ACS Applied Electronic Materials最新文献

Ferroelectrics enable large charge doping of two-dimensional overlayers, but the coexistence of switching and nonswitching charge dynamics complicate electro-optical analysis. Here, we investigate the optoelectronic response of a ferroelectric/graphene device under 365 and 530 nm illumination, disentangling effects on ferroelectric dipole alignment from extrinsic current pathways. Graphene acts as a high-gain sensor, amplifying subtle polarization dynamics into a pronounced resistance difference. By resolving switching and nonswitching channels in dark and illuminated conditions, we reveal a competition between photovoltaic charge screening and defect-assisted excitation that governs device electrostatics. Above-band gap illumination generates free carriers that induce leaky ferroelectric hysteresis and suppress the graphene resistance ratio between opposite remanent polarization states from 290% to 15% due to dynamic photovoltaic charge screening. In contrast, 530 nm illumination primarily induces charge redistribution in ferroelectrics via defect-state excitation, leading to a significantly weaker suppression of the resistance variation of graphene. These results establish practical guidelines for selecting photon energy and intensity to either preserve remanent polarization while tuning channel doping or deliberately reconfigure polarization through optical programming.

Multifunctional flexible electronic sensors are highly demanded since single-function variants fail to satisfy portable/wearable electronics’ complex and growing requirements. Currently fabricated via multistep integration of single-function sensors, developing a single multifunctional sensing material remains challenging. In this study, Sn-doped MoO₃ (Sn_xMo_1–xO₃) nanobelts were fabricated into a dual-mode sensor for ethanol gas and temperature detection. The Sn_0.05Mo_0.95O₃ sensor detected ethanol at an ultralow concentration of 0.1 ppm at room temperature. Its response to 10 ppm of ethanol was 2.1 times higher than that of pure MoO₃ sensor. In addition, the Sn_0.05Mo_0.95O₃ temperature sensor demonstrated a negative temperature coefficient of resistance (TRC) of −0.0183 °C^–1, an 8-fold improvement over pure MoO₃. The enhanced sensing performance of Sn doping can be ascribed to four key factors: a narrowed band gap, reduced adsorption energy, increased charge transfer, and an accelerated electron transfer rate. This research provides a highly efficient sensing material with promising practical applications for dual-mode ethanol and temperature detection.

The integration of wafer-scale two-dimensional (2D) materials, such as graphene, onto device wafers remains a significant challenge for practical applications due to persistent issues of transfer-induced defects, including polymer-residue contamination and film cracks. Here, we demonstrate a van der Waals assembly technique that achieves a damage-free transfer of graphene by simultaneously modulating interfacial hydrophobicity and electrostatic charge distribution. This approach eliminates the need for polymer carriers, thereby preserving the intrinsic properties of graphene. The electrostatic conformal adhesion between copper-grown graphene and the target substrates ensures surface cleanliness and structural integrity. The intercalation of the etchant solution at the graphene-substrate interface is effectively prevented by the hydrophobic interface, which ensures direct interfacial contact and maintains the structural integrity. The transferred graphene films exhibited 99.7 ± 0.3% coverage, subnanometer root-mean-square roughness of 0.697 nm, and room-temperature field-effect mobility up to 6651 cm²·V^–1·s^–1. This technique is applicable to various substrates, including SiO₂/Si, polyethylene terephthalate (PET), polyvinyl chloride (PVC), quartz, and sapphire, and is compatible with standard semiconductor manufacturing processes. Consequently, this transfer approach provides a scalable pathway for the fabrication of graphene-based devices.

Perovskite light-emitting diodes exhibit great potential in the fields of display and lighting, yet their performance is still limited by interfacial nonradiative recombination and charge imbalance. Although alkali metal compounds (AMCs) have been extensively studied as perovskite lattice components or bulk dopants, the strategy of using AMCs as functional interlayers or interfacial modifiers has received far less attention than it deserves. Despite the fact that this strategy has been proven effective, there is still a lack of systematic sorting and review of its multidimensional action mechanisms. We aim to fill this gap and explore the multiple interfacial roles of AMCs. This review not only provides a perspective for understanding the interfacial physicochemical processes related to AMCs, but also offers theoretical insights for the design and fabrication of high-performance and stable device.

Neuromorphic computing, inspired by the brain, has emerged as a potential approach to overcome the current von Neumann bottleneck. Herein, a transparent and integrable ZnO/In₂O₃ heterojunction crossbar artificial synapse was fabricated using magnetron sputtering for neuromorphic computing. The resistive switching behavior of the device originates from the regulated migration of oxygen vacancies within the heterojunction under an applied electric field. Moreover, the fabricated artificial synapse exhibited exceptional stability, with its resistive switching characteristics remaining unchanged after six months of exposure to ambient conditions. The device demonstrates typical synaptic behavior, including paired-pulse facilitation (PPF), short-term to long-term memory transitions, spike-timing-dependent plasticity (STDP), potentiation/depression, and learning–forgetting processes. Furthermore, the fabricated device-based reservoir computing enabled efficient temporal information processing, and an artificial neural network (ANN) incorporating the device’s synaptic achieved 92.37% recognition accuracy of the MINIST database. Besides, in combination with MATLAB, basic digital logic circuits such as OR, AND, XOR, and XNOR were successfully implemented. Based on this, a half-adder and a parity checker were further constructed to achieve the encryption and decryption of information. This work demonstrates the feasibility of ZnO-based heterojunction memristors to develop multifunctional electronic devices for neuromorphic computing and logical operation applications.

Developing sustainable and flexible materials that can efficiently convert mechanical stimuli into electrical signals remains a key challenge in soft electronics. In this work, we demonstrate a Zeta-fold structured paper-based composite composed of α-cellulose fibers and carbon black that exhibits mechanically amplified conductivity and pressure-dependent electrical response. The folded configuration forms a hierarchical contact–separation interface, which redistributes stress and reconstructs conductive networks under compression. This design enhances the electromechanical coupling, giving a high sensitivity of 0.12 kPa^–1, a low detection limit of 20 Pa, and fast response and recovery times of 100 and 80 ms, respectively. The composite shows excellent stability over 1000 cycles and consistent performance during human-motion and logic-signal detection. The Zeta-fold approach offers a simple and environmentally friendly route to integrate structural mechanics with electronic functionality, suggesting broad potential for sustainable and flexible electronic systems.

We demonstrate a monolithic gas sensor array that integrates p-type Cu₂O and n-type a-IGZO films via a UV-assisted precursor patterning method, eliminating the need for etching or development steps. This bidirectional configuration enables p- and n-type sensors to exhibit opposite resistance changes toward the same gas, providing deep learning models with an additional discriminative dimension. The sensor array was evaluated using four representative target gases: ozone (O₃), nitrogen dioxide (NO₂), hydrogen peroxide (H₂O₂), and nitrogen monoxide (NO), which include both inorganic oxidizing species and volatile organic compounds. A neural network trained on full resistance–time profiles achieved classification accuracies above 95%, significantly outperforming traditional machine learning algorithms such as support vector machine (76%), random forest (69%), and naïve bayes (50%). Compared to arrays with only a-IGZO sensors (68% accuracy), the inclusion of Cu₂O/a-IGZO heterojunctions improved accuracy by over 25%. The system also achieved high-precision gas concentration prediction (R² > 0.98) and demonstrated excellent humidity tolerance via baseline correction. This scalable, lithography-free strategy offers strong potential for compact and high-selectivity gas sensing systems suitable for portable and real-world environmental monitoring applications.

Aqueous ammonium-ion batteries (AAIBs) are attracting increasing interest because of the abundance and low cost of ammonium salts and the inherent safety of aqueous electrolytes. However, the development of AAIB anodes remains limited, and many reported anodes suffer from rapid capacity fading and unstable Coulombic efficiency, often associated with strong hydrogen-bonding effects. Here, we report the first cobalt–ammonium hybrid battery consisting of a metallic Co anode, a mixed CoSO₄/(NH₄)₂SO₄ aqueous electrolyte, and an Fe[Fe(CN)₆] (FeHCF) cathode. The battery operates via coupled NH₄⁺ insertion/extraction at the cathode and Co plating/stripping at the anode. In three-electrode tests, the optimized FeHCF/multiwalled carbon nanotube (FeHCF/MWCNT) composite cathode delivers 94 mAh g^–1 at 0.2 A g^–1 and retains 78.5% of its capacity with ∼100% Coulombic efficiency after 1000 cycles at 0.8 A g^–1. The full cell achieves 112 mAh g^–1 and 88 Wh kg^–1 at 0.2 A g^–1, maintaining 90% capacity with ∼100% Coulombic efficiency after 1000 cycles at 0.8 A g^–1. A quasi-solid-state device further demonstrates 73 mAh g^–1 at 0.2 A g^–1 and stable cycling over 1000 cycles. These results demonstrate the feasibility of cobalt–ammonium hybrid chemistry for safe and durable aqueous energy storage.

The roles of nanostructured materials are crucial for monitoring and quantifying emerging environmental contaminants that pose serious ecological and health risks. This study reports the bioinspired synthesis of 2D vertically aligned ZnO nanostructures onto fluorine-doped tin oxide glass using Sechium edule (SE) fruit extract and its functionalization with carbon quantum dots (CQDs-ZnOVANs(bio)/FTO) fabricated using carbon-rich remnant peel. The functionalized platform was tested for electrocatalytic monitoring of norfloxacin (NFX) in environmental matrices. ZnOVANs(bio)/FTO modified with CQDs at an immersion time of 1.5 min (CQDs_1.5-ZnOVANs(bio)/FTO) oriented vertically with an average length of 965.3 nm and a thickness of 46.3 nm with high crystallinity. The average particle size of CQDs was 4.7 nm with an amorphous nature. CQDs_1.5-ZnOVANs(bio)/FTO exhibited 2.6- and 2.7-fold enhancement in anodic current density and electroactive area (A_e), respectively, along with a 34.6% decrement in charge transfer resistance (R_p) compared to ZnOVANs(bio)/FTO. NFX monitoring at CQDs_1.5-ZnOVANs(bio)/FTO took place in a two-electron and two-proton transfer process with a E⁰ of 1.042 V, rate constant (k⁰) of 0.105 s^–1, and surface coverage by NFX ions (Γ*) of 2.54 × 10^–11 mol cm^–2. CQDs_1.5-ZnOVANs(bio)/FTO exhibited a detection limit of 0.0066 μM and sensitivity of 0.1903 μA μM^–1 cm^–2 within 0.25–40 μM NFX. The developed electrode exhibited excellent stability with only 8.1% reduction in anodic peak current up to the 15th reuse cycle of the same sensing platform. The common antibiotics, including ciprofloxacin, phenylbutazone, sulfamethoxazole, chloramphenicol, chloroquine, and furazolidone, could not interfere with the NFX monitoring. CQDs_1.5-ZnOVANs(bio)/FTO could effectively monitor and quantify NFX spiked in environmental samples, and the results are comparable to liquid chromatography.

Two-dimensional (2D) van der Waals contacts between metals and semiconductors offer a promising route to mitigate Fermi-level pinning (FLP) and metal-induced gap states (MIGS) in field-effect transistors (FETs). However, the Schottky barrier and tunneling barrier seriously degrade device performance, limited by the work functions and surface properties of 2D layered metals. Herein, we propose an interfacial engineering strategy to modulate the contact properties of MXene/TeO₂ heterostructures by tailoring surface terminations (–O, –F, −OH) of MXene electrodes via first-principles calculations. We demonstrate that OH-terminated MXenes form strong hydrogen bonds with TeO₂, effectively narrowing the van der Waals gap and enhancing the electron tunneling probability. Notably, OH-terminated MXenes achieve n-type Ohmic contacts at both vertical and lateral interfaces. This work provides a feasible approach for designing high-performance 2D electronic devices with optimized interfacial properties.