ACS Applied Electronic Materials最新文献

Gas and moisture sensing devices leveraging the resistive switching effect in transition metal oxide memristors promise to revolutionize next-generation, nanoscaled, cost-effective, and environmentally sustainable sensor solutions. These sensors encode readouts in resistance state changes based on gas concentration, yet their nonlinear current–voltage characteristics offer richer dynamics, capturing detailed information about REDOX reactions and surface kinetics. Traditional vertical devices fail to fully exploit this complexity. This study demonstrates planar resistive switching devices, moving beyond the Butler–Volmer model. A systematic investigation of the electrochemical processes in Na-doped ZnO with lateral planar contacts reveals intricate patterns resulting from REDOX reactions on the device surface. When combined with advanced algorithms for pattern recognition, these allow the analysis of complex switching patterns, including crossings, loop directions, and resistance values, providing unprecedented insights for next-generation complex sensors.

A transformation from conventional to enhanced inverse magnetocaloric effect is being investigated in ferrimagnetic Gd₃₅Fe₅Co₆₀ thin films at a lower temperature than the magnetic ordering temperature. RF magnetron sputtering is utilized to deposit 80 nm GdFeCo thin film sandwiched between Pt or Ta layers (Pt/GdFeCo/Pt and Ta/GdFeCo/Ta) on a Si (100) substrate to achieve optimal interfacial effects. A significant change in magnetic compensation temperatures (T_comp) and magnetic ordering is noticed. T_comp observed at 324.1 K for the Pt structure rises to 389.7 K for the Ta structure. The ferrimagnetic to paramagnetic phase transition, Curie temperature (T_c), is found at 586.8 and 664.3 K for Pt and Ta structures, respectively. The isothermal entropy change (ΔS_M) is estimated by applying 15 kOe in a wide temperature range (100 K < T < 750 K). The Pt structure shows maximum conventional and inverse magnetocaloric entropy changes (ΔS_M) of 1.09 and 0.78 J/kg K, respectively. The Ta structure transforms from conventional to inverse magnetocaloric entropy change with a maximum of 1.08 J/kg K at 15 kOe, which is higher than many thin films reported. These findings not only provide a deeper understanding of the interplay between interface interactions and magnetic dynamics but are also helpful in designing multilayered structures with enhanced magnetocaloric properties.

The peculiarities of radiative and nonradiative processes associated with self-trapped intrinsic eXcitons in the excited β-Ga₂O₃ crystals are studied via time-resolved techniques of induced absorption, transient grating, and photoluminescence (PL) at room temperature. The excitation above the bandgap is produced by laser pulses with linear light polarization parallel and orthogonal in the (-201) and (001) planes. We elucidate that the nonradiative recombination rate occurring in the eXciton prevails over its radiative emission rate in a wide range of free carrier concentration composed of excited and equilibrium electrons. Hence, the nonradiative recombination has no effect on the strong anisotropy and the shape of the eXciton emission band. However, we find out that the conventional ABC model of electron effective lifetime is insufficient for explanation of the excitation dependences. Inclusion of two nonradiative Auger mechanisms in a modified ABC formula provides excellent agreement of these dependences. We conclude that the trap-assisted Auger process is in proportion to the free electron density with coefficient B = 1.1 × 10^-11 cm³/s and appears at low/intermediate excitation, while the triple-particle Auger process is in proportion to Δn ² with coefficient C = 8 × 10^-30 cm⁶/s and appears at high excitation conditions. The transition between two Auger mechanisms is accompanied by a rise of the eXciton diffusivity in preferred crystallographic directions where the radiative PL intensity is maximal. The diffusion length L _D in these directions can reach values ∼300 nm, but, at high excitations, L _D becomes limited by Auger lifetimes. These findings pave the way for the implementation of self-trapped eXcitons into specific optoelectronic devices.

Developing high-performance electrocatalysts is crucial for electrochemical nonenzyme glucose sensing. In this work, irregular cuprous oxide nanospheres with remarkable electrocatalytic performance were synthesized by using a straightforward hydrothermal method. Notably, these irregular nanospheres were assembled from small nanocubes, and their formation was systematically studied with respect to both the time and temperature dependence. The resulting Cu₂O samples were evaluated for nonenzymatic glucose detection, demonstrating superior glucose oxidation performance. Among the samples, Cu₂O prepared at 170 °C for 2 h exhibited an outstanding sensitivity of 3056 μA·mM^–1·cm^–2, along with a broad and favorable linear range from 0.05 to 7.15 mM. Furthermore, the sensor showed excellent interference resistance and remarkable long-term stability. These findings underscore the significant potential of the synthesized Cu₂O nanospheres as a promising material for practical nonenzymatic glucose sensing.

Smart textiles play a vital role in physiological monitoring, mobile healthcare, and human–machine interface. Multifunctionality remarkably benefits the miniaturization and integration of wearable electronics. Here, we developed a PANI@PDA/PVDF composite textile (PCT)-based multifunctional sensor by combining electrospinning with in situ polymerization. This prepared multifunctional sensor features a wide pressure detection range (0–70 kPa), high sensitivity (10.1 [kPa]⁻¹), fast response rate, and excellent stability, which is capable of discerning subtle pulse, respiratory patterns, and limb movement. Furthermore, the PDA anchoring-enabled π–π conjugation effect promises good ammonia sensing performance with a sensitivity of 1.76% ppm^–1 and a response of 320.5% at 200 ppm of NH₃, demonstrating great potential in distinguishing the biomarker for kidney disease prognosis. This work unravels the possibility for constructing multifunctional biomonitoring devices for multimodal physiological diagnosis.

Polyaramid fibers (AFs), known for their exceptional tensile strength and modulus, gain their robust mechanical properties from extensive hydrogen bonding, which enhances interface bonding and stress transmission. When combined with conductive fillers, these fibers can form composite sheets with both strong mechanical and electrical performance. This study presents a lightweight, flexible, and conductive polyaramid paper (Cu-Kevlar) that integrates a hierarchical polyaramid fiber microstructure with copper nanoplate fillers. The composite achieved high electrical conductivity (1.14 MS/m) and tensile strength (7.51 MPa). A stretchable paper heater, fabricated using a kirigami design, demonstrated rapid heating to 80 °C within 60 s at an operating voltage of 1.5 V, showing its potential for low-power thermal applications. Additionally, the material provides effective electromagnetic interference (EMI) shielding with a shielding effectiveness of 70.59 dB at 8 GHz. This work offers a versatile approach to creating lightweight, flexible, and conductive paper with efficient joule heating and EMI shielding capabilities, enabling applications in flexible electronics, thermal management, and protective shielding.

III–VI compounds, such as In_xSe_y materials, offer an unprecedented potential for electronic devices at the atomic level. Despite their superior electronic properties, most research focused on measuring transport locally within mechanically exfoliated flakes at microscale and sometimes transferred on atomically flat surfaces. However, from a technological perspective, the integration of these materials in electronic devices requires wafer-scale, uniformly grown films, preferably integrated with the dominant semiconductor, silicon. Indium selenide films have recently shown promising electronic performance. Unfortunately, the epitaxial growth of single-phase indium selenide poses challenges due to its polymorphic nature and different stoichiometries, such as α-In₂Se₃, ε-for InSe, and β, γ for both InSe and In₂Se₃. Here, we report the growth of single phase γ-In₂Se₃ on Si (100), with a Hall mobility exceeding 2000 cm²/(V s) at room temperature. Our study explores the growth parameter space in the Molecular Beam Epitaxy (MBE), specifically the Se/In flux ratio and the growth temperature. It correlates them with the structural, morphological, and electrical characteristics of In_xSe_y films. A phase map was constructed within the specified growth temperature and Se/In flux ranges. γ-In₂Se₃ single phase formation occurs only in a small temperature and Se/In Flux ratio window. In contrast, the formation of a mixture of γ-InSe and γ-In₂Se₃ phases is obtained in a large growth condition window. The sensitivity of indium selenide’s electrical and morphological properties to growth conditions implies the necessity for precise adjustments of the Se/In flux ratio alongside the growth temperature to selectively grow large-area single-phase γ-In₂Se₃ suitable for advanced electronic devices such as field effect transistors and photodetectors.

Self-powered polarization-sensitive photodetectors play an important role in considerable fields such as navigation, military reconnaissance, and medical imaging. In this paper, a Sb₂Se₃/PEDOT heterojunction was developed by spraying a PEDOT film to a single Sb₂Se₃ microbelt (MB) with high crystallinity, synthesized using the CVD process. The self-powered Sb₂Se₃/PEDOT photodetector (PD) exhibits high polarization-sensitive and broadband detection in the visible–near-infrared range (368–1300 nm). The device achieves a high on/off ratio of 1804, maximum responsivity and specific detectivity of 2.33 A W^–1 and 3.84 × 10¹² Jones, and fast response time (23 ms/60 ms) at 724 nm under zero bias. The Sb₂Se₃/PEDOT PD exhibits excellent polarization sensitivity characteristics with the highest anisotropy ratio of 1.7 under 724 nm at zero bias, which is 1.13 times higher compared to the Sb₂Se₃ PD (1.32) at 0.2 V. The enhanced ability to detect polarized light of the Sb₂Se₃/PEDOT PD can be attributed to inherent anisotropy of the Sb₂Se₃ MB and good polarization-sensitivity of PEDOT to form a type II heterojunction, which is suitable for fast separation of photogenerated carriers. Excellent imaging capabilities of the letters “JN” and sensitivity to polarized light at 724 nm have been established for the high-resolution single-pixel image sensor at 0 V bias. This work demonstrates an effective strategy for high-optical response, self-powered, polarization-sensitive photodetection, and imaging using Sb₂Se₃/PEDOT heterojunctions.

Tin (Sn)-based perovskite light-emitting diodes (PeLEDs) have garnered significant attention owing to their superior optoelectronic properties, affordable solution processing, and environmental friendliness. However, the properties of Sn-PeLEDs trail those of their lead (Pb) counterparts. The main obstacle is the easy oxidation of Sn²⁺ to Sn⁴⁺ as well as fast crystallization, leading to poor film quality with many defects. Herein, a convenient and effective interface engineering strategy is reported to fabricate (2-thiopheneethylamine)₂SnI₄ (TEA₂SnI₄) PeLEDs by introducing different peptides into the PEDOT:PSS hole-transport layer (HTL). Benefiting from the interaction between the peptide molecules and the Sn-perovskite nuclei, the crystallization dynamics are effectively adjusted, leading to an improved film morphology. At the same time, the multiple functional groups of peptides can suppress Sn²⁺ oxidation and passivate interface defects. Therefore, perovskite films with improved luminescence efficiency are obtained. The perovskite films are further used for the fabrication of pure red PeLEDs with enhanced performance. In particular, the optimized devices based on Leu-Gly-Gly (LGG) achieve a peak external quantum efficiency of 0.5% and a brightness of 136 cd m^–2, which are about 2 and 3 times larger, respectively, than those of the reference device. This research offers a general strategy to improve the performance of Sn-PeLEDs via peptide interface engineering.

Carbon fiber papers (CFPs) with high electrical conductivity have recently received considerable attention in related apparatus; however, there is still limited research on their poor mechanical strength under the multifield coupling case. In this work, we reported a hard crystal network-assisted interfacial engineering strategy to partially reinforce the conductive carbon fiber skeleton with polyethylene glycol terephthalate (PET) fibers. The rigid connections, introduced by the cold crystallization of melting PET fibers, can physically lock up the carbon fibers while effectively maintaining an in situ carbon fiber lap point, avoiding electric transmission obstacles. The optimized CFPs exhibit comprehensive performance advantages, with a fracture strength of 33.7 MPa and an electrical conductivity of 64.1 S m^–1. The CF/PET composite paper also demonstrates satisfactory electrical heating performance and excellent electromagnetic shielding capabilities, underscoring the considerable potential of CFPs for a wide range of applications.