High sensitivity and wide response range artificial synapse based on polyimide with embedded graphene quantum dots

Abstract

Artificial electronic synapses are commonly used to simulate biological synapses to realize various learning functions, regarded as one of the key technologies in the next generation of neurological computation. This work used a simple spin coating technique to fabricate polyimide (PI):graphene quantum dots(GQDs) memristor structure. As a result, the devices exhibit remarkably stable exponentially decaying postsynaptic suppression current over time, as interpreted in the spike-timing-dependent plasticity phenomenon. Furthermore, with the increase of the applied electrical signal over time, the conductance of the electrical synapse gradually changes, and the electronic synapse also shows plasticity dependence on the amplitude and frequency of the pulse applied. In particular, the devices with the structure of Ag/PI:GQDs/ITO prepared in this study can produce a stable response to the stimulation of electrical signals between millivolt to volt, showing not only high sensitivity but also a wide range of “feelings”, which makes the electronic synapses take a step forwards to emulate biological synapses. Meanwhile, the electronic conduction mechanisms of the device are also studied and expounded in detail. The findings in this work lay a foundation for developing brain-like neuromorphic modeling in artificial intelligence.

N-Doped Graphene/MXene Nanocomposite as a Temperature-Adaptive Neuromorphic Memristor

“…It returns to the top electrode driven by the electric field, and the device switches to a low conductivity state because the conducting filament ruptures. Notice that the current increased from 2 nA to 3 nA in Figure a, and conductance changed from 20 nS to 25 nS in Figure b when the positive pulse switched to a negative pulse was caused by the instantaneous release of the captured charge in the hetero nanomaterial charge trapping site …”

“…Notice that the current increased from 2 nA to 3 nA in Figure 6a, and conductance changed from 20 nS to 25 nS in Figure 6b when the positive pulse switched to a negative pulse was caused by the instantaneous release of the captured charge in the hetero nanomaterial charge trapping site. 8 As the temperature gradually increases, the thermal expansion of the metal material due to Joule heat causes temperature-dependent stresses within the silver conducting filaments, making the weak parts susceptible to breakage. 64,65 With an increase in temperature, the lattice vibrations in the material also increase, leading to more frequent collisions between charge carriers and phonons.…”

“…This change is reversible and can be repeatedly erased and written. Due to the reconfigurability and adaptivity of the memristor, it can achieve spike-timing-dependent plasticity (STDP), short-term potentiation/depression (STP/STD), long-term potentiation/depression (LTP/LTD), and paired-pulse facilitation (PPF), which can be used to develop AI and neural network systems, commonly known as electrical synapses. − Electrical synapses have been widely studied to explore their potential for simulation application in neural networks, pattern recognition, and intelligent control. , …”

Recent Advances in Wearable Healthcare Devices: From Material to Application

“…PI, by incorporating different materials, is also a means of extending its scope of application. Kou et al [39] mixed graphene quantum dots into PI to construct artificial synapses with high sensitivity and a wide corresponding range, which has a promising application in wearable bio-flexible sensors. Similarly, the combination of graphene and PI is also a means of preparing wearable sensors.…”

Manufacturing of graphene based synaptic devices for optoelectronic applications

“…However, to the best of our knowledge, GNR-based synaptic device has not been experimentally demonstrated, but theoretically proposed to build nonlinear leaky integrate-and-fire spiking neuron [132]. Graphene QDs can be applied as charge trapping layer in synaptic devices [133,134]. For example, Xu et al [134] reported an electronic synapse with Al 2 O 3 /graphene QDs/Al 2 O 3 structure.…”