A Flexible Transient Biomemristor Based on Hybrid Structure HfO₂/BSA:Au Double Layers

Abstract

applied and realized in new emerging memristors (i.e., resistive switching (RS)) devices, such as spider silk, silk fibroin, and egg albumen, and have been adopted as a functional layer to prepare the memristor cell. [1,2] Biomemristors have the advantages of low costs and being environmentally friendly, and they can be used to mimic the biosynapse function or nonvolatile memory to meet the need for sustainable development of electronic devices. Because of the unique advantages and potential applicability of biomemristors, biomemristors have a wide range of applications in electronic skin, biomedical and brain chip applications. [3,4] In general, biomemristor cells must be biocompatible and for electronic applications. [5-7] However, most memristor cells are made of inorganic materials, which are brittle and incompatible without flexible and versatile functionalities. [8-10] Among these biomaterials, bovine serum doped with nanogold (BSA:Au) is a natural organic material that is environmentally friendly. However, the performance of biomemristors based on this material is not stable; switching voltage and high-and low-resistance values are still relatively scattered to some extent. Therefore, it is necessary to develop flexible biomemristors that can degrade and have stable performance and reliable repeatability. On the other hand, flexible electronic device cells have been widely explored in recent years [11] in wearable devices, foldable displays, and nonvolatile resistive random-access memory devices. Furthermore, if the functional layer possesses good water-solubility, traditional electronic devices may not pollute the environment, which is undoubtedly great progress. In this work, we prepared a biomemristor using BSA:Au as the intermediate layer. We designed a new hybrid structure and added a layer of HfO 2 between the intermediate layer and electrode to stabilize the device's relevant properties. By analyzing the switching threshold distribution of devices with and without an HfO 2 intermediate layer, we discovered that the threshold voltage and the switching speed of devices with an intermediate oxide layer become smaller and faster. It is proposed that the filament rupture/rejuvenation depends on the two-layer interface region due to different Ag + traveling speeds in these two layers. We also constructed the same structure on a polydimethylsiloxane (PDMS) flexible substrate to give the device good foldability and make it wearable. These devices also possess excellent performance in bending and folding conditions.

Research Progress of Biomimetic Memristor Flexible Synapse

“…Among electrode materials, due to their excellent mechanical properties, metals and oxides are promising flexible memristor electrode materials. Some of these metal materials have high conductivity and flexibility, such as Ti [22], Mg [23], Ag [24], and W [25]. These materials are used in the preparation of flexible memristors.…”

“…They have been used as the functional layer for the preparation of memristor units and have a wide range of applications in electronic skin, biomedicine, and brain chip applications [76]. Li et al [24] used bovine serum albumin: gold as the dielectric layer and added a layer of hafnium between the intermediate layer and the electrode to stabilize the relative performance of the device. Ag/HfO 2 /BSA:Au/Pt was prepared on a polydimethylsiloxane flexible substrate to check the functional performance of biological systems under bending conditions.…”

“…The test results show that the parameters of the device do not change much after more than 300 bends. Li et al [24] prepared an Ag/HfO 2 /BSA:Au/Pt device on PDMS flexible substrate and showed good flexibility. However, after immersing in deionized water, the entire biomolecule almost disappeared except PDMS.…”

Cellulose Nanocrystal Based Bio‐Memristor as a Green Artificial Synaptic Device for Neuromorphic Computing Applications

“…[18,[29][30][31] In this regard, Park et al [18] reported artificial synapses in lignin-based bio-memristor devices, lignin is biodegradable and the abundant renewable material extracted from plants. Li et al [32] reported a bio-memristor based synaptic device with a hybrid structure of Ag/HfO 2 /BSA:Au/Pt. They used hybrid biomaterial of bovine serum doped with nano-gold (BSA:Au) and HfO 2 double layers as insulating switching layer materials.…”

Mimicking Neurotransmitter Activity and Realizing Algebraic Arithmetic on Flexible Protein-Gated Oxide Neuromorphic Transistors

“…On the other hand, flexible electronic devices have unique mechanical properties, including foldability, extensibility, and flexibility, which have caused great changes in fields including collapsible display screens, electronic-skin devices, , wearable sensors, , and biomedicines . Additionally, new conceptual flexible neuromorphic devices have also attracted attention. − Very recently, advanced electronic platforms have been synergistically integrated with neuromorphic devices to build artificial perceptual neuromorphic platforms with the function of touch, sight, hearing, etc. ,,− Such perceptual cognitive systems would have great potential in fields including but not limited to replacement neuroprosthetics and intelligent humanoid robots. , Particularly, wearable electronic systems would be endowed with new functions when integrating flexible neuromorphic devices with signal processing functions. They would execute information processing and decoding in-situ and help improve perception accuracy and responsiveness.…”