ACS Applied Electronic Materials最新文献

Perovskite single-crystal sheets (SC-Sheets) stand out in planar integration, surface structural engineering, and superior charge-carrier transport dynamics, solidifying their status as a leading platform for high-performance perovskite optoelectronics. This work presents a laser-direct-writing-enabled fabrication of periodic high-aspect-ratio ridge arrays on MAPbI₃ SC-Sheets. Each engineered ridge operates as a Fabry-Pérot resonator, selectively amplifying near-infrared (NIR) detection sensitivity at target wavelengths through resonance cavity modulation. For devices optimized at 1064 nm, this architecture achieves a responsivity of 241.2 mA/W, On/Off ratio of 2.6 × 10⁴, detectivity of 7.6 × 10¹⁰ Jones, and 28.15% external quantum efficiency, representing 2 orders of magnitude improvement over pristine devices while rivaling single-photon detection thresholds. Critically, laser-induced surface defects exhibit negligible impact on bulk-phase NIR photoresponse within the single-crystal matrix, validating the methodology’s robustness. The technique further demonstrates exceptional scalability and process simplicity, emerging as a manufacturable paradigm for next-generation NIR photodetector industrialization.

High-performance halide-based perovskite memory devices have been developed, exhibiting a variety of synaptic and neuronal functions based on nonvolatile and volatile or threshold switching memristors, respectively, compatible with low power consumption. However, the key ingredient in these perovskite-based systems is the presence of highly toxic lead, which hinders their further development and commercial use. A lead-free perovskite approach for memristive applications could enable sustainable devices, opening the path for practical applications. Herein, we report on the fabrication and characterization of a threshold resistive switching device using solution-based manufacturing, based on a lead-free, all-inorganic perovskite, namely cesium–bismuth iodide (Cs₃Bi₂I₉) perovskite. The memristive device exhibits threshold switching current–voltage (I–V) characteristics with an ON/OFF ratio of >10⁴, while operating in the 0 V–5 V range and exhibiting a cycling endurance of 650 cycles with reproducible behavior. Furthermore, linear long-term, threshold-dependent potentiation protocols, accompanied by abrupt resistance suppression under depression protocols, are demonstrated. The volatile nature of memristive switching allowed the implementation of current spiking activation, similar to neuron spiking protocols, thus opening the path for neuronal emulation. These results can further advance the development of environmentally friendly perovskite memory systems for neuromorphic computing applications, providing a cost-effective alternative to oxide-based devices.

This study investigated the impact of selective oxidation on the core loss of soft magnetic composites. The Fe–3Si–5.5Cr powders were annealed in an atmosphere where Fe was reduced, and Cr and Si were selectively oxidized, forming an insulation oxide layer on the powder surface. To examine the core loss changes due to the insulation coating formed by selective oxidation, the toroidal core samples were fabricated using powders with and without selective oxidation. The core losses of the toroidal core samples fabricated by the selectively oxidized powders were reduced, and as the selective oxidation time increased, the core loss was further reduced. To analyze the cause of the reduction in core loss, the total core loss was separated into the hysteresis, eddy current, and anomalous losses based on the variable separation method. The three losses were reduced in the toroidal core samples fabricated by the selectively oxidized powder. These results confirmed that selective oxidation could form a uniform and dense insulation coating on the Fe–Si–Cr powder, effectively reducing the core loss.

The development of flexible wearable devices requires energy supply devices with high flexibility and stretchability. Thermoelectric ionic hydrogels possess characteristics of high flexibility and stretchability and can be used as heat conversion devices to transform low-grade heat energy into electrical energy. Recently, studies of ionic-thermoelectric hydrogels exhibit high thermopower (or Seebeck coefficient), but their raw materials are typically laced with strong alkalis or heavy metals, which makes them highly toxic and limits their potential applications. In order to enhance the thermopower in this study, we employed PEDOT:PSS as an n-type dopant in PAAm hydrogels to induce counterion condensation. This process immobilizes cations, thereby amplifying the ion-thermal migration rate disparity in the Soret effect and enhancing the thermopower. Furthermore, the thermoelectric performance was optimized by adjusting the dosage of the initiator ammonium persulfate (APS). The experimental results showed that the PEDOT:PSS/PAAm-based ionic hydrogel exhibited a high thermopower of −4.45 mV/K when the concentration of APS was 1 wt %. This study provides an approach for the preparation of low-toxicity, high-thermopower n-type thermoelectric ionic hydrogels.

We present an Al/Cu/GaO_x/Au memristor that combines low-voltage operation (set and reset voltages of 0.48 and −0.3 V, respectively), high cyclic endurance (>13,987 cycles), a large memory window (∼4900), and stable multilevel resistance states. These outstanding properties are achieved by leveraging the synergistic interaction between a Cu-based electrochemical metallization mechanism and a GaO_x intermediate layer. Comparative studies and atomistic simulations reveal that the low energy barrier for Cu diffusion into GaO_x is pivotal in enhancing device performance, enabling superior functionality compared to previously reported GaO_x-based memristors. This memristor supports reliable multilevel resistance programming via compliance current modulation and voltage-controlled filament rupture. Furthermore, its exceptional endurance, among the highest reported for GaO_x memristors, was validated through rigorous current–voltage cycling tests and voltage pulse measurements. This work establishes the Al/Cu/GaO_x/Au memristor as a promising configuration for advancing nonvolatile memory technologies, offering significant potential for high-performance, low-power storage, and neuromorphic computing solutions.

Environmental contamination by heavy metals has become a major health threat, exacerbated by rapid industrialization, thereby creating an urgent demand for highly efficient and sensitive detection devices. In this study, we introduce a highly sensitive triboelectric nanosensor (TENS) based on β-zeolite for multianalytic detection of heavy metal ions. β-Zeolite was spin-coated onto an indium tin oxide (ITO)-coated glass substrate, serving as the tribo-positive layer, while PDMS acted as the tribo-negative layer for self-powered triboelectric sensing signals. The fabricated triboelectric sensor was characterized by an open-circuit voltage of 18.3 V, short-circuit current of 306 nA, and a maximum power density of 602 nW cm^–2 at a resistance of 6 MΩ. Notably, the TENS demonstrated excellent sensitivity in detecting Cd²⁺ (0.3302 ppm^–1) and Hg²⁺ (0.216 ppm^–1) within a detection range of 0.01 to 50 ppm, as well as high selectivity for Cd²⁺, Hg²⁺, and Pb²⁺ ions apart from alkali ions. This straightforward and cost-effective approach to fabricating highly sensitive and selective β-zeolite-based TENSs presents a promising pathway for advancing heavy metal-contaminant detection technologies.

A heterojunction consisting of n-type Ga₂O₃ and p-type NiO thin films is fabricated at low process temperatures. This technology offers the potential to improve heterojunction applications with wide bandgap semiconductors on various substrates. Optical bandgap values of 4.67 and 3.62 eV are obtained for the Ga₂O₃ and NiO semiconductors, respectively, from a Tauc plot. The spontaneously formed depletion region in the heterojunction has capacitive characteristics under thermal equilibrium conditions, while the resistive component is involved in the charge transport under the turn-on voltage ranges. The maximum electric field at the heterojunction interface with 50 nm thick n-Ga₂O₃ is five times higher than that of the n-Ga₂O₃ with a thickness of over 400 nm under thermal equilibrium conditions. When the junction thickness becomes shorter than the junction depletion width, the diode suffers from an early breakdown due to the much higher maximum electric field at the PN junction interface.

In recent years, sodium-ion batteries (SIBs) have emerged as promising alternatives to lithium-ion batteries (LIBs) due to several advantages such as low cost and high abundance of sodium precursors. However, one of the significant drawbacks of SIB cathodes is poor cycling stability at a higher current density than LIBs due to the large size of the Na⁺ ion. We have demonstrated a strategy to boost the cycling stability and overall performance of the SIB cathode via combined dual ion doping and nanostructuring methodologies. We synthesized a series of Na₃V_2–xCo_x(PO₄)₃/C (x = 0.05, 0.1, 0.5) cathode materials via a solid-state sintering process. Structural and morphological properties were analyzed by using XRD, SEM, and TEM analysis. In addition, the successful incorporation of Co was confirmed by an XPS analysis. An aqueous-based electrochemical system was utilized to check the electrochemical performance of the synthesized material. In a 1 M NaOH electrolyte, NCoVP-0.5 delivers the highest discharge time of 175.89 s at a current density of 1 A g^–1. Additional K and Li dopants were utilized to further enhance the performance of NCoVP-0.5. During the initial galvanostatic charge–discharge at a current density of 1 A g^–1 and a voltage window of 0.1–0.58 V, LiNCoVP delivers a discharge time of 202 s with an efficiency of 84.6%, while KNCoVP delivers the highest discharge time of 215 s with an efficiency of 86.2%. Even at a current density of 5 A g^–1, KNCoVP demonstrated a Coulombic efficiency of >97% after 200 cycles. Also, KNCoVP delivers a discharge specific capacity of 116.2 mAh/g at 0.1C. Thus, the introduced material and the demonstrated strategy underscore the inherent problems of the cathode material of SIBs.

A significant challenge with organic devices is simultaneously controlling the lateral sizes and positions of structures at the nanometer scale. This study utilized nanocomposite electron-beam (EB) organic resists due to their excellent electrically conductive components for lateral-scale electronic devices at the nanometer scale. The resist patterning and carrier conduction characteristics of the positive EB resist of ZEP520A containing bis(1-[3-(methoxycarbonyl)propyl]-1-phenyl)-[6,6]C₆₂: bis-PCBM were investigated. Regarding the resist patterning characteristics, line patterns (square patterns) of ZEP520A containing bis-PCBM were successfully implemented with outward widths (side lengths) of less than 200 nm utilizing a straightforward process that only uses EB exposure and development. The disappearance of bis-PCBM aggregations in the line patterns was observed near the sidewalls after development, owing to the penetration of the developer and rinse solution. As the bis-PCBM concentration increased relative to ZEP520A, less voltage was required to produce the same current. The carrier conduction mechanisms can be successfully explained by the fluctuation-induced tunneling conduction theory, which accounts for the thermally increasing temperature dependence of the current at high temperatures and the carrier conduction (similar to the normally temperature-independent tunneling mechanism) at extremely low temperatures. To obtain the current–voltage characteristics of ZEP520A containing bis-PCBM, the voltage drop across the diode with the same layers (but without the composite resist layer) was subtracted from the voltage drop across the entire diode device. The proposed composite resist demonstrates potential for use in highly sensitive biosensors with nanometer-wide channels for multiplexed and simultaneous diagnoses and in organic quantum information devices.