Natural-Casein-Based Biomemristor with Pinched Current-Voltage Characteristics.

A biomaterials based memristor is of great interest for applications in the environment and human friendly electronic systems. Although a pinched current-voltage (I-V) characteristic is a signature of Chua's memristor model, biomemristors generally exhibit nonpinched I-V response. This work reports the discovery of the pinched I-V characteristics of a natural casein-based biomemristor. Water-soluble sodium caseinate (NaCas), synthesized using natural casein that was extracted from edible animal milk, was used for the fabrication of a Al/NaCas/ITO biomemristor device. In addition to pinched I-V characteristics, the Al/NaCas/ITO device shows improved performance with a sufficiently large resistance window (∼20 times), longer retention time (∼105 s), and comparable cyclic endurance (>180 cycles), as compared with the reported biomemristors reported in the literature. A physical mechanism is proposed to explain the device characteristics.

Complementary amide-based donor-acceptor with unique nano-scale aggregation, fluorescence, and band gap-lowering properties: a WORM memory device.

Organic fluorescent semiconducting nanomaterials have gained widespread research interest owing to their potential applications in the arena of high-tech devices. We designed two pyrazaacene-based compounds, their stacked system, and the role of gluing interactions to fabricate nanomaterials, and determined the prospective band gaps utilizing the density functional theory calculation. The two pyrazaacene derivatives containing complementary amide linkages (-CONH and -NHCO) were efficiently synthesized. The synthesized compounds are highly soluble in common organic solvents as well as highly fluorescent and photostable. The heterocycles and their mixture displayed efficient solvent dependent fluorescence in the visible region of the solar spectrum. Notably, the compounds were associated through complementary NH•••O = C type hydrogen bonding, π-π stacking, and hydrophobic interactions, and thereby afforded nanomaterials with a low band gap. Fascinatingly, the fabricated stacked nanomaterial system exhibited resistive switching behavior, leading to the fabrication of an efficient write-once-read-many-times memory device of crossbar structure.

Composition-dependent nanoelectronics of amido-phenazines: non-volatile RRAM and WORM memory devices.

A metal-free three component cyclization reaction with amidation is devised for direct synthesis of DFT-designed amido-phenazine derivative bearing noncovalent gluing interactions to fabricate organic nanomaterials. Composition-dependent organic nanoelectronics for nonvolatile memory devices are discovered using mixed phenazine-stearic acid (SA) nanomaterials. We discovered simultaneous two different types of nonmagnetic and non-moisture sensitive switching resistance properties of fabricated devices utilizing mixed organic nanomaterials: (a) sample-1(8:SA = 1:3) is initially off, turning on at a threshold, but it does not turn off again with the application of any voltage, and (b) sample-2 (8:SA = 3:1) is initially off, turning on at a sharp threshold and off again by reversing the polarity. No negative differential resistance is observed in either type. These samples have different device implementations: sample-1 is attractive for write-once-read-many-times memory devices, such as novel non-editable database, archival memory, electronic voting, radio frequency identification, sample-2 is useful for resistive-switching random access memory application.