Liquid-like pseudoelasticity of sub-10-nm crystalline silver particles

Sun, Jun; He, Longbing; Lo, Yu‐Chieh; Xu, Tao; Bi, Hengchang; Sun, Litao; Zhang, Ze; Mao, Scott X.; Li, Ju

doi:10.1038/nmat4105

Cited by 268 publications

(277 citation statements)

References 38 publications

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“…The material systems exhibiting a substantial relaxation were those with large wetting contact angles 32 , such as MgO x :Ag, SiO x N y :Ag, and HfO x :Ag in Fig. 1b, consistent with the reported psudoelasticity of silver nanoparticles 33 and the hypothesis that interfacial energy facilitates filament rupture in volatile switching [34][35][36] .…”

supporting

confidence: 82%

Memristors with diffusive dynamics as synaptic emulators for neuromorphic computing

et al. 2016

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The accumulation and extrusion of Ca 2+ in the pre-and postsynaptic compartments play a critical role in initiating plastic changes in biological synapses. To emulate this fundamental process in electronic devices, we developed diffusive Ag-in-oxide memristors with a temporal response during and after stimulation similar to that of the synaptic Ca 2+ dynamics. In situ high-resolution transmission electron microscopy and nanoparticle dynamics simulations both demonstrate that Ag atoms disperse under electrical bias and regroup spontaneously under zero bias because of interfacial energy 2 minimization, closely resembling synaptic influx and extrusion of Ca 2+ , respectively.The diffusive memristor and its dynamics enable a direct emulation of both short-and long-term plasticity of biological synapses and represent a major advancement in hardware implementation of neuromorphic functionalities.CMOS circuits have been employed to mimic synaptic Ca 2+ dynamics, but three-terminal devices bear limited resemblance to bio-counterparts at the mechanism level and require significant numbers and complex circuits to simulate synaptic behavior [1][2][3] . A substantial reduction in footprint, complexity and energy consumption can be achieved by building a two-terminal circuit element, such as a memristor directly incorporating Ca 2+ -like dynamics.Various types of memristors based on ionic drift (drift-type memristor) 4-8 have recently been utilized for this purpose in neuromorphic architectures [9][10][11][12][13][14][15] . Although qualitative synaptic functionality has been demonstrated, the fast switching and non-volatility of drift memristors optimized for memory applications do not faithfully replicate the nature of plasticity. Similar issues also exist in MOS-based memristor emulators [16][17][18] , although they are capable of simulating a variety of synaptic functions including spike-timing-dependent plasticity (STDP). Recently, Lu's group adopted second-order drift memristors to approximate the Ca 2+ dynamics of chemical synapses by utilizing thermal dissipation 19 or mobility decay 20 , which successfully demonstrated STDP with non-overlapping spikes and other synaptic functions, representing a significant step towards bio-realistic synaptic devices. This approach features repeatability and simplicity, but the significant differences of the dynamical response from actual synapses limit the fidelity and variety of desired synaptic functions. A device with similar physical behavior as the biological Ca 2+ dynamics would enable improved emulation of synaptic function and broad applications to neuromorphic computing. Here we report such an emulator, which is a memristor based on metal atom 3 diffusion and spontaneous nanoparticle formation, as determined by in situ high-resolution transmission electron microscopy (HRTEM) and nanoparticle dynamics simulations. The dynamical properties of the diffusive memristors were confirmed to be functionally equivalent to Ca 2+ in bio-synapses, and their operating characteri...

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confidence: 82%

Memristors with diffusive dynamics as synaptic emulators for neuromorphic computing

et al. 2016

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“…Such a discrepancy can be attributed to the strong coalescence of high-purity singlets on fibers during deposition. 38 Coalescence ceases when the NPs reach a critical size beyond which agglomerates becomes dominant. 27 Comparing the peaks of the WAXS curves corresponding to the raw fabric with those of the nanofinished fabric, an additional peak at 2θ = 38.1º is related to crystalline phase Ag (111).…”

Section: Resultsmentioning

confidence: 99%

Scalable and Environmentally Benign Process for Smart Textile Nanofinishing

Feng

Hontañón

Blanes

et al. 2016

ACS Appl. Mater. Interfaces

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A major challenge in nanotechnology is that of determining how to introduce green and sustainable principles when assembling individual nanoscale elements to create working devices.For instance, textile nanofinishing is restricted by the many constraints of traditional pad-drycure processes, such as the use of costly chemical procedures to produce nanoparticles (NPs), the high liquid and energy consumption, the production of harmful liquid waste, and multi-step batch operations. By integrating low-cost, scalable, and environmentally benign aerosol processes of the type proposed here into textile nanofinishing, these constraints can be circumvented while leading to a new class of fabrics. The proposed one-step textile nanofinishing process relies on the diffusional deposition of aerosol NPs onto textile fibers. As proof of this concept, we deposit Ag NPs onto a range of textiles and assess their antimicrobial properties for two strains of bacteria (i.e., Staphylococcus Aureus and Klebsiella Pneumoniae).The measurements show that the logarithmic reduction in bacterial count reaches ca. 5.5 (corresponding to a reduction efficiency of 99.96%) when the Ag loading is one order of magnitude less (10 ppm; i.e., 10 mg Ag NPs per kg of textile) than in the textiles treated by traditional wet-routes. The antimicrobial activity does not increase in proportion to the Ag content above 10 ppm as a consequence of a "saturation" effect. Such low loading for

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“…Presumably, the observed strain rate [15] Zr-based Tension Yes 100 − 875 nm ∼ 100 nm Guo et al [46] Zr-based Tension Yes 100 nm -Deng et al [51] C u 51 Z r49 Tension Yes ∼ 200 nm -Luo et al [52] Al-based Tension Yes < 20 nm - dependence is stemmed from the size-dependent diffusion rate change. [53,54] A systematic study on the effect of size and strain rate on the deformation mechanism of micronanoscaled MGs pillars is carried out by Tonnies et al [55] A size-dependent critical diameter for the deformation mechanism transition is revealed and a size-strain rate deformation map is proposed.…”

Section: Strength-size Relationshipmentioning

confidence: 99%

Mechanical Behavior of Micronanoscaled Metallic Glasses

Tian

Wang

Shan

2016

Materials Research Letters

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In this paper, research on the mechanical behavior of micronanoscaled metallic glasses (MGs) is reviewed, with an emphasis on works achieved through in situ transmission electron microscope. It was found that the strength of micronanoscaled MGs has a nonlinear dependence on sample size. Corresponding to the transition of size-dependent strength, the deformation mechanism of MGs changes gradually from brittle to ductile with the critical transition size being affected by strain rate, e-beam irradiation and thermal history of the sample. Besides monotonic loading, the mechanical behaviors of MGs in response to cyclic loadings and fatigue tests are also reviewed. Keywords: Metallic Glasses, Micronanoscaled, Plasticity, Strength, Cyclic LoadingIntroduction Metallic glasses (MGs), also known as amorphous metals, are materials composed of metal components but without crystalline structure.[1-3] The lack of long-range order, that is, atoms do not register in periodic lattice sites, renders MGs unique in mechanical behaviors. [4][5][6][7] Unlike crystalline metals, MGs do not have dislocation or deformation twinning as plastic carriers. When the applied mechanical load exceeds their yield strength, bulk MGs usually deform through the formation of shear band, a thin band where large shear strains localized [8], usually in a catastrophic manner. The stress level required for the nucleation and propagation of shear band is much higher than that for dislocations or twins in bulk crystalline materials, usually on the GPa level. Without early yielding, the measured elastic limit for bulk MGs can be up to 2% [4,9], much larger than their crystalline counterparts. Even though the brittleness and high cost limit the commercialization of bulk MGs, recent studies [10][11][12] demonstrated that micronanoscaled (refer to samples with their size ranged from 10 nm to 10 μm [13]) MGs own outstanding strength and reasonable plastic deformability which make them attractive for applications in Micro/Nano electro-mechanical systems (M/NEMS). Consequently, a systematic study of the mechanical properties of

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Liquid-like pseudoelasticity of sub-10-nm crystalline silver particles

Cited by 268 publications

References 38 publications

Memristors with diffusive dynamics as synaptic emulators for neuromorphic computing

Memristors with diffusive dynamics as synaptic emulators for neuromorphic computing

Scalable and Environmentally Benign Process for Smart Textile Nanofinishing

Mechanical Behavior of Micronanoscaled Metallic Glasses

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