Read/write/execute: PFCF-RGO (see figure) was synthesized by the 1,3-dipolar cycloaddition reaction of azomethine ylide. The J/V curves of the ITO/RGO-PFCF/Al device clearly displayed typical bistable electrical switching and a rewritable memory effect, with a turn-on voltage of about À1.2 V and an ON/OFF current ratio in excess of 10 4 . House of FÀN: The F+NH 3 reaction was studied using a highly correlated ab-initio electronic structure theory, up to the CCSD(T)/aug-ccpVQZ level of theory. A transition state FgHgNH 2 structure with a single imaginary vibrational frequency was observed (594 i cm À1 ). The deep entrance complex and small energy barrier are consistent with an exceptionally strong inverse temperature dependence of the F+NH 3 rate constant.Chem. Asian J.

Bistable electrical conductivity switching and non-volatile memory effects were demonstrated in Al/polymer/indium-tin oxide sandwich structure devices, constructed from two poly(N-vinylcarbazole) derivatives with pendant azobenzene chromophores and terminal electron acceptor moieties (-NO 2 or -CN). Both polymers (PVK-AZO-NO 2 and PVK-AZO-2CN) exhibit write-once read-many-times (WORM) type memory effects, with low switching threshold voltages below À2 V and high ON/OFF current ratios of $10 5 -10 6 . The observed electrical bistability in both polymers can be attributed to the field-induced charge transfer interaction between carbazole electron donor and terminal electron acceptor (-NO 2 or -CN) moieties, and subsequent charge trapping at the intermediate azobenzene chromophores. The proposed switching mechanism is supported by the changes in the UV-visible absorption spectra of the polymer film upon transition from the OFF to the ON state.

A new approach on usage of S‐1‐dodecyl‐S′‐(α,α′‐dimethyl‐α″‐acetic acid)trithiocarbonate (DDAT)‐covalently functionalized graphene oxide (GO) as reversible addition fragmentation chain transfer (RAFT) agent for growing of poly(N‐vinylcarbazole) (PVK) directly from the surface of GO was described. The PVK polymer covalently grafted onto GO has Mn of 8.05 × 103, and a polydispersity of 1.43. The resulting material PVK‐GO shows a good solubility in organic solvents when compared to GO, and a significant energy bandgap of ∼2.49 eV. Bistable electrical switching and nonvolatile rewritable memory effect, with a turn‐on voltage of about −1.7 V and an ON/OFF state current ratio in excess of 103, are demonstrated in the Al/PVK‐GO/ITO structure. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011

A new soluble conjugated polymer, poly[{9-(4-methoxyphenyl)-9H-carbazole}(9,9-dioctylfluorene)(2,5-diphenyl-1,3,4-oxadiazole)] (PCFO), was synthesized through the Suzuki coupling reaction. The absolute fluorescence quantum yield of PCFO was measured using the integrating sphere of a photoluminescence spectrofluorometer, and changed from 49.1% for a dilute tetrahydrofuran solution to 16.2% for a thin film due to the existence of a strong fluorescence quenching effect in the solid state. The HOMO-LUMO bandgap (3.07 eV) calculated from the electrochemical measurement is nearly identical to the optical bandgap (3.06 eV) estimated from the ultraviolet/visible absorption onset data. This film was attached to aluminum and indium-tin oxide contacts to fabricate a memory device with typical bistable electrical switching, nonvolatile write-once read-many-times memory performance, a turn-on voltage of BÀ2.3 V and an ON/OFF ratio of B10 5 . Degradation of the current density was observed for neither the ON nor OFF states after one hundred million continuous read cycles, which indicates that both states were insensitive to read cycles. Keywords: donor-acceptor system; molecular devices; polymer memory; synthesis INTRODUCTIONPolymer memories are proposed to revolutionize electrical applications by providing extremely inexpensive, lightweight and transparent modules that can be fabricated onto plastic, glass or the top layer of CMOS hybrid integration circuits, 1,2 and have been identified as an emerging memory technology by the International Technology Roadmap for Semiconductors since year 2005. 3 Rather than encoding '0'and '1' as a charge stored in the cell of a silicon device, polymer memory stores data in an entirely different form, such as in a highand low-conductivity response to an applied voltage. 4 The molecular structure of polymers can be tailored by functionalizing them with electron donors (D) and acceptors (A) of different strengths, spacer moieties of different steric effects for the electroactive pendant groups, or nanostructured electroactive materials, to induce different memory behaviors in simple metal/polymer/metal devices. 5,6 Very recently, Liu and Chen 7 highlighted the recent developments in D-A polymers for resistive switching memory device applications including conjugated polymers, functional polyimides, nonconjugated pendent polymers and polymer composites. D/A polymer materials (usually carbazole or