ACS Applied Electronic Materials最新文献

Accurate humidity monitoring is crucial in numerous application fields, and developing humidity sensors that combine high sensitivity, fast response, wide-range detection, and long-term stability is of great significance. This work constructs a composite gel humidity-sensitive material (SCR&Br) with a semi-interpenetrating conductive network by introducing cellulose nanocrystals/reduced graphene oxide (CNCs/rGO) nanohybrid material with 1-ethyl-3-methylimidazolium bromide (EMIMBr) into a sodium alginate (SA) matrix. Based on the synergistic effect of organic and inorganic components, the material synergizes the porous hydrophilic characteristics of the organic phase with the electronic/ionic conductivity of the inorganic component to construct a gel-based sensing network for ion–electron cooperative transport. Further adopting the electrohydrodynamic (EHD) printing method to achieve controlled molding of the moisture-sensitive coatings, combined with the freeze-drying process, the porous SCR&Br humidity sensor was fabricated. By adjusting the proportions of each component, the fabricated SCR&Br sensor exhibits low humidity hysteresis (≤4.6%), fast response (∼6 s), and speed recovery (∼48 s), as well as good long-term stability (≥67 days) within the 11–95% relative humidity (RH) range. Such sensors are scalable and suitable for daily environmental humidity detection, indicating that high-performance humidity sensors based on low-cost organic–inorganic composite materials are emerging as effective candidates for environmental monitoring technologies.

The natural polymer chitosan has gained much attention from researchers in the areas of tissue engineering and wound healing because of its biodegradability, antimicrobial activity, and piezoelectric properties, which could help improve cell growth and accelerate wound healing. Moreover, it has biocompatible and environmentally friendly properties, which are suitable for the development of sensors for medical applications. This study aims to fabricate a sensor using a natural polymer chitosan solution with glycine and nontoxic solvents as a matrix. The near-field electrospinning (NFES) technique was adopted for the preparation of well-aligned fibers. We focused on investigating the mechanical, piezoelectric, and biodegradable properties while analyzing the relationship between the process parameters and the composite solution (1–7 wt %) while adding glycine, which improves the piezoelectric properties of the composite fibers. Laser scanning confocal microscopy was used to observe the morphology of the fibers, and X-ray diffraction (XRD)/Fourier-transform infrared spectroscopy (FTIR) was also used to characterize the crystal phase and quantify the structure of the chemical material. The electrospun fibers had a consistent morphology, a high surface area-to-volume ratio, and inter/inner porosity. Finally, a uniform design and optimization tools are used to obtain the optimal spinning parameters. The piezoelectric voltage can be increased from 61.6 to 72.0 mV (∼16.9%), and the sensitivity is 2.6 mV/N. These sensors can be applied in regenerative medicine for electrical stimulation repair and preventive medicine for healthcare.

Polypropylene (PP) has emerged as a promising candidate for cable insulation in high-voltage direct-current (HVDC) transmission systems due to its high working temperature and exceptional electrical properties. Through ethylene sequence engineering, the crystallization behavior of PP is modulated by strategically incorporating ethylene comonomer units into the polymer backbone, thereby tailoring the crystalline morphology and reducing spherulite dimensions to optimize dielectric performance. The controlled distribution of ethylene segments disrupts long-range chain ordering, refining the crystalline–amorphous interface and suppressing space charge accumulation. At 90 °C, the average DC breakdown strength of PPR was enhanced by 25 and 28% compared to PPH and PPB, respectively. This significant improvement is attributed to the semicrystalline microstructure resulting from ethylene sequence engineering. These findings provide a molecular-level design strategy for high-voltage insulating materials, balancing crystalline morphology control and dielectric properties.

This work describes the fabrication of an electrochemical sensor constructed upon La-doped Dy₂O₃ and multiwalled carbon nanotube (MWCNT) composite for the sensitive and selective detection of N-methyl-p-aminophenol sulfate (metol, MTL), a representative aromatic pollutant of environmental and toxicological relevance. The La-Dy₂O₃/MWCNT nanocomposite was synthesized via a hydrothermal method and the structural, morphological, and compositional properties were systematically investigated through scanning electron microscopy–energy dispersive X-ray spectroscopy (SEM-EDX), X-ray photoelectron spectroscopy (XPS), attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR), and X-ray powder diffraction (XRPD). Electrochemical evaluation by cyclic voltammetry (CV), square-wave voltammetry (SWV), and electrochemical impedance spectroscopy (EIS) confirmed the superior electrocatalytic performance of the composite-modified glassy carbon electrode (GCE), arising from the synergistic effects of La³⁺ doping and the high electrical conductivity of the MWCNT network. Periodic density functional theory (DFT) calculations were employed to investigate dopant-induced modifications in the bulk electronic structure, while molecular DFT provided insight into the redox behavior of MTL underlying the observed electrochemical response. The sensor exhibited a wide linear response range (0.3–220 μM), a low detection limit of 0.1 μM, and high sensitivity (0.387 μA μM^–1 cm^–2), with kinetic analyses indicating a diffusion-controlled, proton-coupled electron transfer mechanism and optimal performance at pH 7.0. Furthermore, the sensor demonstrated excellent reproducibility (RSD = 3.06%), repeatability (RSD = 3.35%), and operational stability over 15 days, along with strong anti-interference capability and high recovery values in complex matrices, including tap water, river water, artificial urine, and human serum, without the need for pretreatment or sophisticated instrumentation, highlighting its potential as a reliable, field-deployable, and cost-effective platform for environmental and clinical monitoring of electroactive aromatic contaminants.

This work demonstrates the synthesis of spin-on oxide semiconductors via an ultraviolet (UV)-assisted annealing process using metal–organic precursors with β-diketone ligands. This process promotes the decomposition and subsequent condensation while preserving a high density of hydrogen- and oxygen-related donor species. These donors effectively supply free electrons and fill shallow trap states near the conduction band minimum (CBM), resulting in enhanced carrier mobility and on-current. A peak field-effect mobility of 89 cm²/V·s, an on-current (I_on) of 26.42 μA, and an I_on/I_off ratio of 10⁸ were achieved in bottom-gated transistors using a SiO₂ gate dielectric. Moreover, the high density of trap states near the CBM broadens the spectral detection range from UV to visible light, yielding a high responsivity of 8,900 A/W and a detectivity of 1.26 × 10¹⁴ Jones. Leveraging this broadband photoresponsivity, we further developed a vertically stacked sensor platform for the detection of volatile organic compounds (VOCs). These results highlight UV-assisted solution processing as a powerful strategy to realize high-performance oxide electronics and multifunctional sensor platforms.

While 2D materials possess exceptional properties, their practical use remains limited by a critical gap: the lack of scalable manufacturing methods to bridge laboratory synthesis and industrial production. Here, we propose a “mineral-to-device” workflow that combines electrochemical exfoliation (ECE) and laser processing to create robust, flexible, and implantable electronics directly from natural minerals. We call this the “Ink and Pen” concept: it starts with a green, scalable ECE process to yield high-quality, diazonium-functionalized graphene inks (“The Ink”) and uses laser processing (“The Pen”) as a maskless tool to pattern and integrate these materials onto polymers and ceramic-coated titanium. To demonstrate the versatility of this approach, we fabricated mechanically robust circuits, multimodal sensors, and biocompatible electronics for medical implants that function reliably under physiological conditions. This technology offers a sustainable pathway for using diverse 2D minerals, paving the way for next-generation smart systems ranging from healthcare wearables to the Internet of Everything.

Solution-processed SnO₂-based thin-film transistors (TFTs) have attracted significant attention due to their low cost, low toxicity, and the high abundance of SnO₂. However, SnO₂-TFTs suffer from large negative threshold voltage as well as low on/off ratios because of high residual carrier electrons from oxygen vacancies. It is known that doping elements, such as Si, that form strong chemical bonding with oxygen suppresses oxygen vacancy formation. Here, we fabricated and characterized Si-doped SnO₂ (Si_xSn_yO) TFTs. In Si_xSn_yO-TFTs, we found that increasing the Sn molarity leads to an enhancement in field-effect mobility while inducing a negative threshold voltage shift. To clarify the origin of this mechanism, we measured the effective channel thickness of Si_xSn_yO-TFTs by electric field thermopower modulation analyses. The effective mass (m*) of the Si_xSn_yO films slightly decreased with increasing Sn molarity and was approximately 0.15 m₀, suggesting that an increase in Sn molarity improves the metal–oxygen network in the film. The effective channel thickness, which corresponds to the accumulation layer thickness, increased with rising sheet carrier concentration at low Sn molarity. On the other hand, it decreased with increasing sheet carrier concentration at high Sn molarity. This suggests that the carrier transport mechanism varies depending on Sn molarity. These findings provide guidance in developing high-mobility and reliable Si_xSn_yO-TFTs through appropriate control of the Sn molarity in Si_xSn_yO.

Printed organic electrochemical transistors (OECTs) are promising for flexible bioelectronics due to their low operating voltage, high transconductance, and mechanical flexibility, which enable seamless integration with soft biological tissues. However, printed planar-channel OECTs typically suffer from a slow transient response, mainly owing to the printing resolution, which restricts their use in high-speed logic circuits and high-throughput sensing. This work presents all screen-printed vertical step OECTs (VS-OECTs) on a flexible substrate, using poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) as a channel material, poly(sodium 4-styrenesulfonate) (PSSNa)-based conductive hydrogel as an electrolyte, and Ag/AgCl paste as a top gate. In this vertical design, the source and drain electrodes are separated by an insulating layer, forming a vertical step structure. This vertical structure offers advantages over conventional planar-channel structures, where higher source-drain current I_ds (∼0.45 mA), higher transconductance g_m (∼1 mS), higher ON/OFF ratio (2.6 × 10⁴), faster switching time (1.27 ms to turn on and 8.4 ms to turn off), and better pulsing stability (>96% after 1000 gate pulse) can be attained. Bending tests and various substrate printing validate the flexibility and universal printability of the vertical structures. Additionally, a unipolar inverter based on printed VS-OECTs operates at a high frequency (∼100 Hz), and effective signal amplification for electrocardiogram (ECG) and wrist artery pulse monitoring has been demonstrated, highlighting the potential of printed VS-OECTs for personal health monitoring. These findings propose a promising approach for producing large-area and high-performance printed OECTs, paving the way for the development of all-printed transistors with fast response times for various applications.

Developing high-performance and practical graphene-based field emission materials remains a significant challenge, primarily due to the difficulty in balancing the density of emission sites with structural stability. Herein, we designed a Ni–Mo bimetallic interlayer to achieve the in situ growth of multilayer graphene (MLG) on microscale silicon tip arrays via radio frequency plasma-enhanced chemical vapor deposition (RF-PECVD). This approach leverages MEMS-fabricated microtip arrays to provide strong field enhancement. Meanwhile, the Ni–Mo bimetallic interlayer induces periodically corrugated MLG through the Kirkendall effect. To clarify the underlying mechanism, we developed an MLG growth model to describe the chemical reactions during deposition. We also derived a texture evolution model based on the Kirkendall effect. Furthermore, the defect density of the MLG can be precisely controlled by adjusting the growth temperature. Our results show that the composite cathode achieves optimal field emission performance when I_D/I_G in the Raman spectrum is approximately 0.33. The composite cathode MLG/Ni–Mo/Si-tip exhibited low turn-on field (E₀ = 2.72 V/μm), a high current density (J_max = 25 mA/cm² at 5.78 V/μm), a large field enhancement factor (β) of ∼2121 at a growth temperature of 750 °C. In comparison, the MLG/Ni/Si-tip group exhibits an optimal turn-on field of 3.93 V/μm. These results demonstrate that the proposed design effectively integrates the field-enhancement advantages of microtip cathodes with the superior emission capabilities of two-dimensional (2D) graphene. This approach provides a meaningful synergistic strategy, combining structural and material optimizations to improve graphene-based field emitters.