Self-Assembled Lanthanum Oxide Nanoflakes by Electrodeposition Technique for Resistive Switching Memory and Artificial Synaptic Devices.

In recent years, many metal oxides have been rigorously studied to be employed as solid electrolytes for resistive switching (RS) devices. Among these solid electrolytes, lanthanum oxide (La2 O3 ) is comparatively less explored for RS applications. Given this, the present work focuses on the electrodeposition of La2 O3 switching layers and the investigation of their RS properties for memory and neuromorphic computing applications. Initially, the electrodeposited La2 O3 switching layers are thoroughly characterized by various analytical techniques. The electrochemical impedance spectroscopy (EIS) and Mott-Schottky techniques are probed to understand the in situ electrodeposition, RS mechanism, and n-type semiconducting nature of the fabricated La2 O3 switching layers. All the fabricated devices exhibit bipolar RS characteristics with excellent endurance and stable retention. Moreover, the device mimics the various bio-synaptic properties such as potentiation-depression, excitatory post-synaptic currents, and paired-pulse facilitation. It is demonstrated that the fabricated devices are non-ideal memristors based on double-valued charge-flux characteristics. The switching variation of the device is studied using the Weibull distribution technique and modeled and predicted by the time series analysis technique. Based on electrical and EIS results, a possible filamentary-based RS mechanism is suggested. The present results assert that La2 O3 is a promising solid electrolyte for memory and brain-inspired applications.

Synthesis of a Ag/rGO nanocomposite using Bos taurus indicus urine for nitroarene reduction and biological activity.

The present study develops a unique in situ synthesis of a catalytically and biologically active Ag/reduced graphene oxide (rGO) nanocomposite. Herein, we employed Bos taurus indicus urine to synthesize a Ag/rGO nanocomposite in an environmentally benign, facile, economical, and sustainable manner. The elemental composition analysis reveals the presence of Ag, O and C elements. The scanning electron micrograph shows the formation of spherical silver in nanoform whereas rGO is found to be flake shaped with a wrinkled nature. The synthesized nanomaterial and its composite shows a positive catalytic effect in simple organic transformation for the reduction of nitroarene compounds. Investigations were conducted into the catalytic effectiveness of the prepared nanomaterials for diverse nitroarene reduction. Then, using NaBH4 at 25 °C, the catalytic roles of Ag and the Ag/rGO nano-catalyst were assessed towards the catalytic reduction of several environmental pollutants such as 2-, 3- and 4-nitroaniline and 4-nitrophenol into their respective amino compounds. To test their catalytic performance, bio-mimetically synthesized Ag NPs were thermally treated at 200 °C and compared with the Ag/rGO nanocomposite. Furthermore, biomedical applications such as the antibacterial and antioxidant properties of the as-prepared nanomaterials were investigated in this study.