ACS Applied Electronic Materials最新文献

Supercapacitors (SCs) differ significantly from batteries due to their superior electrochemical performance. Metal–organic framework (MOF)-based electrodes exhibit promise for use in energy storage systems, and their possible implementations have been reported. In this research work, we employ a two-step hydro/co-precipitation method to synthesize different types of metal oxide-based nanocomposite electrode materials, including C-LH, FC-LDH, and CFC-LTH. Additionally, CFC-LTH@MOF is prepared, and its electrochemical activity is studied. Trimetallic (Co, Fe, and Ce) CFC-LTH@MOF positive electrodes are prepared on nickel foam, which is utilized as a substrate due to its high conductivity, by the hydrothermal synthesis method. Furthermore, the synthesis parameters were optimized to achieve the desired hierarchical morphology, thereby enhancing the electrochemical performance of CFC-LTH@MOF composites. The CFC-LTH@MOF electrode revealed a high areal/specific capacitance of 1.76 μAh cm²/2120.8 F g^–1 at a current density of 4 mA/cm², which was about 1.4 times higher than that of CFC-LTH (1.47 μAh cm²/2008 F g^–1), followed by FC-LDH (1.2 μAh cm²/1175.2 F g^–1) and C-LH (0.7 μAh cm²/887.2 F g^–1). Additionally, their structural, spectral, morphological, and crystalline properties, as well as their chemical states and surface features, were studied through appropriate characterization techniques. An asymmetric hybrid supercapacitor (HSC) device was successfully fabricated, and its electrochemical performance was evaluated through cyclic voltammetry (CV) and GCD analyses within a potential window of 1.6 V. The as-fabricated assembled coin cell HSC exhibits exceptional electrochemical characteristics, including outstanding cycling stability (10k cycles) and increased rate capability (96.5%). The obtained results demonstrate the improved electrochemical performance of the prepared nanocomposite electrode material, CFC-LTH@MOF-based HSCs which have high energy densities and are suitable for advanced SC applications.

Electrospun poly(vinylidene fluoride) (PVDF) nanofibers are promising for flexible self-powered sensing, but controlling the electroactive crystalline phase while maintaining suitable morphology and mechanical integrity remains challenging. Here, amino-functionalized reduced graphene oxide (NH₂-rGO) was incorporated into electrospun PVDF nanofibers to regulate crystalline structure and triboelectric sensing performance. NH₂-rGO promoted β-phase formation, with the highest Fourier transform infrared (FTIR)-derived β-phase fraction of 81.6% obtained at 3 wt % loading. This phase evolution results from the combined effects of electrospinning-induced molecular orientation and NH₂-rGO-mediated interfacial interactions. Frequency-dependent dielectric measurements further showed that NH₂-rGO enhanced the dielectric response and interfacial polarization of the composite membranes. Considering β-phase fraction, crystallinity, dielectric response, fiber morphology, filler dispersion, and mechanical properties, the PVDF/3 wt % NH₂-rGO membrane provided the best overall balance and was selected for sensing. The resulting self-powered triboelectric sensor generated reproducible signals under different mechanical stimuli, enabled real-time monitoring of plantar, knee, and elbow motions, and maintained stable responses over 3000 cycles. These results demonstrate a practical strategy for developing flexible PVDF-based wearable motion sensors without relying on external power supplies and with good cyclic repeatability for wearable applications.

The rapid growth in artificial intelligence and large-scale data processing has driven the urgent demand for energy-efficient electronic devices. Ferroelectric materials, especially hafnium zirconium oxide (Hf_0.5Zr_0.5O₂, HZO), have emerged as promising candidates due to their inherent nonvolatile polarization and complementary metal–oxide–semiconductor compatibility at nanoscale thicknesses. However, conventional high-temperature annealing (>400 °C) limits integration with temperature-sensitive and two-dimensional (2D) semiconductor platforms such as MoS₂. Here, we demonstrate a low-temperature (∼300 °C) plasma-induced crystallization strategy that stabilizes the orthorhombic phase in sputtered HZO films through plasma-induced modification of the oxygen-deficient defect configuration. This approach enables direct integration of ferroelectric HZO with bilayer MoS₂, integrating top-gate ferroelectric field-effect transistors (FeFETs) that exhibit robust polarization switching, a large memory window, on/off ratios exceeding 10⁶, reliable device-to-device uniformity, and long-term retention with projected stability beyond 10 years. The ability to induce ferroelectric phase formation at lower thermal budgets highlights the compatibility of plasma-processed HZO with 2D materials and back-end-of-line constraints. This work establishes a potential pathway toward monolithic 3D integration and advances the development of energy-efficient nonvolatile memory, neuromorphic hardware, and reconfigurable logic based on hybrid 2D ferroelectric device architectures.

Layered semiconductors offer a promising route beyond conventional silicon technology but face challenges in integrating high-k dielectrics due to their dangling-bond-free surfaces. Here, we report a direct atomic layer deposition approach, termed HALO (High-dose precursor immersion, Adsorption enhancement, and Low-temperature Oxide improvement) ALD, enabling uniform HfO₂ growth on two-dimensional (2D) materials without surface functionalization. The HALO process improves nucleation and interface quality, yielding smooth high-k films (∼0.1 nm roughness). MoS₂ dual-gate field-effect transistors (FETs) exhibit an equivalent oxide thickness of 0.83 nm, a subthreshold swing of 80 mV dec^–1, and breakdown fields up to 9 MV cm^–1. Reliability studies, including bias stress and thermal tests, confirm stable device operation. This approach further enables conformal high-k integration in gate-all-around structures, providing a scalable pathway for three-dimensional (3D) integration of 2D electronics.

Cr_1+δTe₂, a family among two-dimensional (2D) van der Waals (vdW) transition-metal dichalcogenides, has garnered significant interest owing to its tunable structural, electrical, and magnetic properties controlled by the concentration of self-intercalated Cr atoms. Among various external stimuli, pressure provides an additional route to tune the associated physical properties of these materials through modifications of interatomic distances, which can substantially alter the electrical and magnetic properties. In the present study, we report the theoretical and experimental investigation of the pressure-induced structural and electrical properties of Cr_1.28Te₂ with trigonal (P3̅m1) crystal structure. The pressure-dependent synchrotron X-ray powder diffraction (SXRPD) analysis revealed iso-structural transitions at ∼4.7, ∼9.9, and ∼19.7 GPa, evidenced by the deviation of lattice parameters from linear pressure dependence. The temperature-dependent resistance curves measured over a range of applied pressure show the presence of metal-semiconductor-metal transition near ∼7.8 and ∼16.8 GPa, close to the pressures of the iso-structural transitions. Additionally, a low-temperature resistance minimum observed at low pressures suggests the emergence of localization-related effects. The resistance minimum gradually shifts toward higher temperatures with increasing pressure, indicating the progressive enhancement of localization effect under compression. Further, theoretical calculations suggest that the metallic nature of Cr_1.28Te₂ below the metal-semiconductor transition (i.e., at low pressure) is dominated by Cr₂–3d states, whereas above the transition (at high pressure), the metallicity is governed by Te–3p states. A nonmonotonic evolution of the magnetic state is also observed under pressure, which is likely to originate from modified exchange interactions due to the change in bond lengths under applied pressure. Overall, the combined experimental and theoretical results provide a detailed insight into pressure-induced structural and electrical properties of Cr_1.28Te₂.

High-performance olfactory synapses are critical for efficient, wide-dynamic-range, and low-power neuromorphic sensing. Organic semiconductor devices, which offer advantages such as room-temperature operation, biocompatibility, and potential for large-scale manufacturing, represent a promising platform for olfactory synapse emulation. However, simultaneously enhancing both the synaptic weight and nonvolatility in organic semiconductor-based olfactory synapse devices remains a significant challenge. Here, we report a UV light activation strategy applied to a gas-sensing synaptic device based on the organic semiconductor dif-TES-ADT. Under UV illumination, the device exhibits a marked increase in response amplitude and a prolongation of recovery time. Exploiting this photoactivation effect, we successfully emulate both excitatory and inhibitory synaptic behaviors, achieving significantly enhanced synaptic weights and improved nonvolatility relative to those under dark conditions. Mechanistic studies suggest that this enhancement arises from the trapping of photogenerated charge carriers by gas molecules, which effectively increases the carrier density within the conduction channel. Furthermore, we demonstrate the device's capability to perform complex cognitive functions, including experience-dependent learning and Pavlovian conditioning. This work presents an effective strategy for synergistically regulating synaptic performance in organic neuromorphic devices, offering avenues for the development of multimodal perception and advanced neuromorphic computing systems.

Thermally evaporated CsPbBr₃ perovskite light-emitting diodes (PeLEDs) are fundamentally limited by high surface defect densities and severe carrier injection imbalance, which significantly constrain device efficiency and operational stability. Herein, we propose a dipole-modulated surface passivation strategy to address these critical challenges using three phenethylammonium bromide derivatives: phenethylammonium bromide (PEABr), 4-fluorophenethylammonium bromide (p-F-PEABr), and 4-trifluoromethylphenethylammonium bromide (p-CF₃-PEABr). The passivation mechanisms, together with the distinct effects of these derivatives on the perovskite films, are systematically investigated, clarifying the critical role of molecular dipole moments in determining passivation efficiency. Among these derivatives, p-CF₃-PEABr, which possesses the largest molecular dipole moment, exhibits the most effective defect passivation through strong coordination interactions with undercoordinated lead sites on the perovskite surface. Owing to effective surface defect passivation and the resultant suppression of nonradiative recombination, the optimized PeLED achieves a maximum external quantum efficiency (EQE) of 11.9% and a peak luminance of 40,341 cd m^–2, together with significantly enhanced operational stability. These findings demonstrate the promising potential of thermal evaporation for developing high-performance green-emitting CsPbBr₃ perovskite light-emitting devices.

Bismaleimide-Triazine (BT) resins are high-performance thermosetting polymers characterized by interpenetrating polymer networks (IPNs) or co-reacted network structures. As core dielectric materials, they combine low dielectric constant (D_k), low dissipation factor (D_f), and good thermal stability (T_g > 250 °C), supporting their use in advanced IC packaging and aerospace radomes. However, their intrinsic brittleness derived from high cross-link density necessitates toughening modifications. Furthermore, rapid growth in AI computing, high-speed communications, and satellite systems is increasing the demand for BT resins with lower dielectric loss and improved thermomechanical reliability. This review summarizes recent modification strategies, ranging from molecular structure design and reactive polymer blending to functional nanofiller and glass fabric reinforcement. Emphasis is placed on establishing fundamental structure-property relationships, clarifying how specific microstructural changes govern the dielectric response, thermal stability, and processability of BT resins. Ultimately, this review highlights the successful translation of these material innovations into cutting-edge functional applications, including memory chips, mmWave antenna substrates, high-speed data center interconnects, and satellite communications. This review may provide perspectives for the future development of advanced electronic packaging materials.

Thermoforming enables two-dimensional printed circuits to be converted into three-dimensional (3D) structures for in-mold electronics (IME), enabling electronic functionality to be integrated/embedded directly into molded plastic parts. However, during thermoforming, the substrate and printed conductors stretch and thin unevenly, creating resistance variations that lead to localized heating and reduced current-carrying capacity. This work demonstrates how conductive track geometry can be designed to compensate for these effects. Using screen-printed silver molecular inks on polycarbonate substrates, we compare the electrical performance of flat (two-dimensional, 2D) and thermoformed (3D) tracks and examine how localized widening of tracks in high-elongation regions influences performance. By selectively widening tracks in the elongated regions of thermoformed 3D conductors, resistance becomes more uniform and current-carrying capacity improves by at least ∼20%, approaching those of the analogous 2D tracks. Applying these design principles to compensate for thermoforming-induced changes in track resistance enabled the development of 3D serpentine heaters with a more uniform resistance distribution. The resulting temperature uniformity of the 3D serpentine heater improved from 50% to 74%. These results show that simple geometry modifications can minimize thermoforming-induced resistance variations and provide practical design guidelines for creating reliable 3D-printed electronic circuits for use in IME applications.

Cu₂Se is a well-known high zT thermoelectric (TE) material, but at room temperature it has poor TE properties due to its excessive carrier concentration resulting from spontaneously formed Cu vacancies. Attempts at carrier concentration optimization or band structure modification by doping have not been as successful because most dopants have low saturation limits in Cu₂Se and further lower the Cu vacancy formation energy, generating more vacancies that act as compensating dopants. We have found that by simultaneously adding excess Cu to suppress the formation of Cu vacancies and adding Yb dopants to modify the electronic band structure to enhance the Seebeck coefficient in Cu_2+xSe, a zT value of 0.57 at 300 K can be obtained for Cu_2.072Yb_0.003Se. The enhanced Seebeck coefficient, combined with the low thermal conductivity, yields high zT values at room temperature, making it a potential alternative for energy harvesting applications. Our results show that simultaneously suppressing Cu vacancies by adding excess Cu and band structure modification by adding an impurity dopant can be an effective strategy in enhancing the RT TE properties of Cu₂Se. This approach can also be effective in other Cu chalcogenide materials that are similarly plagued by excessive hole concentrations that result from Cu vacancies.