Realizing Nonvolatile Photomemories with Multilevel Memory Behaviors Using Water-Processable Polymer Dots-Based Hybrid Floating Gates

Abstract

Photomemory with fast data transmission speed and high-energy saving capability has appeared as a novel storage device in the forthcoming era of information explosion. Recently, photoactive polymer dots (Pdots) have aroused significant research interests as biosimulated photocatalysts in energy conservation and renewable fuel industry due to their compelling properties like facile structural modification, good water dispersivity, tailorable optoelectronic properties, and high suitability for visible-light-driven processes. Given these advantages, Pdots are innovatively proposed for photomemory applications, for the first time. Herein, water-processed Pdot-based floating gates are demonstrated to realize light-erasable photomemory behaviors of the derived memory devices. Discrete conjugated Pdots embedded in an insulated polymer matrix are shown to serve as efficient charge-trapping sites to enable charge trapping/releasing through an electric field and light illumination. The structure–performance relationship of Pdot-based photomemory devices is investigated by changing the core conjugated structures of Pdots. It reveals that photomemory characteristics can be simply tuned by varying the acceptor moiety of the conjugated polymers, and forming cycloplatinated Pdots by inserting Pt complexes into the polymer backbones further converts the storage type of the derived devices from volatile memory to nonvolatile flash memory. Finally, the PFTBTAPtPy-based photomemory delivers a multilevel photorecording behavior, excellent data retention over 104 s, and reliable durability. It is worth noting that Pdot-based floating gates are fully manufactured in water without using any organic solvents, which takes a great step to the sustainable development of photomemory.

Hydrophobic and Hydrophilic Conjugated Polymer Dots as Binary Photocatalysts for Enhanced Visible-Light-Driven Hydrogen Evolution through Förster Resonance Energy Transfer

“…The specific way to solve the hydrophobicity problem of polymer photocatalysts is to convert the bulk hydrophobic polymer to form a polymer nanomicelle structure (Pdot) by employing an amphiphilic polymer including, polystyrene-poly­(ethylene glycol)-carboxyl (PS-PEG-COOH) and/or sodium dodecyl sulfate (SDS). − Advantages of the Pdot structure provide a large interface between the photocatalyst and water, and the small Pdot particles can shorten the exciton diffusion length, thereby enhancing intermolecular charge transfer and photocatalytic efficiency. − A few recent studies have succeeded at integrating different hydrophobic polymers (as binary and ternary Pdots) to create heterojunction Pdot photocatalysts exhibiting considerably enhanced photocatalytic activity for H 2 production. ,− In most of these studies, the Pdot structures were prepared using common nonconjugated amphiphilic polymers. The Cooper group reported that most of the nonconjugated amphiphilic polymers have a negative effect on the HER of the Pdot photocatalysts .…”

A brief review on device operations and working mechanisms of organic transistor photomemories

“…On the other hand, such a breakthrough concept to store multibit per cell of memory devices may solve the addressed issue and can be practically employed in the current technology. 19,24,83,100–109 To achieve this purpose, a photonic memory device could generate distinguishable memory states in between the highest and lowest drain output current by precisely controlling the charge injection or the elimination rate under various device operations (gate bias strength, light intensity, and/or bias/exposure times) as discussed previously. In this regard, the number of trapped charges within the trapping sites will be responsible for the varied built-in potentials as well as the magnitude of the drain output current in a non-volatile way.…”

Functional Materials Based on Cyclometalated Platinum(II) β-Diketonate Complexes: A Review of Structure–Property Relationships and Applications

“…It was also shown that the covalent linking strategy is better in terms of toxicity reduction as it poses less side effects than the system containing Pt nanoparticles into a solution system. Some other reports are also available on the applications of cyclometalated Pt(II) complexes in the area of data security storage [ 96 ], nonvolatile photomemories [ 97 ], NLOs [ 98 ], light electrochemical cells [ 63 ], etc. For example, it has been reported that one of the isomers of complex 62 ( Figure 16 ) shows responsiveness (luminescence switching) against ethanol vapor in a ground state [ 96 ].…”