Inkjet assisted fabrication of planar biocompatible memristors

Water-alcohol-TiO2 dispersions as sustainable ink

Nanocrystalline titanium dioxide (TiO₂) is a widespread multifunctional and environmentally friendly material that has numerous applications requiring micro-/nanofabrication or thin film deposition. In most cases, the fabrication of titania films can be achieved using cost-efficient solution chemistry combined with various coating or printing techniques. The practical implementation of these methods requires the preparation of a suitable ink with properly adjusted rheological properties. Conventionally, such adjustments are achieved based on TiO₂ hydrosols containing various organic surfactants and stabilizing agents. However, the use of such additives may affect the properties of the deposited functional layer, which can be crucial for electronic and optical applications. In this work, we address a comprehensive study of simple surfactant-free TiO₂ dispersion systems based on various water-alcohol solvents and demonstrate the possibility of controlling the rheological properties of the titania ink in a wide range that is suitable for several printing applications. As a particular example, we demonstrate the application of a water-i-propanol-TiO₂ dispersion as a functional ink for the offset printing of interference images.

Charge Transport inside TiO2 Memristors Prepared via FEBID

We fabricated memristive devices using focused electron beam-induced deposition (FEBID) as a direct-writing technique employing a Pt/TiO2/Pt sandwich layer device configuration. Pinching in the measured current-voltage characteristics (i-v), the characteristic fingerprint of memristive behavior was clearly observed. The temperature dependence was measured for both high and low resistive states in the range from 290 K down to about 2 K, showing a stretched exponential behavior characteristic of Mott-type variable-range hopping. From this observation, a valence change mechanism of the charge transport inside the TiO2 layer can be deduced.

Research Progress of Biomimetic Memristor Flexible Synapse

With the development of the Internet of things, artificial intelligence, and wearable devices, massive amounts of data are generated and need to be processed. High standards are required to store and analyze this information. In the face of the explosive growth of information, the memory used in data storage and processing faces great challenges. Among many types of memories, memristors have received extensive attentions due to their low energy consumption, strong tolerance, simple structure, and strong miniaturization. However, they still face many problems, especially in the application of artificial bionic synapses, which call for higher requirements in the mechanical properties of the device. The progress of integrated circuit and micro-processing manufacturing technology has greatly promoted development of the flexible memristor. The use of a flexible memristor to simulate nerve synapses will provide new methods for neural network computing and bionic sensing systems. In this paper, the materials and structure of the flexible memristor are summarized and discussed, and the latest configuration and new materials are described. In addition, this paper will focus on its application in artificial bionic synapses and discuss the challenges and development direction of flexible memristors from this perspective.

Memristive TiO2: Synthesis, Technologies, and Applications

Titanium dioxide (TiO2) is one of the most widely used materials in resistive switching applications, including random-access memory, neuromorphic computing, biohybrid interfaces, and sensors. Most of these applications are still at an early stage of development and have technological challenges and a lack of fundamental comprehension. Furthermore, the functional memristive properties of TiO2 thin films are heavily dependent on their processing methods, including the synthesis, fabrication, and post-fabrication treatment. Here, we outline and summarize the key milestone achievements, recent advances, and challenges related to the synthesis, technology, and applications of memristive TiO2. Following a brief introduction, we provide an overview of the major areas of application of TiO2-based memristive devices and discuss their synthesis, fabrication, and post-fabrication processing, as well as their functional properties.