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Liu H.,Soochow University of China | Zhuang H.,Soochow University of China | Li H.,Soochow University of China | Lu J.,Soochow University of China | Lu J.,State Key Laboratory of Treatments and Recycling for Organ
Chemistry - An Asian Journal | Year: 2014

We report the synthesis of two imidazole-based small molecules with different planarity of terminal aromatic rings and their application in memory devices with a sandwich configuration. The optical, electric, and the on-based device performances were systematically investigated. Surprisingly, the device based on BT-PMZ exhibited volatile static random access memory (SRAM) behavior, whereas that based on BT-BMZ showed nonvolatile write-once-read-many-times (WORM) behavior. Further studies on the film morphology and the molecular electronic structure were carried out to investigate the underlying mechanism for the large difference in their performance. Moreover, the performance of the device that incorporates a LiF buffer layer (5nm) embedded at the interface between the BT-BMZ active layer and the Al top electrode as well as that of the device with a cold-deposited top electrode of mercury droplet was further investigated. At that point a dramatic change in memory performance of the devices from the WORM to SRAM type was observed. The intrinsic volatile SRAM performance for the two molecules results from the moderate electron-withdrawing strength of the acceptor moieties and thus weak trapping of the charge carriers. Down memory lane: Memory devices based on two imidazole derivatives, BT-PMZ and BT-BMZ (see figure), with different planarity of terminal aromatic rings exhibited volatile static random-access memory (SRAM) behavior and nonvolatile write-once-read-many-times (WORM) behavior, respectively. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


He D.,Soochow University of China | Zhuang H.,Soochow University of China | Liu H.,Soochow University of China | Li H.,Soochow University of China | And 2 more authors.
Journal of Materials Chemistry C | Year: 2013

Ion-doped poly(4-vinylpyridine) derivatives (P4VPCz), where in the pendant chains the electron-withdrawing pyridine moiety and acceptor carbazole moiety are linked by a flexible alkyl spacer were designed and synthesized. Sandwiched ITO/P4VPCz/Al devices, made through simple spin-coating processes have shown that they could be tuned from a binary to ternary memory performance, by increasing the carbazole content. P4VPCz2 with a 20% mole ratio of the carbazole moiety shows a binary performance according to the charge trapping of the pyridine acceptor in the polymer, while P4VPCz5 which contains a 50% mole ratio of carbazole in the pendant chains, exhibits a ternary data storage ability, probably induced by double mechanisms (i.e. a conformational change and charge trapping). Interestingly, as the carbazole mole ratio reached 80%, the polymer P4VPCz8 has a high conductivity state, with no switching behavior, because of the large amount of doped ions improving the charge transfer mobility. Thus, we hope can offer a guideline to achieve a high-performance multilevel memory material, via combining different mechanisms as well as doping ions. © 2013 The Royal Society of Chemistry.


Qiu X.,Soochow University of China | Li N.,Soochow University of China | Li N.,State Key Laboratory of Treatments and Recycling for Organ | Ma X.,Soochow University of China | And 7 more authors.
Journal of Environmental Chemical Engineering | Year: 2014

A new acrylic ester-based crosslinked copolymer (BMS-resin) was prepared via traditional suspension polymerization and used as an adsorbent to remove phenol at a certain super-high concentration of 93,000 mg/L. Effects of pH and temperatures were investigated and the results showed that more favorable adsorption was achieved in acidic solution while the adsorption process was hardly affected by the temperature. Comparing with activated carbon fiber (ACF) and one of the typical macroporous resin (XAD-4), the BMS-resin is more efficient and its adsorption capacity is much higher than other two porous adsorbents under the high initial concentrations. Especially at the concentration of 93,000 mg/L, a great adsorption amount up to 1000 mg/g was achieved. The adsorption of phenol by BMS-resin is attributed to the hydrogen bonding formed between the ester groups on the surface of resin beads and the hydroxyl groups of phenol molecules, which is closely related to the initial phenol concentration and it is different to the physical adsorption owing to the large specific surface area of the porous adsorbents. The adsorption isotherms and adsorption kinetics of BMS-resin were investigated and the results also verified the above adsorption mechanism. In addition, the saturated resin was easy to get an entire regeneration with unchangeable capacity in the reusage. © 2013 Elsevier Ltd. All rights reserved.


Xing Q.,Soochow University of China | Li N.,Soochow University of China | Li N.,State Key Laboratory of Treatments and Recycling for Organ | Chen D.,Soochow University of China | And 7 more authors.
Journal of Materials Chemistry B | Year: 2014

Herein, light-responsive nanocarriers based on hollow mesoporous silica (HMS) nanoparticles modified with spiropyran-containing light-responsive copolymer (PRMS-FA) were fabricated via a simple self-assembly process. HMS modified with long-chain hydrocarbon octadecyltrimethoxysilane was an ideal base material owing to its good biocompatibility and drug capability. The spiropyran-containing amphiphilic copolymer could shift its hydrophilic- hydrophobic balance to become hydrophilic upon UV (λ = 365 nm) irradiation and then break away from the hydrophobic surface of the HMS core, followed by the uncaging and release of the pre-loaded anticancer drug. Simultaneously, the fluorescence resonance energy transfer (FRET) process based on the structural transformation of PRMS-FA was observed, which could act as a real-time monitor for the light-controlled drug release. Our model experiments in vitro tested and verified that this composite nanocarrier has good biocompatibility, active tumour targeting to the folate receptor over-expressed in tumour cells, is non-toxic to normal cells and that light-controlled drug release with real-time monitoring can be achieved. © 2014 The Royal Society of Chemistry.

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