ACS Applied Electronic Materials最新文献

Thin-film transistors (TFTs) based on oxide semiconductors, represented by indium-gallium-zinc-oxide (IGZO), are widely used in the display industry and are increasingly required to operate in flexible form factors such as wearable devices and foldable displays. Although thin-film amorphous oxide semiconductors are flexible, the brittle layers in the devices are damaged under sharp or repeated bending. Strategies such as ultrathin substrates and neutral-plane engineering can mitigate the strain applied to the devices; however, they constrain the substrate handling or the device architecture. We propose a strain-attenuating substrate in which a low-modulus elastomer, polydimethylsiloxane (PDMS), is entirely encapsulated inside chemically and thermally stable polyimide (PI). The embedded PDMS reduces the strain applied to the substrate surface, and the PI encapsulation provides high thermal endurance for process compatibility with metal oxide TFT fabrication. The IGZO TFTs fabricated directly on the strain-attenuating substrate maintain their electrical characteristics after bending at a radius of 1.5 mm, with a mobility change of –0.03% and a threshold voltage shift of 0.07 V, whereas the TFTs on a conventional PI substrate of the same thickness show a mobility decrease of 74.53% and a threshold voltage shift of 3.84 V.

Zinc-ion batteries (ZIBs) are promising candidates for large-scale energy storage owing to their high theoretical capacity, low cost, environmental benignity, and intrinsic safety. However, their practical application remains limited by interfacial side reactions at the Zn anode and insufficient electrolyte stability. Herein, a zeolite/PEG comodified PVA hydrogel electrolyte was developed by incorporating LTA zeolite and polyethylene glycol (PEG) into a poly(vinyl alcohol) (PVA) matrix. LTA zeolite enhances water retention, regulates Zn²⁺ transport, and improves electrolyte stability by confining free water, whereas hydrogen-bonded network between PEG and PVA improves mechanical flexibility and provides more continuous ion-conduction pathways. Owing to the dual effects of PEG and zeolite, PZ-10 retained water for 48 h and exhibited an elongation at break of 420%, while PP5-Z-10 maintained flexibility after 72 h and achieved an ionic conductivity of 1.72 × 10⁻² S cm⁻¹, 5.2 times that of pristine PVA. When assembled into ZIBs, the PP5-Z-10 electrolyte delivered a specific capacity of 190.1 mAh g⁻¹ at 50 mA g⁻¹ and retained 86.7% of its capacity after 500 cycles at 1000 mA g⁻¹. These results demonstrate that the dual action of PEG and zeolite effectively improves the durability, ionic conductivity, and cycling stability of PVA-based hydrogel electrolytes, providing a practical strategy for stable Zn-based energy storage devices.

Wearable sensors are increasingly vital for health monitoring, human–machine interaction, and flexible electronics, yet their fabrication often relies on costly, multistep processes with limited scalability. In this work, we report a first ever cold spray deposition approach for fabricating flexible wearable pressure sensors using graphene nanoplatelets (GNPs) on flexible polydimethylsiloxane (PDMS) polymer. The cold spray technique enables direct, binder-free deposition of sensing films on flexible substrates, ensuring strong adhesion, mechanical robustness, and scalable manufacturing. The fabricated sensors exhibit a high sensitivity of 12.13 kPa^–1, excellent durability with over 5000 stable cycles, and rapid response characteristics (12.66 ms rise time and 16.62 ms fall time). Demonstrated in real-time pulse waveform monitoring, the device highlights its potential for continuous health tracking and wearable biomedical applications. This study establishes cold spray deposition as a promising and scalable route for next-generation flexible sensors and wearable electronics.

Ultraviolet (UV) detection, owing to its excellent noise immunity, is widely used in ultra-high-voltage power grid corona monitoring, fire warning, missile tracking, and medical imaging. Zinc oxide (ZnO), a wide-bandgap semiconductor, shows strong potential due to its inherent UV spectral selectivity. However, intrinsic unintentional doping defects in ZnO single crystals lead to a high background carrier concentration, which causes excessive leakage current in ZnO-based devices and limits their performance in detecting weak UV signals. In this work, by introducing a high-κ lanthanide oxide heterostructure, we achieved a pA-scale background current in a device based on a natural ZnO single crystal. A polycrystalline ytterbium oxide (Yb₂O₃) thin film was sputter-deposited on ZnO single crystals to form a Yb₂O₃/ZnO heterojunction, which reduced the dark current by 8–9 orders of magnitude in the fabricated Au/Yb₂O₃/ZnO metal-insulator-semiconductor (MIS)-type photodetector. The heterojunction device exhibits a notable photoresponse under 365 nm illumination, with a response time of 188.9/153.4 ms and a photocurrent-to-dark-current ratio (PDCR) of approximately 250. These results demonstrate that high-κ lanthanide oxide can be effectively used to construct heterostructures for ZnO single-crystal devices, providing a promising pathway toward developing filter-free and highly integrated ZnO single-crystal UV imaging systems.

Nonvolatile memory platforms that avoid conventional floating-gated charge-storage layers are attracting increasing interest for next-generation data-centric electronic systems. In this work, we present a Sn-doped β-gallium oxide (β-Ga₂O₃) metal–insulator–semiconductor field-effect transistor (MISFET)-based optoelectronic memory (OEM) device that utilizes intrinsic deep-level trap states in the β-Ga₂O₃ channel as nonvolatile charge storage sites. The β-Ga₂O₃ OEM device exhibits stable transistor operation with a high drain current on/off ratio (>10⁵) and a near-ideal subthreshold slope (60 mV/dec). In addition, programmable threshold voltage (V_th) modulation is achieved through electrical erasing (EE) and optical programming (OP) processes, resulting in a wide memory window of 4.2 V by applying an EE pulse of 4 V and an OP pulse under 405 nm deep blue illumination. The optically and electrically defined memory states show stable memory retention (>10³ s) and memory endurance (>10³ cycles). Furthermore, we integrate the OEM device into a resistive-load inverter circuit to demonstrate memory-state-dependent logic operation. By modulating the memory state, the same circuit can be reconfigured between a conventional inverter mode and an input-independent logic mode. These results highlight the potential of the β-Ga₂O₃ OEM as a scalable platform for next-generation nonvolatile memory technologies.

Photodetectors are essential optoelectronic components for biotechnological sensing and optical communication systems. Perovskite materials, owing to their broad spectral absorption, high charge-carrier mobility, mechanical flexibility, and solution processability, have emerged as promising candidates for next-generation photodetection. In this work, a block copolymer composed of polydimethylsiloxane (PDMS) and maltotriose is introduced as an interfacial modifier to regulate the crystallographic, morphological, and optoelectronic properties of perovskite thin films, thereby enhancing phototransistor performance, particularly under weak-light conditions. Copolymers with different architectures exhibit distinct surface energies, enabling efficient charge transfer between perovskite polycrystalline grains and hydroxy-rich carbohydrate segments, which effectively shortens exciton lifetimes and suppresses recombination. Notably, perovskite phototransistors incorporating a two-armed branched PDMS-block-maltotriose achieve the highest device performance under 455 nm illumination. Even at an ultralow light intensity of 0.20 μW cm^–2, the device exhibits a responsivity of 0.37 A W^–1 and a detectivity of 4.0 × 10⁹ Jones, demonstrating excellent sensitivity. This performance enhancement is attributed to PDMS-directed microphase separation that spatially accommodates perovskite nanocrystals within the carbohydrate matrix, where abundant hydroxy groups passivate surface defects through hydrogen bonding or Pb²⁺ coordination. These results highlight the potential of block-copolymer/perovskite nanohybrids for high-performance weak-light phototransistors.

Abnormal humidity in high-voltage substations poses a critical threat to the insulation safety of electrical equipment. Conventional humidity sensors rely on external power sources or batteries, which limits their feasibility for distributed deployment in complex electromagnetic environments. In this work, a self-powered wireless humidity monitoring system is developed by integrating a CeO₂/Ag heterojunction composite sensor with a triboelectric nanogenerator (TENG) and a self-starting power management module, enabling ambient wind energy harvesting. The CeO₂/Ag composite is synthesized via a hydrothermal method followed by in situ reduction. Characterization results reveal that Ag nanoparticles are uniformly distributed on the CeO₂ surface. The sensor operates over a wide relative-humidity range of 0–97% RH and reaches a maximum response of 96.98% at 97% RH, with response and recovery times of 8.7 and 17.9 s, respectively. Density functional theory calculations demonstrate that the CeO₂/Ag heterointerface significantly enhances water molecule adsorption and charge transfer through Schottky barrier modulation, with an adsorption energy of –1.447 eV. The TENG achieves a peak power of 732 μW, and the integrated system enables wireless data transmission every 75 s at a rotational speed of 200 rpm. This work offers a promising solution for self-powered, distributed humidity monitoring in substations and other complex industrial environments.

A series of pyrazole-functionalized quinolines with donor–acceptor (D–A) and donor–acceptor–donor (D–A–D) architectures was synthesized for application in multilevel organic memory devices. The donor substituents, such as tert-butyl and methoxyphenyl groups, as well as the functionalization of the pyrazole moiety on the quinoline, enable the transition from binary to ternary and quaternary memory states, thereby enhancing charge storage density. Notably, quaternary memory devices, which are rarely reported, have three ON states and one OFF state, enabling multilevel data storage and allowing two bits to be stored in a single memory cell. These devices exhibit low threshold voltages of –0.58 to –3.09 V and ON/OFF ratios of 10² to 10⁵, thereby improving memory device performance. Photophysical and electrochemical analyses indicate enhanced charge-transfer capabilities, as evidenced by a red shift in the absorption spectra and reduced band gaps (3.02–3.15 eV). All compounds demonstrated nonvolatile write-once-read-many memory behavior, in which charge transport is primarily influenced by intramolecular charge transfer and trap-controlled space-charge-limited current mechanisms. The devices also exhibited significant stability over 100 reading cycles and 2000 s under constant stress at 0.5 V. The observed memory performance is strongly correlated with molecular structure, showing that the nature of the donor substituents and molecular architecture influence charge-transfer efficiency, trap distribution, and, ultimately, multilevel memory performance. These findings represent a significant advancement in the development of organic high-density storage memory devices.

Zr₃C₂O₂ MXene has garnered extensive interest as an anode material for alkali-ion batteries. Nevertheless, its inferior electrochemical performance compared to the well-established Ti- and V-based MXenes calls for targeted strategies to unlock its full potential. Heteroatom doping with nonmetals offers an effective way to overcome these limitations by tuning the electronic structure and surface chemistry while keeping the MXene framework intact. Herein, first-principles density functional theory calculations are used to systematically investigate nitrogen (N) and sulfur (S) substitution at the carbon site of Zr₃C₂O₂ MXene. The effects of doping on its structural, electronic, and electrochemical properties as an anode for lithium-ion batteries (LIBs) and sodium-ion batteries (NIBs) are examined. Three doping strategies were considered: N mono-doping, S mono-doping, and N–S co-doping. We evaluate each of these strategies for a range of dopant concentrations from single atom substitution to full site occupation within the supercell. Such a systematic study allows us to probe the isolated defect behavior at low concentrations and the dopant–dopant interaction and collective electronic modulation at higher doping levels. The calculations confirm that substitution at the carbon site is energetically favorable for both heteroatoms. N-doped systems consistently outperform S-doped and N–S co-doped counterparts in terms of structural stability, metallicity, and electrochemical response. N–S co-doping shows synergistic improvements than S doping. The 12N-substituted Zr₃C₂O₂ exhibits the best performance with the highest density of states at the Fermi level, favorable Li/Na adsorption energetics, the lowest average open-circuit voltage, and reduced ion diffusion barriers among all the configurations. Theoretical specific capacities of 328 mA h g^–1 for LIBs and 283 mA h g^–1 for NIBs are achieved. These findings demonstrate that controlled heteroatom substitution is an effective design strategy for simultaneously optimizing structural integrity, electronic conductivity, energy density, and ion storage capacity in MXene-based anodes for next-generation alkali-ion batteries.

Measuring absolute magnetic fields with high precision is valuable for numerous scientific and technological applications, including physics research, biomedical imaging, navigation systems, and materials characterization. Two-dimensional (2D) vdW materials, with their characteristic weak interlayer (van der Waals) bonding, are well suited for transfer onto a diverse range of substrates, making them amenable to a variety of sensing platforms. In this article, we explored the potential of CrCl₃, a 2D vdW magnetic material, for application in a compact, laser-free absolute magnetometer. We found that the proposed CrCl₃-based magnetometer provides electrical detection of the absolute magnetic field with nanotesla sensitivity, features a simple, compact design, and a small form factor, demonstrating a clear, attractive technology pathway. The sensor material is fabricated using Scotch tape-based room-temperature mechanical exfoliation processes, operates over a wide magnetic field and temperature range, and is robust at ambient conditions. The demonstrated magnetometer's sensitivity is ∼30 nT/√Hz at a 1 T applied magnetic field, and it can track magnetic field changes in real time at a rate exceeding 0.8 mT/s.