Xiao Xiaoyin, Nagahara Larry A, Rawlett Adam M, Tao Nongjian
Department of Electrical Engineering and Center for Solid State Electronics Research, Arizona State University, Tempe, Arizona 85287, USA.
J Am Chem Soc. 2005 Jun 29;127(25):9235-40. doi: 10.1021/ja050381m.
We have studied electron transport properties of unsubstituted oligo(phenylene ethynylene) (OPE) (1) and nitro-substituted OPE (2) covalently bound to two gold electrodes. The conductance values of single 1 and 2 are approximately 13 and approximately 6 nS, respectively. In addition to a decrease in the conductance, the presence of the nitro moiety leads to asymmetric I-V characteristics and a negative differential resistance-like (NDR-like) behavior. We have altered the nitro-substituted OPE by electrochemically reducing the nitro group and by varying the pH of the electrolyte. The conductance decreases linearly with the electron-withdrawing capability (i.e., Hammett substituent values) of the corresponding reduced species. In contrast, the conductance of 1 is independent of the pH and the electrode potential.
我们研究了与两个金电极共价结合的未取代的亚苯基乙炔低聚物（OPE）（1）和硝基取代的OPE（2）的电子传输特性。单个1和2的电导值分别约为13 nS和约6 nS。除了电导降低外，硝基部分的存在还导致不对称的I-V特性和类似负微分电阻（NDR-like）的行为。我们通过电化学还原硝基和改变电解质的pH值来改变硝基取代的OPE。电导随相应还原物种的吸电子能力（即哈米特取代基值）线性降低。相比之下，1的电导与pH值和电极电位无关。
