ACS Applied Electronic Materials最新文献

Here, we have effectively created a 2-dimensional rGO-based carbon composite material that is embellished with one-dimensional carbon nanotubes (CNTs). The phase composition and hierarchical structure of the composites are greatly altered by the addition of CNTs in the rGO. This leads to a multidimensional gradient, defects, diverse contacts, and hence improved microwave absorption capabilities. The composite exhibits a top-notch microwave absorption efficiency: RL_max for the composite GC 10 wt %, −42.03 dB of loss with an effective absorption bandwidth (EAB) of 1.36 GHz, and an EAB of 3.84 GHz at a thickness of 1.9 mm. While covering the whole X and Ku bands within a thickness range from 1.9 to 3.2 mm, the RL_max for GC 12.5 wt % loading is −59.8 dB, with an EAB of 3.52 GHz at a thickness of 2 mm. This composition covers the whole X and Ku bands within a thickness range from 1.5 to 3 mm. We demonstrate that the GC has the most noticeable transient coexistence of nanotube and sheet structures, which enhances the conduction loss mechanism and interfacial polarization. So, the rGO/CNT-based porous carbon composite has a lot of potential for next-generation applications, including stealth coatings and advanced communication devices.

The exploration of MXenes for electronic applications is a rapidly growing field in materials science. However, most research has focused on MXene films, with only a limited number of studies addressing the characterization of single-flake devices. In this work, we investigate the electronic and magnetotransport properties of Ti₃C₂T_x single-flake devices, exploring the influence of structural defectivity on their transport mechanisms. We show that negative magnetoresistance present at low temperatures in single flake samples arises from weak localization, which we analyze to extract the phase coherence length of single-layer and multi-layer flakes. The study of magnetoresistance for this metallic MXene shows that the material exhibits quantum transport phenomena when intrinsic electronic behavior dominates. Moreover, by increasing the defect density via thermal annealing in ultrahigh vacuum, we uncover and characterize the metal-to-disordered metal transition in Ti₃C₂T_x, shedding light on new properties and enriching fundamental knowledge about MXenes.

The pursuit of balanced performance encompassing high sensitivity, a broad detection range, and excellent durability remains a core challenge for the practical application of flexible piezoresistive sensors. This study reports a sandwich-structured flexible piezoresistive sensor, which utilizes a carbonized reduced graphene oxide film (C-rGOF) as the core sensing material and is encapsulated with polydimethylsiloxane (PDMS, denoted as C-rGOF@PDMS). The sensor is fabricated via a hydrazine hydrate-assisted gradient foaming strategy combined with high-temperature carbonization, resulting in a C-rGOF sensing core with a uniform and stable 3D porous structure. The device achieves a combination of key performance metrics: a high sensitivity of up to 122 kPa^–1, a broad detection range of 0.01–1300 kPa, a fast response/recovery time of 70/52 ms, an ultralow detection limit of 100 mg, and stable cyclic performance exceeding 40,000 cycles at 1 kPa. Thanks to these properties, the sensor accurately captures a wide spectrum of human motions, including subtle physiological activities such as frowning and swallowing to dynamic joint movements including those of the elbow and knee. By integrating a 4 × 4 sensor array and implementing a column-by-column scanning circuit strategy, signal crosstalk was effectively suppressed, enabling dynamic spatial pressure mapping. Furthermore, an integrated tactile glove system centered around an Arduino controller was developed, which successfully translated common hand gestures, including numerals 1 through 5, a finger-heart gesture, and fist clenching, into stable and precise control of a bionic robotic hand. This work, which progresses from material design to system integration, provides a paradigm for constructing high-performance, low-cost, and scalable flexible tactile systems, with potential for applications in medical rehabilitation, intelligent prosthetics, and remote manipulation.

Secure optical communication requires photodetectors that are fast, broadband, bidirectional, and stable. Traditional devices often face issues like narrow spectral response, unidirectional operation, and poor durability. We present a bidirectional transient organic photodetector (T-OPD) for aerial and underwater self-powered applications, structured as ITO/PEDOT:PSS/Active layer/Ionic liquid gel (IL)/ITO. Both the top (ITO/IL) and the bottom electrodes (ITO/PEDOT:PSS) exhibited an average transparency of 80–85% across the entire UV–vis-NIR spectrum (400–940 nm), allowing the devices to operate bidirectionally. Using a blend of polymer donor PM6 and nonfullerene acceptor Y6, it detects broadband from UV to NIR (940 nm). The ultrathin layer of IL gel provides water resistance and also induces a nanoscale interfacial electric double layer (EDL), which enhances charge separation and sensitivity without external bias, maintaining stability during 168 h of unencapsulated self-powered operation underwater immersion. The device has fast response times (30 and 47 μs) and a high cutoff frequency (∼187 kHz). Exploiting these features, we demonstrate a self-powered secure aerial and underwater bidirectional communication system, where one wavelength channel transmits the primary data and another provides encryption. Stable optical signal transmission through a water channel and clear waveform recovery highlight the device’s robustness as a promising technology for secure communication, with applications in naval operations, diver-to-surface communication, aircraft-to-sea transmissions, and marine IoT networks.

The transition-metal chalcogenide (TMC) family of materials has proven to be fruitful for applications of low-dimensional crystals and films. While the devices based on them usually require sophisticated production procedures combined with precisely controlled environments and high-resolution lithography, we propose a much simpler and more versatile approach. Here we demonstrate how Zr_1–xTi_xS₃ solid solution crystals produced by the chemical vapor transport technique could be easily used for fast, high-response, and robust humidity sensors in all of the available measurement ranges. This material has a monoclinic crystalline structure with a P2₁/m space group and crystallizes in high surface area, thin, and long sword-like or necktie ribbons. Brief ultrasound treatment in 2-propanol produces an ink that could be used on any kind of substrate, including flexible ones, by drop-casting. We show a sensitivity to water vapor with R/R₀ higher than 1000 times with a fast response rate close to 100 ms and low recovery times shorter than 0.95 s. The sensors produced in such a manner are stable in ambient air and do not require specific storage conditions.

Accurate acquisition of weak electrophysiological signals such as electrocardiography (ECG), electroencephalography (EEG), and electrooculography (EOG) is critical for healthcare monitoring yet remains technically challenging because electrophysiological signals exhibit inherently low amplitudes, narrow bandwidths, and high susceptibility to external interference. Organic electrochemical transistors (OECTs), with their high transconductance (g_m) and low-voltage operation, offer a promising platform for electrophysiological signal amplification. Herein, we develop high-performance vertical OECTs (vOECTs) based on poly(3,4-ethylenedioxythiophene):polystyrenesulfonate/poly(vinyl alcohol) (PEDOT:PSS/PVA) blends for multimodal electrophysiological signal acquisition. The introduction of PVA effectively tailors the microstructure and enhances ion-electron transport, yielding a peak g_m of 113 mS and sub-3 ms response time. The devices exhibit linear amplification of sinusoidal signals across a broad physiological frequency range and maintain the waveform and temporal fidelity of ECG, EEG, and EOG waveforms with minimal distortion. Compared to previously reported OECTs, the vOECTs achieve 23-fold to 450-fold gain enhancements. These results demonstrate a scalable and high-fidelity signal amplification strategy, paving the way for next-generation wearable bioelectronic systems.

Layered magnetic transition-metal chalcogenides (TMCs) are a focal point of research, revealing a variety of intriguing magnetic and topological ground states. Within this family of TMCs, chromium telluride has garnered significant attention because of its excellent tunability in magnetic response, owing to the presence of competing magnetic exchange interactions. We here demonstrate the manipulation of magnetic anisotropy in ultrathin Cr₂Te₃ films through growth engineering leading to a controlled transition from in-plane to out-of-plane orientation with an intermediate noncoplanar magnetic ground phase characterized by a topological Hall effect. Moreover, interfacing these films with vanadyl phthalocyanine (VOPc) molecules prominently enhances the noncoplanar magnetic phase, attributing its presence to the competing interfacial magnetic exchange interactions over the spin–orbit-driven interfacial effects. These findings pave the way for the realization of novel topological spintronic devices through interface-modulated exchange coupling.

The development of electronic nose systems is an important but rather challenging task nowadays. Organic field-effect transistors provide a powerful platform that is promising for electronic nose creation. In this work the sensory properties of a recently synthesized series of siloxane dimers of benzothieno[3,2-b][1]benzothiophene (BTBT) with different terminal alkyl groups (D2-Und-BTBT-Alkyl) as well as the possible mechanism of their sensitivity were investigated in detail. It was found that in spite of very similar chemical structure the dimers demonstrated dissimilar sensitivity and selectivity to various analytes─H₂S, NH₃, SO₂, NO₂, and several volatile organic compounds. The proposed mechanism of the patterns observed depends on both the correlations between the HOMO/LUMO energy levels of the dimer and the analyte and the dimer layer morphology/molecular packing. PCA analysis allowed us to choose the best four OFETs based on different siloxane dimers without any receptor layer for separation of the analytes and determining their concentrations on a 2D plot. These findings demonstrate that a rather small difference in the chemical structure of the organic semiconducting materials used for the OFET fabrication makes it possible to apply them as an array for the electronic nose creation.

Conjugated polymers based on diketopyrrolopyrrole (DPP) and thiazolothiazole were synthesized from dialdehyde DPP and dithiooxamide via Schiff-base condensation and cyclization. The reaction utilizes only monomers and solvent, proceeding without any catalyst. The optical properties, molecular orbital energy levels, and microstructures were systematically investigated. Moreover, the synthesized conjugated polymers were evaluated as active layers in organic field-effect transistors, exhibiting a hole mobility of 0.06 cm² V^–1 s^–1 with an I_on/I_off ratio of 10⁵. This work demonstrates that the Schiff-base condensation and cyclization approach has environmentally friendly characteristics and is applicable to the green synthesis of conjugated polymers.