Fabrication of human-like intelligent tactile sensors is an intriguing challenge for developing human–machine interfaces. As inspired by somatosensory signal generation and neuroplasticity-based signal processing, intelligent neuromorphic tactile sensors with learning and memory based on the principle of a triboelectric nanogenerator are demonstrated. The tactile sensors can actively produce signals with various amplitudes on the basis of the history of pressure stimulations because of their capacity to mimic neuromorphic functions of synaptic potentiation and memory. The time over which these tactile sensors can retain the memorized information is alterable, enabling cascaded devices to have a multilevel forgetting process and to memorize a rich amount of information. Furthermore, smart fingers by using the tactile sensors are constructed to record a rich amount of information related to the fingers’ current actions and previous actions. This intelligent active tactile sensor can be used as a functional element for artificial intelligence.

We describe the design principles and fabrication of Ag honeycomb mesh as a transparent conductive electrode using a polystyrene (PS) sphere template. Monolayers of PS spheres with different diameters, such as 600 nm, 3 μm, and 10 μm, are studied as templates to form Ag mesh with high transmittance. Since the parasitic Ag islands degrade the transmittance, both heat pretreatment and wet etching are used to control the area covered by parasitic Ag islands. The trade-off between transmittance and conductivity forces us to use larger diameter PS spheres. Ten-micron PS spheres are chosen as the template for the PS sphere monolayer, and heat pretreatment and Ag wet etching are used to demonstrate that the Ag honeycomb mesh transparent electrodes have high performance. The transmittance and the sheet resistance are 83% and 20 Ω/sq, which are comparable to commercial ITO electrodes.

No abstract

No abstract

Biosynaptic devices based on chicken egg albumen (ceA):graphene quantum dot (GQD) hybrid nanocomposites were fabricated to achieve stable synaptic behaviors. current-voltage (i-V) curves for the biosynaptic devices under consecutive negative and positive voltage sweeps showed clockwise pinched hysteresis, which is a critical feature of a biological synapse. The effect of the GQD concentration in the ceA layer on the device performance was studied. the retention time of the biosynaptic devices was relatively constant, maintaining a value above 10 4 s under ambient conditions. the carrier transport mechanisms of the biosynaptic devices were described and analyzed on the basis of the slopes of the I-V curves and their fittings.Due to the limitation on the speed of data transfer between the memory and the central processing unit, neuromorphic computing is faced with a bottleneck when the von Neumann computing architecture is used 1,2 . The use of nanoscale integrated circuitry based on a biomimetic brain to operate a neuromorphic system is an emerging research field because such platforms offer high-speed processing and improved energy efficiency. These demands have prompted the development of two-terminal memristors as promising candidates for artificial synapses because they can emulate synaptic plasticity with low power consumption. Many two-terminal synaptic devices are required, for reduced production cost, to mimic the complex human brain 2-6 .Nowadays, various oxide-based materials have been reported as components for resistive switching devices. The resistive switching mechanism of oxide-based devices is observed in the formation and the rupture of conducting filaments in the dielectric due to the application of an electrical pulse 7-10 . In addition, the memristors fabricated with organic materials are based on the resistive switching mechanism. The synaptic characteristics of memristors fabricated using organic/inorganic hybrid nanocomposites have been intensively investigated because such devices offer the advantages of simple fabrication, low cost, high flexibility, and low power consumption. When synaptic devices are fabricated utilizing inorganic/organic nanocomposites, matrix materials with charge-storage capability are typically deposited by using a spin-coating method [11][12][13][14] .Recently, a variety of emerging materials have been introduced to implement artificial neurons and artificial synapses 15,16 . Among the various biomaterials, chicken egg albumen (CEA) has been extensively used for potential applications in memristive devices, transistors, and synaptic devices 17-21 . CEA has recently been considered as a novel candidate owing to its promising applications in devices with human-friendly properties and in next-generation devices. The proteins in albumen will denature when a large amount of heat energy is applied in the devices. The denaturation of the proteins in CEA reduces the probability of oxygen scattering and changes the paths of oxygen diffusion, resulting in an increase in the p...