Science China Materials最新文献

Amorphous gallium oxide (a-Ga₂O₃) has a low carrier concentration and limited mobility, which constrains its application in neuromorphic computing. In this study, Zn-doped Ga₂O₃ (ZGO) artificial synaptic devices were fabricated under oxygen-free conditions using radio-frequency magnetron sputtering (RFMS). Compared to undoped Ga₂O₃, the ZGO device exhibited a 106-fold increase in excitatory postsynaptic current under 254 nm illumination, with the response intensity positively correlated with the optical pulse parameters. Under light pulse modulation, the devices demonstrated dynamic behavior transitioning from short-term plasticity to long-term plasticity, including paired-pulse facilitation and the learning-forgetting-relearning process. Furthermore, the electrical and optical energy consumption of synaptic events are as low as 28 fJ and 2 nJ, respectively. The mechanism analysis indicates that the persistent photoconductivity effect in the ZGO thin film is attributed to the abundant oxygen vacancies. A multi-layer perceptron simulation based on ZGO devices achieved a 90.74% accuracy in handwritten digit recognition, and maintained 76.18% accuracy even with 50% noise. Zn doping provides a new material design approach for Ga₂O₃-based neuromorphic devices, demonstrating potential for future applications in neuromorphic computing.

In this work, cation vacancies induced the tetrahedral distortion, enhancing the second harmonic generation (SHG) response in the diamond-like (DL) structure compounds. Concretely, the high valence and electronegativity of P⁵⁺ were introduced to substitute the Ge⁴⁺ in Cd₄GeS₆, which shows a general SHG response of 1.1 × AgGaS₂ (AGS) at 2050 nm. Thus, the isomorphic defective DL Cd_3.5PS₆ was obtained with inherent Cd²⁺ vacancies, leading to an 8.5-fold increase in [CdS₄] tetrahedral distortion degree than Cd₄GeS₆. As a result, Cd_3.5PS₆ has a high SHG response of 2 × AGS at 2050 nm and a laser-induced damage threshold (LIDT) of 9.4 × AGS. Furthermore, equivalent Hg²⁺ substitution concentrates Cd²⁺ vacancies at the Cd(2) site, leading to a 2.66-fold [CdS₄] tetrahedral distortion degree than Cd_3.5PS₆. Consequently, Hg_0.5Cd₃PS₆ possesses a high SHG response of 2.73 × AGS at 2050 nm and LIDT of 5 × AGS with a birefringence of 0.076@2050 nm. The results indicate that the cation vacancies and radius scale of mixed atoms provide effective ways to design high-performance nonlinear optical crystals.

Rechargeable lithium batteries (LBs) that can withstand extreme temperatures (high and low, HT/LT) are essential for achieving carbon neutrality. However, the operational reliability of current LBs deteriorates significantly when exposed to these conditions. Electrolyte additives characterized by a small dosage, low cost, and minimal reduction in energy density have been shown to mitigate thermal challenges effectively by regulating interfaces and enhancing ion transport. This review systematically examines the failure mechanisms of electrolytes under HT/LT conditions, including thermally driven side reactions, sluggish ion migration and the formation of an unstable solid electrolyte interphase (SEI). State-of-the-art additives are classified and their working mechanisms, functions, advantages and disadvantages are analyzed. Design principles for advanced additives are proposed, emphasizing the synergistic optimization of oxidative stability at HT and ion mobility at LT. Although these strategies are tailored to lithium-based systems, they offer transferable insights for other metal-based batteries (e.g., sodium/potassium) that struggle with temperature-dependent performance degradation.

AgInS₂, a representative I–III–VI₂ chalcogenide, has garnered significant attention due to its tunable electronic structure, nontoxic nature, and air stability. However, its practical application is hindered by severe nonradiative recombination losses induced by deep-level In_Ag antisite defects, which act as carrier trapping centers. While Sb and Bi doping have been shown to suppress defect states in CuInS₂, their impact on AgInS₂ remains unexplored. This study systematically investigates Sb and Bi doping in AgInS₂ from the perspectives of electronic orbitals interactions and defect regulation. Under S-rich, In-poor, and Ag-moderate conditions, the formation energy of In_Ag defects increases, thereby reducing their concentration. Sb_In and Bi_In emerge as dominant dopant-induced defects, yet they exhibit distinct effects on carrier recombination. Sb doping introduces deep-level states at 1.08 eV below the conduction band minimum through strong Sb–S antibonding interactions, exacerbating nonradiative recombination losses while reducing the radiative recombination coefficient by three orders of magnitude to 1.36×10⁻¹⁶ cm³/s versus intrinsic AgInS₂’s 9.63×10⁻¹³ cm³/s. In contrast, Bi_In defects remain neutral across the Fermi level range, with Bi doping demonstrating superior defect tolerance that effectively suppresses deep-level states and promotes radiative recombination. This enhances the radiative recombination coefficient by one order of magnitude to 1.27×10⁻¹² cm³/s. This study offers critical insights into lone-pair electron effects in Ag-based chalcogenides, contributing to the advancement of sustainable and high-efficiency optoelectronic materials.

The rapid development of artificial intelligence and the Internet of Things has generated an urgent demand for brain-inspired computing systems characterized by high parallel processing capabilities. However, the power consumption of most reported artificial synaptic devices remains substantially higher than that of their biological counterparts, which operate at the femtojoule (fJ) level per synaptic event. To this end, this research aims to develop ultralow-power silicon carbide (SiC) plasmonic nanowire network (NWN)-based artificial synaptic devices for using in musical classification neural network system. By leveraging the neural network-like physical architecture of the NWN and the alteration of conductance states at NW-NW junctions, the SiC/SiO₂@Ag NWN devices successfully emulate both ultraviolet (UV) visual and electrical synaptic functions under both externally biased electric field modulation mode and zero-bias photoexcitation mode conditions. Furthermore, due to the confinement effects of one-dimensional nanomaterials and the localized surface plasmon resonance (LSPR) induced by Ag nanoparticles, these devices exhibit substantial synaptic responses at ultra-low currents with minimal power consumption. With its low power consumption, the SiC/SiO₂@Ag NWN synapses exhibit superior performance in simulating music classification recognition, achieving an accuracy exceeding 95% within 20 epochs. Notably, the innovative SiC NWN structure ensures robust synaptic performance and high precision in neural network computations. This advancement has the potential to drive the development of novel computing architectures, such as spiking neural networks (SNNs), which more closely mimic the operational principles of biological neural networks, thereby facilitating enhanced music information processing.

Terpyridine-lanthanide (tpy-Ln) metallo-supramolecular polymers have garnered significant attention in supramolecular chemistry, coordination chemistry and materials science on account of the rigid structure, tunable electronic properties and strong coordination ability of tpy, as well as the unique electronic configuration and remarkable optical, magnetic properties of lanthanides. Over the past decade, the development of tpy-Ln metallo-supramolecular polymers has experienced rapid growth. This review provides an overview of recent progress in tpy-Ln metallo-polymers, covering both crystalline structures and amorphous forms. We focus on the synthesis of these metallo-polymers, with particular emphasis on their structural diversity and self-assembly strategies. Notably, we highlight their promising applications as luminescent materials, chemical sensors, and magnetic materials. Ultimately, this review aims to inspire further exploration into the rational design and synthesis of functional tpy-Ln metallopolymers with enhanced structural precision and enriched functionality, paving the way for their integration into emerging technological applications.

The development of brain-inspired neural network computing synaptic devices based on organic field-effect transistors (OFETs) represents a pivotal research frontier in neuromorphic computing and flexible electronics. These devices elucidate fundamental mechanistic parallels between biological neural networks and artificial systems, facilitating the paradigm shift in organic electronics from passive “sensing” to active “cognition”. This technological evolution enables loop perception-computation-decision architectures while unlocking transformative opportunities in intelligent hardware and medical technologies. Such pioneering advancements are poised to redefine the global semiconductor industry landscape by bridging neuromorphic engineering with next-generation bioelectronic applications, ultimately driving the convergence of adaptive learning systems and human-machine symbiotic interfaces. A low-voltage (1 V) C₈-BTBT optoelectronic synaptic array (coefficient of variation in synaptic weight modulation: 8%) emulated human visual information processing under distinct cognitive states: dispersed-attention mode achieved rapid response and short-term plasticity, while focused-attention mode enabled noise suppression and long-term potentiation via carrier trapping modulation. This platform advances hardware-level perception-computation integration for biomimetic vision chips.

The brain’s selective visual attention mechanism (SVAM) enables robust visual recognition in noisy environment through diverse neural action potential peaks acting as filters. Spiking neural networks (SNNs) mimic this paradigm but limited noise immunity and high write current density hinder brain-like efficiency. Hardware implementing SVAM necessitates spiking spintronic devices with noise-resistant and low operation current densities; such devices remain unreported. Here, we report an orbit-torque (OT) actuated ferromagnetic spiking synapse and neuron featuring a tunable peak action potential. These are more akin to the biological neurons with varying sensitivities to external sensory stimuli, thereby augmenting the perception aptitude of the system in complex surroundings. Capitalizing on the high-efficient OT, the ferromagnetic device demands a write current density of 5 × 10⁶ A/cm², which is an order of magnitude lower than other spiking devices actuated by spin-orbit torque. Leveraging these neuromorphic devices, an all-spin SNN with low current density and tunable action potential peak has been fabricated, successfully mimicking the SVAM. In complex noise environment, the SNN achieves 92% on Cifar-10 and 95% on MNIST dataset, surpassing state-of-the-art spin-based SNNs by 5%. Our work provides a promising avenue for exploring the SVAM-inspired spiking neuromorphic devices, enhancing the bionic performance of the SNNs.

Flexible photonic crystal (PC) materials possess exceptional optical properties. However, their structures often deteriorate under repeated mechanical responses, which may lead to structural impairments within the photonic band gap. This poses a challenge to their sustainability. Herein, by introducing a self-healing thermoplastic polyurethane (STPU) material with inverse-opal PC structure, a self-healing discoloration skin with stress response is prepared, inspired by the structural coloration and self-healing mechanisms of natural organisms. Given the synergistic effects of dynamic covalent bonds (S-S bonds) and hydrogen bonds (H-bonds), STPU can be reversibly adjusted upon mechanical deformation, enabling it to coordinate with environmental changes and showing excellent mechanical strength (26.76 MPa) and elongation at break (2000%). At the same time, the inverse opal structure inside STPU gives composite reversible color transitions with sensitive optical responses to solvents (e.g., water and ethanol) and mechanical stress (0%–70% strain) through the regulation of lattice spacing. Furthermore, the incorporation of an interpenetrating network composed of polyacrylamide hydrogel and carbon nanotubes enhances its strain sensitivity and structural color stability. More importantly, given its excellent self-healing properties, it exhibits broad application potential in flexible sensors, adaptive optical devices, bioinspired robotic skins, and dynamic anticounterfeiting encryption, overcoming the limitations of traditional PCs (e.g., high fragility and single functionality). The proposed strategy paves the way for the development of durable intelligent sensing materials with enhanced environmental adaptability and multifunctional integration.