一种新型的有机电双稳薄膜及其极性记忆效应

报道了一种新的高稳定的有机分子（SCN）可以和铜构成具有电双稳态特性的金属有机络合物。由这种材料制成的薄膜，在室温6V电压作用下可以从高阻态转变成低阻态，其跃迁时间小于20ns，并具有极佳的热稳定性。因此可望用于制作电子器件，如一次写入存储器（WORM）等。进一步的研究还发现，在适当的工艺条件下，SCN能够与Cu和Al一起构成Cu-SCN-Al结，这种结具有极性记忆效应，即只能被单向驱动。     

有机纳米整流器的STM研究

金属有机络合物Ag TCNQ的薄膜在STM针尖电场的作用下 ,当电压达到某一阈值后可以从高阻态跃迁至低阻态。在一定的条件下 ,在低阻态的保持时间很短 ,且高低阻态间的转换可以重复。由于它们都是有机材料 ,根据这种特性 ,提出了一种新型有机纳米整流器的设想 ,并成功地制作了输出可控的有机纳米整流器的原型。     

一种电可擦写可读出的有机薄膜存储器件

报道一种具有可逆电双稳特性的有机薄膜存储器件.器件采用三明治夹层结构Ag/DBCN/Al,DBCN为有机分子材料的简称.这种薄膜器件可以通过改变外加电场的大小来控制所处的状态,表现出高电压区(＞6V)为高阻态(＞106Ω),低电压区(1～2V)为低阻态(～103Ω)的特性,外电场消失时其状态能够长时间保持稳定(超过3个月),还可以用小电压脉冲信号(＜0.5V)来读取其状态信息.此外还发现该器件具有良好的耐热稳定性.     

一种可擦写可读出的分子基电双稳器件

报道一种可以连续可逆转换的分子基电双稳薄膜器件Ag/BN4/Al,其中BN4为分子材料.该器件在较强电场(约为6 V)作用下表现为高阻态("0"态),阻值大于105 Ω;而在较弱的电场(＜2 V)作用下则为低阻态("1"态)，阻值约为102 Ω，两种状态的阻抗比103～105.改变外加电场的大小，器件的两种状态随之发生多次转变，转换次数可超过103.高阻态和低阻态的状态信息还可以用一个小电压脉冲(0.2 V)来读取.这种简单器件具有可擦写可读出功能，可用于制作分子基开关和分子基存贮器.     

有机纳米整流器的STM研究

金属有机络合物Ag-TCNQ的薄膜在STM针尖电场的作用下，当电压达到某一阀值后可以从高阴态跃迁至低阻态。在一定的条件下，在低阻态的保持时间很短，且高低阻间的转换可以重复。由于它们都是有机材料，根据这种特性，提出了一种新型有机纳米整流器的设想，并成功制作了输可控的有机纳米整流器的原型。     

单一有机材料PAN的电双稳特性及其应用

发现单一有机材料 1 (2吡啶偶氮 ) 2 萘酚 (PAN)在室温下即具有电双稳特性。在真空中制成的薄膜 ,两边在数伏电压的作用下 ,即可从高阻态变为低阻态 ,且跃迁时间小于 10ns。由此可作为功能材料用于非易失性存贮器和过电压保护器等     

一种可擦写可读出的有机电双稳器件

本文报道一种可连续可逆转换的有机电双稳薄膜器件,Al/TPR-1/Al/TPR-1/Al,其中TPR-1为有机分子材料,利用真空蒸发-紫外原位聚合的方法制作成膜.在器件中,两层交联的有机物中间夹一层很薄的铝膜.该器件在较低电压(＜3V)作用时呈现高阻状态,阻值大于108Ω;而在较高电压(约5V)作用时,则为低阻态,阻值约为105Ω.两种状态的电阻值比为103～105.高低阻态均可通过一个较小的电压(1V)读出,并且低阻态可以用反向电压"擦除",回到高阻.     

纳米晶粒Ag—TCNQ络合物薄膜的制备及电双稳特性

以物理气相沉积方法将TCNQ和Ag制备的金属有机络合物薄膜，在一定的工艺条件下可做到构成薄膜的晶粒直径为40nm左右，粗糙度也为纳米量级，同时在大气及室温条件下，在STM电场的作用下薄膜可从高阻态转换为低阻态作用点的直径为为70nm.     

纳米晶粒Ag-TCNQ络合物薄膜的制备及电双稳特性

以物理气相沉积方法将TCNQ和Ag制备的金属有机络合物薄膜,在一定的工艺条件下可做到构成薄膜的晶粒直径为40nm左右,粗糙度也为纳米量级。同时在大气及室温条件下,在STM电场的作用下薄膜可从高阻态转换为低阻态,作用点的直径约为70nm。     

具有非易失存储功能的可逆有机电双稳器件

报道一种能够在室温下具有可逆电双稳特性，并实现非易失信息存储功能的有机薄膜器件。器件为简单的三层结构，Al/HPYM/Ag，HPYM为一种有机分子材料，通过真空热蒸发法制成薄膜作为信息存储介质。该器件可通过正向及反向电压脉冲的激发而实现高阻态（“0”态）、低阻态（“1”态）的转变，相当于信号的写入和擦除。当外电场撤除时，其状态信息可以长时间保持，并且被小电压脉冲读取，两种导电态的阻值比约为10^5。     

New charge-transfer salts for reversible resistive memory switching

We found novel organic charge-transfer salts that exhibit reversible resistive memory switching phenomena. Homogeneous layers of these complexes can be easily fabricated using solution processing. The copper-2,3-dichloro-5,6-dicyano-p-benzoquinone complex was investigated in more detail. Devices made of this complex can be reversibly switched between a high and a low resistance state by applying voltage pulses as short as 1 micros. The memory states remain stable for more than 15 h without an electricity source.     

Tunable photochromism of spirobenzopyran via selective metal ion coordination: an efficient visual and ratioing fluorescent probe for divalent copper ion

In the present paper, a new spirobenzopyran derivative was synthesized and applied in simultaneously colorimetric and fluorescence ratiometric detections of Cu2+. In contrast to the virtually photochromic character of the common spirobenzopyrans in most organic solvents, this spirobenzopyran is colorless in organic aqueous solution even irradiating by ultraviolet light. The formation of red merocyanine in an ethanol-aqueous solution is only induced by Cu2+ coordination. Furthermore, the closed form of the spirobenzopyran is highly fluorescent. Upon complexation with Cu2+, it displays not only decreasing in the initial fluorescence emission band but also appearing in a new emission at long wavelength. Thus, the Cu2+ quantitative measure can be achieved by fluorescence ratiometry. With the optimum conditions described, the Cu2+ concentration can be determined from 5.13 x 10(-7) M to 3.81 x 10(-4) with a detection limit of 1.06 x 10(-7) M. Both the color and the fluorescence changes of the spirobenzopyran are extremely specific for Cu2+ over biologically relevant substrates, which meet the selectivity requirements for biomedical application. Serum divalent copper values were determined using this spirobenzopyran, which fell into the normal range of the content reported in the literature and were in good agreement with those obtained by atomic absorption spectroscopy. The combined data from fluorescence titrations and 1H NMR measurements indicate that the new emission of the spirobenzopyran generated by Cu2+ is the result of the metal-induced ring opening and conformation restriction by Cu2+ liganding with the opened merocyanine form and the subsequent reduction of the intramolecular charge transfer of the merocyanine.     

Green strategy of scaleably synthesizing copper nanocomposites with remarkable catalytic activity for wastewater treatment

The functional copper nanocomposites (Cu NCs) have received increasing attention in the environmen-tal catalysis application for wastewater treatment due to their superior catalytic activity and reactivity.However,overcoming the pH limitations towards the neutral and alkaline wastewater remains a tricky challenge.In this work,we demonstrate a green strategy to synthesize Cu NCs with coexistence of active Cu,Cu2O and ZrO2 by self-propagating combustion of metallic glassy ribbons,which exhibit the extremely superior catalytic performance for degradation reaction,providing full conversion of organic dyes com-pletely to the environmental friendly small species (efficiency ＞ 99％) under acidic,neutral and alkaline conditions.Compared with all other catalysts developed thus far,the novel Cu NCs catalysts with more active sites present much enhanced catalytic capability of degradation efficiency without the use of any chemical reagents for neutral and alkaline organic dye solutions.The possible decomposition pathways of organic dyes for different pH systems were systematically investigated.More importantly,the two kinds of catalytic mechanism related to high reactivity of nanoscale Cu/Cu2O and strong oxidizing capability of activated.OH/·O2-radicals can also be successfully confirmed under different pH conditions.The green synthetic approach can be extended to design the various M-based nanocomposites (M =Fe,Co,Ni,Ag,Pd) as efficient catalysts for the functional applications of many chemical reactions.     

Double-hydrophilic block copolymer nanoreactor for the synthesis of copper nanoparticles and for application in click chemistry

Ultrasound (US), a nonconventional energy source, has become a very popular and useful technology in organic chemistry. Several examples of US-assisted reaction have indicated that high yields and short reaction times are reasonable, and applications of this energy transfer process on click reactions have been published. Stable, water-soluble copper nanoparticles (Cu NPs) were synthesized using a double-hydrophilic block copolymer as a template. The prepared Cu NPs were effective as catalysts for the [3+2] cycloaddition of azides with terminal alkynes to provide products in good yields and with high regioselectivity. An environment-friendly process of synthesizing regioselective triazoles was developed from a variety of azides with terminal alkynes, in which the water-soluble Cu NPs were utilized, under 10 min sonication. The Cu NPs can be reused three times under the present reaction conditions, without any loss of catalytic activity. Block copolymer nanoreactors were shown to be promising in creating a number of water-soluble catalytic metal NPs for a wide variety of organic transformations.     

New Results for Superconductivity in κ-(BEDT-TTF)2Cu(NCS)2 When an Applied Magnetic Field is Aligned Parallel to the Conducting Planes

Using a Tunnel Diode Oscillator technique, we have measured the effect of a parallel magnetic field on the in-plane rf penetration depths in organic [α- (BEDT-TTF)₂NH₄Hg(SCN)₄ and κ-(BEDT-TTF)₂Cu(NCS)₂] and heavy fermion (CeCoIn₅) superconductors. We show that in this particular ge- ometry, the effects due to vortex activity are minimized. The penetration depth is then governed by the density of superconducting carriers. It is shown in many experiments including rf penetration depth measurement that α-(BEDT-TTF)₂NH₄Hg(SCN)₄ and CeCoIn₅ have s-wave and d-wave pairing symmetries, respectively. The pairing symmetry of κ-(BEDT-TTF)₂-Cu(NCS)₂, however, is still an unsolved matter, showing inconsistent results. In this paper, the penetration depth of κ-(BEDT-TTF)₂Cu(NCS)₂ is shown to be more similar to α-(BEDT-TTF)₂NH₄Hg(SCN)₄ than to CeCoIn₅, suggesting the pairing is nodeless.     

Serial vs. divergent supply chain networks: a comparative analysis of the bullwhip effect

The amplification of demand variation in a supply chain network (SCN) is a well-known phenomenon called the bullwhip effect, which creates inefficiencies due to high variation in the order quantities placed between companies, leading to a flow of a larger number of units than the actual need, increasing stock and generating stock-outs. Since this phenomenon has been recognised as one of the main obstacles for improving SCN performance, recently it has received a lot of attention by SCN managers and researchers. One of the most common simplifying assumptions in the literature is to assume that the SCN adopts a serial structure. The present work addresses a comparative analysis of the bullwhip effect between a serial SCN and a more complex divergent SCN. To do so, we analyse the response of both SCNs under two different input demands: a stationary demand and an impulse demand. The results reveal that there are not significant differences in terms of bullwhip effect between both SCNs for a stationary demand. Nevertheless, we show how for a violent disturbance in customer demand there is a great different between the two SCNs.     

Light-controlled molecular resistive switching ferroelectric heterojunction

Molecular ferroelectrics have attained significant advancement as a promising approach towards the development of next-generation non-volatile memory devices. Herein, the semiconducting-ferroelectric heterojunctions which is composed of molecular ferroelectrics (R)-(−)-3-hydroxlyquinuclidinium chloride together with organic charge transfer complex is reported. The molecular ferroelectric domain provides polarization and bistability while organic charge transfer phase allows photo-induced charge generation and transport for photovoltaic effect. By switching the direction of the polarization in the ferroelectric phase, the heterojunction-based devices show non-volatile resistive switching under external electric field and photocurrent/voltage induced by light excitation, stable fatigue properties and long retention time. Overall, the photovoltaic controlled resistive switching provides a new route for all-organic multiphase non-volatile memories.     

Single‐Step Assembly of Large‐Area,Transparent Conductive Patterns Induced Through Edge Adsorption of Template‐Confined Au‐Thiocyanate

Fabrication of patterned metallic films through chemical means is a primary objective in the emerging field of “bottom‐up” lithography. We present a simple technology for generating large area, highly uniform patterns of conductive gold microwires. The approach is based upon dissolution of a gold complex, Au(SCN)₄⁻, in an organic‐solvent/water mixture and confining the solution underneath polymeric molds. We show that Au(SCN)₄⁻ undergoes spontaneous crystallization/reduction, producing metallic Au microwires tracing the contours of the templates. Importantly, no shape‐directing molecules or reducing agents are required for Au microwire formation, as the thiocyanate ligands both donate the reducing electrons as well as direct the crystallization process of the Au patterns. We demonstrate application of the new technology for creating highly transparent conductive films.     

Pseudohalide‐Induced 2D (CH3NH3)2PbI2(SCN)2 Perovskite for Ternary Resistive Memory with High Performance

Recently, organic–inorganic hybrid perovskites (OIHP) are studied in memory devices, but ternary resistive memory with three states based on OIHP is not achieved yet. In this work, ternary resistive memory based on hybrid perovskite is achieved with a high device yield (75%), much higher than most organic ternary resistive memories. The pseudohalide‐induced 2D (CH₃NH₃)₂PbI₂(SCN)₂ perovskite thin film is prepared by using a one‐step solution method and fabricated into Al/perovskite film/indium–tin oxide (glass substrate as well as flexible polyethylene terephthalate substrate) random resistive access memory (RRAM) devices. The three states have a conductivity ratio of 1:10³:10⁷, long retention over 10 000 s, and good endurance properties. The electrode area variation, impedance test, and current–voltage plotting show that the two resistance switches are attributable to the charge trap filling due to the effect of unscreened defect in 2D nanosheets and the formation of conductive filaments, respectively. This work paves way for stable perovskite multilevel RRAMs in ambient atmosphere.