Flexible Transparent Organic Artificial Synapse Based on the Tungsten/Egg Albumen/Indium Tin Oxide/Polyethylene Terephthalate Memristor

Abstract

As artificial synapses in biomimetics, memristors have received increasing attention because of their great potential in brain-inspired neuromorphic computing. The use of biocompatible and degradable materials as the active resistive layer is promising in memristor fabrication. In this work, we select egg albumen as the resistive layer to fabricate flexible tungsten/egg albumen/indium tin oxide/polyethylene terephthalate devices, which can operate normally under mechanical bending without significant performance degradation. This proposed memristor device exhibits a transparency of more than 90% under visible light with a wavelength range of 230–850 nm. Moreover, by changing amplitudes of pulse voltage instead of intervals, paired-pulse facilitation can be transmitted to paired-pulse depression, which can faithfully mimic dynamical balance of Ca2+ concentration shaped by voltage-sensitive calcium channels. The device resistance can be modulated gradually by applied pulse trains to mimic certain neural bionic behaviors, including excitatory postsynaptic current, short-term plasticity (STP) and long-term plasticity (LTP), and transitions between STP and LTP. The reasons behind these behaviors are analyzed through power consumption calculation. Excellent biosimulation characteristics have been demonstrated in this egg albumen-based memristor device, which is desirable in biocompatible and dissolvable electronics for flexible artificial neuromorphic systems.

Recent advances in organic‐based materials for resistive memory applications

“…Yan et al proposed a highly transparent and flexible memristor device, which selected egg albumen as the active element (Figure 15A). 50 This albumen‐based memristor device possessed outstanding memristive property (Figure 15B), which could mimic certain neural bionic behaviors by applying pulse trains (Figure 15C), proving natural low‐cost materials applicable for intelligent artificial synaptic systems. Albumen‐based, large‐area paper substrates with both robust physical flexibility and excellent electrical properties were fabricated by Zhou et al (Figure 15D) via a simple thermal and chemical reaction process 131 .…”

“…Recently, there is an emerging demand on the development of bio‐based materials for resistive memory devices. Compared with inorganic materials, bio‐based materials are renewable and environment friendly and usually exhibit superior biocompatibility, biodegradability, sustainability, and flexibility 39,50,131‐141 . Many biomaterials can be easily extracted from natural abundant resources and hence are of low expenditure.…”

“…C, Current vs time in device measurement under successive 50 pulses. Reproduced with permission 50 . Copyright © 2019, American Chemical Society.…”

Flexible Neuromorphic Electronics for Computing, Soft Robotics, and Neuroprosthetics

“…[145,[162][163][164][165][166] Biomaterials are abundant, renewable, easily processed, and lightweight, so many have been investigated for use in fabrication of biocompatible neuromorphic electronics. [167][168][169][170] For example, chitosan [57,64,126,166,171] and cellulose [66] have been used as ion conductors of gate insulators in 3-T devices, and collagen, [4] albumen, [170] lignin, [75] CιC, [172] and Ag-doped chitosan [141] were used as active layers in 2-T devices.…”

Flexible and Insoluble Artificial Synapses Based on Chemical Cross‐Linked Wool Keratin

“…In addition, the change of Ag electrode to tungsten electrode does not show similar good performance ( Figure S7, Supporting Information), indicating that the good performance of Ag/keratin/ITO/PEN device is related to the diffusion of Ag ions. [5,[37][38][39] Another remarkable characteristic of the cross-linked wool keratin based memristors is water insolubility: the switching resistance between the on and off states only fluctuated in a small range after immersion in water for 0-48 h (Figure 2c). The modified memristors maintain reliable and reproducible performance even after a long period of water soaking.…”