-nonyl] (PCz). Under visible light irradiation, the large-area film device exhibits remarkable negative photoresponse (-9.3 A/W) owing to the photoelectric effect of internally filled CPI. Under UV irradiation, the film device exhibits synaptic behavior of electrical writing and optical erasing due to the persistent photoconductivity effect of the surface polymer PCz. This work not only provides a general strategy for the separation and application of halide perovskite filled SWCNTs, but also paves the way for broader applications of 1D van der Waals heterostructures in multifunctional optoelectronic devices.

Over the past decade, the library of two-dimensional (2D) niobate perovskites has been significantly expanded, featuring a wide array of intriguing properties such as exceptionally large specific surface area, outstanding flexibility and transparency, high chemical stability, and unique physical characteristics (including dielectric, ferroelectric, and semiconducting behaviors). The huge possibility to achieve controllable nanosheet characteristics such as composition, size, shape, and thickness by modifying the layered parent compound and the following exfoliation technique presents vast opportunities for achieving tunable functional properties. Additionally, the unique nature of 2D niobate perovskites have made them promising material candidates for multifunctional applications, such as photodetectors, phototransistors, photocatalysis, dielectric applications, etc. This review provides a concise overview of recent developments in the research on 2D niobate perovskites exfoliated from layered perovskite oxides, with emphasis on their microstructural, optical, dielectric and semiconducting properties. This review also explores the use of these materials in diverse applications, including microcapacitors, phototransistors, photodetectors, photocatalysis, and as functional elements in luminescence, nanofiltration, anticorrosion, template-assisted film growth, and more. Finally, we provide a perspective into material design and property regulation for widespread applications, highlighting the challenges associated with these efforts.

High-entropy oxides (HEOs) are emerging as highly promising materials for electrochemical applications due to their exceptional electronic properties and active sites. However, the synthesis of 1D HEO with high aspect ratios and mechanical properties has been challenging, particularly on an industrial scale. Herein, we report a spatially confined oxidation (SCO) method to synthesize 1D HEO@SWCNTs with high specific surface area and stability. This method enables the large-scale production of HEO@SWCNTs, achieving quasi-industrially quantities in a single batch, and can be extended to seven-element 1D HEO. The resulting exhibit a homogeneous distribution of elements and a single-phase solid solution structure, as confirmed by STEM-EDS and XRD analysis. The Fermi level of SWCNTs is downshifted into the valence band upon HEO doping, enhancing conductivity and electrochemical activity. The HEO@SWCNTs electrode demonstrates superior flexibility and self-supported properties, making it suitable for large-scale electrochemical applications. Chronoamperometric measurements reveal excellent stability, maintaining 94% current retention after 20 h. Notably, in the electrochemical epoxidation reaction cycloolefin, the HEO@SWCNTs self-supported electrode achieves an average FE of 70.7% for epoxy-cyclohexane over 24 h. This work provides a scalable and versatile approach to the synthesis of self-supported electrodes for advanced electrochemical systems.

Ferroelectricity in ultrathin 2D materials has garnered significant attention owing to its potential applications in nonvolatile memory, nanoelectronics, and optoelectronics. However, the exploration of ferroelectricity in materials possessing inherent centrosymmetric or mirror symmetry, particularly in the 2D domain, remains limited. In this study, the chemical vapor deposition (CVD) technique is utilized to synthesize ultrathin Bi2WO6 (BWO) nanoflakes, revealing robustly intercorrelated out-of-plane (OOP) and in-plane (IP) ferroelectric polarization. The measured ferroelectric phase transition temperature of ultrathin BWO nanoflake is approximate to 800 K. The emergence of OOP ferroelectricity in BWO nanoflake is ascribed to the displacement of oxygen vacancies between neighboring asymmetric sites, leading to the disruption of local structural mirror symmetry and the alignment of dipole moments. Moreover, the IP and OOP ferroelectric responses are modulated by distinct maximum bias voltages. This investigation offers novel insights into the advancement of 2D ferroelectrics with elevated Curie temperatures.

We first report two-dimensional H4Nb6O17 nanosheets for high performance ultraviolet photodetectors (UV PDs). The H4Nb6O17 nanosheets are synthesized through a simple solid-state reaction and liquid exfoliation technique. The individual H4Nb6O17 nanosheet device displays outstanding UV-detecting performance, including high responsivity (3.8 AW(-1)), high detectivity (1.6 x10(12) Jones), and fast response speed (1.5/138 ms) at 300 nm light irradiation at 3 V bias. Furthermore, the H4Nb6O17 nanosheets film is fabricated via an easy drop-coating process, and shows high transparency (>75%) in the visible light range. More importantly, the H4Nb6O17 nanosheet film device exhibits satisfactory photocurrent (12 nA) and on/off ratio (100), and maintains excellent performance after many bending tests. This work not only introduce a promising candidate for UV PD, but also suggests the broad prospect of H4Nb6O17 nanosheets in wearable electronic devices in the future.

Crystallization, while a common process in nature, remains one of the most mysterious phenomena. Understanding its physical mechanisms is essential for obtaining high-quality crystals. Typically, crystals grown by thermal evaporation or sublimation nucleate the substrate facing the evaporation source. Here, a novel vapor micro-turbulence mass transport mechanism in the growth process of ultrathin BiOCl single crystals has been revealed. In this mechanism, the precursor vapor bypasses the solid substrate, forming micro-turbulent vaporizing flows to nucleate on the surface of the substrate facing away from the evaporation source. Considering nucleation kinetics, fast shear flows are known to cause secondary nucleation, increasing nucleation quantity while decreasing the final size of the crystals. Thus, the nucleation and growth process of BiOCl crystals are controlled by adjusting the micro-turbulence intensity to reduce shear flow energy and dilate phase distribution, resulting in BiOCl crystals with uniform distribution and regular shape. Subsequent structural and morphological characterization confirms the high crystallization quality of the obtained crystals, and the performance of the constructed solar-blind photodetectors is comparable to that of similar devices. These findings contribute to a deeper understanding of vapor mass transport and crystal growth techniques and may be useful for applications related to metal oxide crystals.

Abstract Solid‐state batteries (SSBs) are attracting growing interest as long‐lasting, thermally resilient, and high‐safe energy storage systems. As an emerging area of battery chemistry, there are many issues with SSBs, including strongly reductive lithium anodes, oxidized cathodes (state of charge), the thermodynamic stability limits of solid‐state electrolytes (SSEs), and the ubiquitous and critical interfaces. In this Review, we provided an overview of the main obstacles in the development of SSBs, such as the lithium anode|SSEs interface, the cathode|SSEs interface, lithium‐ion transport in the SSEs, and the root origin of lithium intrusions, as well as the safety issues caused by the dendrites. Understanding and overcoming these obstacles are crucial but also extremely challenging as the localized and buried nature of the intimate contact between electrode and SSEs makes direct detection difficult. We reviewed advanced characterization techniques and discussed the complex ion/electron‐transport mechanism that have been plaguing electrochemists. Finally, we focused on studying and revealing the coupled electro‐chemo‐mechanical behavior occurring in the lithium anode, cathode, SSEs, and beyond.

In-situ reconstruction of 2D materials' electrical charge facilitates manipulating their properties for various applications. Herein we propose on-device charge reconstruction to achieve high-performance photodetectors. The Pb2Nb3O10 (PNO) nanosheets are prepared by solid-phase calcination and liquid-phase exfoliation process. The individual PNO nanosheet photodetector shows high responsivity (7.2 AW- 1 ) and detectivity (3.5*1011 Jones) at 3 V at 380 nm. The individual PNO nanosheet device can be transformed into (Ag)PNO device by in-situ exchanging charge in the device channel. The (Ag)PNO device achieves greatly enhanced responsivity (1141 AW-1) and detectivity (4.1*1013 Jones) at 3 Vat 380 nm. This work highlights on-device charge engineering as a potential method to exploit 2D materials' fundamental properties for various applications.