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Interface engineering is pivotal for enhancing the performance and stability of devices with layered structures, including solar cells, electronic devices, and electrochemical systems. Incorporating the interfacial dipole between the bulk layers effectively modulates the energy level difference at the interface and does not significantly influence adjacent layers overall. However, interfaces can drastically affect adjoining layers in ultrathin devices, which are essential for next‐generation electronics with high integrity, excellent performance, and low power consumption. In particular, the interfacial effect is pronounced in ultrathin semiconductors, which have a weak electric field screening effect. Herein, the substantial interfacial impact on the ultrathin silicon is shown, the p‐ to n‐type inversion of the semiconductor solely through the deposition of a self‐assembled monolayer (SAM) without external bias. The effects of SAMs with different interfacial dipoles are investigated by using Hall measurement and surface analytic techniques, such as UPS, XPS, and KPFM. Furthermore, the lateral electronic junction of the ultrathin silicon is engineered by the regioselective deposition of SAMs with opposite dipoles, and the device exhibits rectification behavior. When the interfacial dipole of SAM is manipulated, the rectification ratio changes sensitively, and thus the fabricated diode shows potential to be developed as a sensing platform. [ABSTRACT FROM AUTHOR]

Water motion‐induced energy harvesting has emerged as a prominent means of facilitating renewable electricity from the interaction between nanostructured materials and water over the past decade. Despite the growing interest, comprehension of the intricate solid–liquid interfacial phenomena related to solid state physics remains elusive and serves as a hindrance to enhancing energy harvesting efficiency up to the practical level. Herein, the study introduces the energy harvester by utilizing inversion on the majority charge carrier in graphene materials upon interaction with water molecules. Specifically, various metal electrode configurations are employed on reduced graphene oxide (rGO) to unravel its distinctive charge carriers that experience the inversion in semiconductor type upon water contact, and exploit this characteristic to leverage the efficacy of generated electricity. Through the strategic arrangement of the metal electrodes on rGO membrane, the open‐circuit voltage (Voc) and short‐circuit current (Isc) have exhibited a remarkable augmentation, reaching 1.05 V and 31.6 µA, respectively. The demonstration of effectively tailoring carrier dynamics via electrode configuration expands the practicality by achieving high power density and elucidating how the water‐induced carrier density modulation occurs in 2D nanomaterials. [ABSTRACT FROM AUTHOR]

All‐solid‐state Li‐metal battery (ASSLB) represents advantageous energy storage system for automotive applications. For ASSLB, inorganic solid electrolyte is essential in determining safety and cycling performance. However, significant challenges persist in practical construction of ASSLB with optimized electrolyte. Specifically, electrolyte's structural instability influencing its electrochemical performance remains critical issue within typical operating temperatures for ASSLB in electric vehicles. Herein, this challenge is fundamentally addressed by substituting trace amount of lithium with cadmium, which lacks crystal field stabilization energy. This strategy of atomic interaction modification has induced electrolyte's structural distortion and electronic alteration by deliberately introducing disorder at local lithium sites. Li symmetric cell with cadmium‐substituted antiperovskite solid electrolyte exhibits outstanding critical current density of 11.5 mA cm−2 (5.75 mAh cm−2) and excellent stability for 3000 h at 10.0 mA cm−2 (5.0 mAh cm−2). This study highlights explicit research direction for breakthrough of ASSLB, focusing on understanding how local distortion affects complex inorganic materials. [ABSTRACT FROM AUTHOR]

Interest has grown in services that consume a significant amount of energy, such as large language models (LLMs), and research is being conducted worldwide on synaptic devices for neuromorphic hardware. However, various complex processes are problematic for the implementation of synaptic properties. Here, synaptic characteristics are implemented through a novel method, namely side chain control of conjugated polymers. The developed devices exhibit the characteristics of the biological brain, especially spike‐timing‐dependent plasticity (STDP), high‐pass filtering, and long‐term potentiation/depression (LTP/D). Moreover, the fabricated synaptic devices show enhanced nonvolatile characteristics, such as long retention time (≈102 s), high ratio of Gmax/Gmin, high linearity, and reliable cyclic endurance (≈103 pulses). This study presents a new pathway for next‐generation neuromorphic computing by modulating conjugated polymers with side chain control, thereby achieving high‐performance synaptic properties. [ABSTRACT FROM AUTHOR]

Synaptic devices that mimic biological neurons have attracted much attention for brain-inspired neuromorphic computing. Especially, synaptic thin-film transistors (TFTs) have emerged with simultaneous signal processing and information storage advantages. However, the analysis of excitatory postsynaptic current (EPSC) relies on an empirical model such as a serial RC circuit, which limits a systematic and in-depth study of synaptic devices in terms of material and electrical properties. Herein, the single-pulse-driven synaptic EPSC (SPSE) model, including capacitive effect and information of the synaptic window, is analytically proposed. The SPSE model can simulate EPSC of synaptic devices at given TFT-operating conditions. EPSC with the SPSE model can be characterized with quantified parameters for the capacitive effects and the synaptic windows, which also depend on the electrical condition applied to TFTs. Various kinds of synaptic-TFTs with different gate insulators (e.g., SiO2 and ion-gel) are used to confirm the performance of the SPSE model. For example, the SPSE model can capture the long-term robustness of ion-gel-based TFTs with specific quantified parameters. In addition, the SPSE model enables the estimation of energy consumption, which can potentially be leveraged to compare the energy cost of EPSC fairly. The SPSE model can provide a guideline to understand the physical properties of synaptic TFTs. [ABSTRACT FROM AUTHOR]

Machine learning (ML) provides temporal advantage and performance improvement in practical electronic device design by adaptive learning. Herein, Bayesian optimization (BO) is successfully applied to the design of optimal dual‐layer oxide semiconductor thin film transistors (OS TFTs). This approach effectively manages the complex correlation and interdependency between two oxide semiconductor layers, resulting in the efficient design of experiment (DoE) and reducing the trial‐and‐error. Considering field effect mobility (휇) and threshold voltage (Vth) simultaneously, the dual‐layer structure designed by the BO model allows to produce OS TFTs with remarkable electrical performance while significantly saving an amount of experimental trial (only 15 data sets are required). The optimized dual‐layer OS TFTs achieve the enhanced field effect mobility of 36.1 cm2 V−1 s−1 and show good stability under bias stress with negligible difference in its threshold voltage compared to conventional IGZO TFTs. Moreover, the BO algorithm is successfully customized to the individual preferences by applying the weight factors assigned to both field effect mobility (휇) and threshold voltage (Vth). [ABSTRACT FROM AUTHOR]

Li+ electrolyte-gated transistors (EGTs) have attracted significant attention as artificial synapses because of the fast response of Li+ ion, low operating voltage, and applicability to flexible electronics. Due to the inherent nature of Li+ ion, Li+ EGTs show, however, limitations, such as poor long-term synaptic plasticity and nonlinear/nonsymmetric conductance update, which hinder the practical applications of artificial synapses. Herein, Li+ EGTs integrated with poly(vinylidene fluoride-co-trifluoroethylene) (PVDF-TrFE) ferroelectric polymer as a channel–electrolyte interlayer are presented. Owing to the polarized domains of PVDF-TrFE, the transport of Li+ ions at the channel–electrolyte interface is accelerated, and Li+ ions effectively penetrate the channel. Moreover, the self-diffusion of Li+ ions from the channel to the electrolyte is suppressed by the downward polarized domains. Li+ EGTs, therefore, successfully demonstrate synaptic characteristics, including excitatory postsynaptic current, short-/long-term synaptic plasticity, and paired-pulse facilitation. Also, conductance update in Li+ EGTs shows a dynamic range (Gmax/Gmin) of 92.42, high linearity, and distinct stability over 100 cycles. Based on their synaptic characteristics, inference simulations using a convolution neural network for the CIFAR-10 dataset imply that Li+ EGTs are suitable as artificial synapses with an inference accuracy of 89.13%. The new methodological approach addressing modulation of ion dynamics at the interface is introduced for developing practical synaptic devices. [ABSTRACT FROM AUTHOR]

Anode‐free Li metal batteries (AFLMBs) are highly advantageous due to their high energy density, low cost, and simple fabrication. However, severe challenges, such as uncontrolled dendrite formation and low coulombic efficiency, restrict their practical application. Herein, this work introduces a silver nanoparticles incorporated p‐doped conjugated polymer (Ag‐PCP) wetting agent on the copper current collector, which promotes both uniform Li nucleation and rapid formation of a LiF‐rich solid electrolyte interphase (SEI) at the early stage, resulting in interfacial stabilization and high Li utilization efficiency. Moreover, this work verifies the interfacial fluorinated mechanism of the Ag‐PCP to efficiently achieve a favorable SEI chemistry, which serves as an intermediate process for promoting LiF formation. Benefiting from the synergistic effect of Ag–Li alloying and F‐doping chemistry of the Ag‐PCP chains, the deposited Li exhibits a compact column‐like structure with dendrite‐free morphology, and the anode‐free cells display superior cycling stability with long lifespan even under harsh conditions, with the LFP//Ag‐PCP│Cu full cell having a high capacity retention of 72% (Li inventory retention rate, 99.8%) at 1 C‐rate after 200 cycles. [ABSTRACT FROM AUTHOR]

Thin‐film transistors (TFTs) based on ternary or quaternary metal oxides possess features that are advantageous for the commercialization of large‐area and flexible displays. These features include high mobility, high current on–off ratio, and uniformity over large areas. However, the manufacture of TFTs mainly uses costly sputtering equipment with low throughput. Here, it is demonstrated that cation exchange is a novel, solution‐based route for obtaining high‐quality ternary metal oxide films from binary metal oxide films. Specifically, some Zn ions in the parent ZnO film are replaced with In or Sn ions in a solution at room temperature, while preserving the ionic framework of the parent ZnO lattice to some degree. Consequently, annealing the resulting cation‐exchanged film at 250 °C yields an In‐ or a Sn‐doped ZnO film, in which In or Sn acts as a substitutional donor, with its electrical properties superior to those of the parent ZnO film. With the use of these In‐ and Sn‐doped ZnO films as channel layers, TFTs exhibit field‐effect mobilities of 10.3 and 7.1 cm2 V−1 s−1 and turn‐on voltages of −3.9 and −1.2 V, respectively, with current on–off ratios exceeding 108. [ABSTRACT FROM AUTHOR]

Li+ electrolyte‐gated transistors (EGTs) have received much attention as artificial synapses for neuromorphic computing. EGTs, however, have been still challenging to achieve long‐term synaptic plasticity, which should be linearly and symmetrically controlled with the magnitude of electrical potential at the gate electrode. Herein, a fluoroalkylsilane (FAS) self‐assembled monolayer (SAM) is introduced as a channel‐electrolyte interlayer with the function of sequential ion‐trapping in Li+ EGTs. It is demonstrated that the retention of Li+ ions can be enhanced, resulting in stable non‐volatile channel conductance update with high fidelity, linearity, and symmetry in EGTs treated with FAS with 5 fluoroalkyl chains. Through investigating electrical analysis and chemical analysis, it is verified that fluoroalkyl chains enable the sequential ion‐trapping at the channel‐electrolyte interface by coulombic attraction between Li+ ions and fluorocarbons. Simulations of artificial neural networks using 20 × 20 digits show FAS‐treated EGTs are suitable as artificial synapses with an accuracy of 89.71% by identical gate pulses and 91.97% by non‐identical gate pulses. A methodological approach is newly introduced for developing synaptic devices based on EGTs for neuromorphic computing with high fidelity. [ABSTRACT FROM AUTHOR]

Electrolyte‐gated transistors (EGTs) have been extensively studied as a next‐generation neuromorphic device mimicking the biological ionic flux in synapses. However, its long‐term plasticity characteristic lasts only for few seconds because of the rapid self‐discharge of electrical double layer. Here, ultraviolet ozone (UVO) treated water‐in‐bisalt (WiBS)/polymer electrolyte‐gated synaptic transistor (WEST) which excellently implements multiple synaptic functions is proposed. Ultraviolet (UV) light and reactive oxygen radicals generated during UVO treatment form trap sites on the surface of active layer, causing lithium cations in the WiBS/polymer electrolyte to be captured at the electrolyte/active layer interface. The UVO treated WEST shows enhanced nonvolatile memory performance for 10 000 s, up to 1186 times longer than that of the untreated WEST. Also, near‐ideal weight update over 10 000 cycle tests with 0.32 and −0.55 nonlinearities of long‐term potentiation and depression is acquired with a ten times improved symmetricity. These results confirm that the surface engineering is a key technique for sophisticated ion transport, and demonstrate various applicability of EGTs as a neuromorphic device. [ABSTRACT FROM AUTHOR]

Interfacial instability between Li‐metal anode (LMA) and inorganic solid‐state electrolyte (SSE) is a critical issue in all‐solid‐state Li‐metal batteries (ASSLBs). Previous studies have focused on interface modification methodology to achieve long‐term cycling stability in ASSLBs. However, strategy establishment without an in‐depth understanding of the LMA–SSE interface is limited to a phenomenological solution. Also, the fact that rechargeable batteries are operated by behavior of charges inside electric field is frequently overlooked. Here, it is demonstrated for the first time that interface modeling based on energy band theory does effectively overcome the intrinsic vulnerability of SSE to LMA. The interfacial deterioration, due to undesirable electron transport from LMA to the SSE surface, is precluded by a titanium compound self‐induced interlayer (TSI), which forms an interfacial energy barrier. The Li symmetric cell with a TSI successfully maintains its constant overpotential over 1000 cycles and the significantly reduced impedance, whereas the cell having no interface modification exhibits erratic voltage profiles and is easily failed by repetitive charge–discharge process. This newly introduced approach is an informative tool to substantially reinforce the fundamental understanding of interfacial phenomena in all‐solid‐state batteries. Furthermore, rigorous stability requirements of automotive applications are expected to be fulfilled by the innovative interface modification. [ABSTRACT FROM AUTHOR]