Papers by Keyword: TCNQ

Abstract: Polythiophene was prepared by oxidation of thiophene. It was electronically doped with organic acceptors such as TCNE, TCNQ, DDQ, Chloranil and kI-I₂. The FTIR spectra revealed only little change of intermolecular band gap of about 0.21ev of polythiophene .However, polythiophene (pure) obtained from chemical company revealed degenerate semiconducting property. The electronic doping with the organic acceptors and kI-I₂ revealed optical properties in small polaron model in the FTIR range. Thus both non-degenerate and degenerate polythiophenes were studied with 60% doping of organic acceptors.

Abstract: The interactions of the electron donors kryptofix (K-222) with 7,7,8,8-Tetracyanoquino- dimethane (TCNQ) were studied spectrophotometrically in aceton/water at several temperatures. The UV-vis spectra of the formed molecular charge transfer (CT) complexes were recorded. The molecular structures of the CT-complexes were independent of the position of the amino group on the K-222 and were formulated as [(K-222)(TCNQ)]. A spectrophotometric method for determination of K-222 was developed and validated for the quantitative analysis of K-222 in the radiopharmaceuticals. With an internal standard, the limit of quantitation for K-222 was 2 ug/ml. This is so far the most facile method for the determination of K-222. Excellent linearity (RSQ = 0.9997) was obtained over the range of 2.0–31 ug/ml. Good precision and accuracy were also observed. The method is amenable to the validation of radiosynthetic methods.

Abstract: CuTCNQ is a charge transfer complex displaying resistive electrical switching when sandwiched between Cu and Al contacts. Corresponding memory cells switch from a native high resistive OFF state (HRS) to a low resistive ON state (LRS) by applying a negative voltage to the Al with respect to the Cu. Inversion of the signal polarity leads to switching from the LRS to the HRS. Typical CuTCNQ preparation occurs by a chemical reaction of a Cu substrate with TCNQ, involving (partial) corrosion of the metal. In this contribution we present electrodeposition of CuTCNQ on Au and Pt substrates, leading – in contrast to previously published dendritically crystal growth – to relatively smooth, micrometer thick layers. Corresponding large area cross-bar memory arrays (200€m by 200€m, with Al top contacts) exhibited up to several thousand write/erase cycles with an ON/OFF current ratio of 5-10. Furthermore preliminary growth experiments with blanket tungsten bottom contact Metal–Oxide–Semiconductor (CMOS) wafers with 250 nm diameter contact holes showed that electrodeposition is a suitable method for CuTCNQ integration.