Thermal‐Responsive Polyoxometalate–Metalloviologen Hybrid: Reversible Intermolecular Three‐Component Reaction and Temperature‐Regulated Resistive Switching Behaviors

Abstract

The development of new-type memristors with special performance is of great interest. Herein, an inorganicorganic hybrid crystalline polyoxometalate (POM) with usual dynamic structures is reported and used as active material for fabricating memristor with unique temperature-regulated resistive switching behaviors. The hybrid POM not only exhibits tunable thermochromic properties, but also thermalinduced reversible aggregation and disaggregation reactions, leading to reversible structural transformations in SCSC fashion. Further, the memory device using the hybrid POM as active layer exhibits uncommon performance, which can keep resistive switching silent in the low temperature range of 30-150 8C, but show nonvolatile memory behavior in the high temperature range of 150-270 8C. Particularly, the silent and working states at three special temperatures (30, 150 and 270 8C) can be monitored by chromism. The correlation between structure and resistive switching property of the material has been discussed. The work demonstrates that crystalline inorganic-organic hybrid POMs are promising materials for making memristors with superior performance.Memristors are leading candidates for the next generation non-volatile memory devices owing to their low power consumption, high access speed, multi-state switching and device scalability. [1][2][3][4][5][6][7] The development of memristors with high performance and reliability under special/harsh environments is in great demand so that they can be applied in many promising fields, such as aerospace, geothermal, oil and gas industries. [8] In the past few decades, great efforts have been paid to improve the switching performance of memristors at high temperatures because the working mechanisms of memory devices, including filamentary conduction, space charge trapping, valence and conformation changes and

Applications of Viologens in Organic and Inorganic Discoloration Materials

“…Zheng's group reported POM-based inorganic-organic hybrid crystalline materials with generally dynamic structures. [97] Its structure contains an anionic 1D POM-metallic viologen chain, which is formed by the metal Co II substituted Co 4 (H 2 O) 2 (B-α-PW 9 O 34 ) 2 )] 10À anions linked by a Co 3 -complexes. The isolated 1D chain [Co(H 2 O) 6 ] 2 + interacts with bpdo via hydrogen bonding interactions (Figure 8m).…”

“…[97] (j) Diagram of ITO/1/Ag device. [97] (k-l) I-V curves of ITO/1/Ag device for ten cycles at 150 °C or 270 °C. [97] Reprinted with permission from Ref.…”

Insights from Adsorption and Electron Modification Studies of Polyoxometalates on Surfaces for Molecular Memory Applications

“…Furthermore, not only must electron transport properties via application of an external potential be considered, but also stimulation by light and temperature effects may influence the switching properties of POMs. A recently presented cobalt-based POM–metalloviologen hybrid offered, for example, nonvolatile resisting switching properties only at elevated temperatures …”

“…A recently presented cobalt-based POM− metalloviologen hybrid offered, for example, nonvolatile resisting switching properties only at elevated temperatures. 75 Finally, it should also be noted that POMs are interesting not only for usage in memristive memories but due to their distinct electron absorption capabilities also for new applications in the field of classical charge-based memories. For instance, the integration of a Wells−Dawson-POM archetype with an embedded [(Se IV O 3 ) 2 ] 4− unit as an oxidizable dopant into the floating gate of a metal−oxide− semiconductor (MOS) flash memory cell may lead to a new type of flash memory called "write-once-erase".…”

Redox-active and Brønsted basic dual sites for photocatalytic activation of benzylic C–H bonds based on pyridinium derivatives

“…The formation of deeply colored radical species as one-electron reduction products endows this family with appealing applications in photoelectrochromic devices, 33 switchable materials, 34 molecular motors, 35 energy-storage materials, 36 etc. [37][38][39][40] By using pyridinium-mediated electron transfer and energy transfer for the activation of molecular oxygen to produce • O 2 − (superoxide radical) and 1 O 2 (singlet oxygen), we have achieved selective photocatalytic oxidation of alcohols to ketones or aldehydes using air at room temperature without any metals and co-catalysts/additives. 25 In continuation of our goal to develop sustainable protocols for green organic synthesis by using pyridinium-based photocatalysts, we find that the pyridinium deriva-tive containing a neutral N-heterocyclic unit may provide a concerted pathway for C-H bond activation through protoncoupled electron transfer (PCET) 26 based on the combination of the strong electron-accepting ability of the pyridinium units and Brønsted basic site of the N-heterocyclic unit (Scheme 1), thus promoting hydrogen abstraction that is an essential step for activating the C-H bond.…”