Single Gold Atom Containing Oligo(phenylene)ethynylene: Assembly into LB Films and Electrical Characterization
Single Gold Atom Containing Oligo(phenylene)ethynylene: Assembly into LB Films and Electrical Characterization
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DOI：
10.1021/jp510078w
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发表时间：
2015-01-08
影响因子：
3.7
通讯作者：
Cea, Pilar
中科院分区：
文献类型：
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作者：
Balesteros, Luz M.;Martin, Santiago;Cea, Pilar
用朗缪尔-布洛吉特方法制备了分子骨架上含有金原子的低聚(亚苯基)乙炔衍生物[2-isocyano-1，3-dimethylbenzene][4-(4′-aminophenylethynyl)phenylethynyl]gold，1，的单分子膜，以研究通过在其结构中引入金中心来调节其电学性质的方法。1的朗缪尔单分子膜在空气-水界面的UV-Vis反射光谱表明，相邻分子之间强烈的亲金相互作用随着压缩而增加。通过将1的朗缪尔膜转移到固体衬底上，可以很容易地制备出单分子层的朗缪尔-布洛杰特(LB膜)膜。石英晶体微天平(QCM)实验结果表明，形成了表面复盖率较高的单层LB膜。原子力显微镜(AFM)对薄膜的形貌进行了分析，结果表明薄膜形成了均匀的膜层，最佳的表面迁移压力为6mN·m-1。循环伏安法证实了薄膜的均一性和完整性，这些结构良好的单分子膜对金电极的有效阻挡作用为1。用扫描隧道显微镜(STM)采用“针尖接触”的方法研究了1LB膜的电学性质。观察到了隧道结(Simmon型行为)I−V曲线的特征形状，对伪线性(欧姆)区的分析给出了电导值G=3.9×10-5G0，这对于OPE导数来说是相对较高的，可能表明金属原子在线状系统中的有利作用.
Monomolecular films of an oligo(phenylene)ethynylene, OPE, derivative [2-isocyano-1,3-dimethylbenzene][4-(4′-aminophenylethynyl)phenylethynyl]gold,1, containing a gold atom in the molecule backbone have been prepared by the Langmuir–Blodgett (LB) method in order to study how the electrical properties can be modulated in monolayers of OPEs by incorporation of a gold center in their structures. UV–vis reflection spectra of Langmuir monolayers of1at the air–water interface reveal strong aurophilic interactions between neighboring molecules that increase upon compression. Monolayer Langmuir–Blodgett (LB) films were readily fabricated by the transfer of Langmuir films of1onto solid substrates. Quartz crystal microbalance (QCM) experiments conclusively demonstrate formation of monolayer LB films with a high surface coverage. The morphology of these films was analyzed by atomic force microscopy (AFM), revealing formation of homogeneous layers with an optimum surface pressure of transference of 6 mN·m–1. Film homogeneity and integrity was confirmed by cyclic voltammetry, with efficient blocking of gold electrodes by these well-formed monolayers of1. The electrical properties of LB films of1were investigated by scanning tunneling microscopy (STM) using a “tip-to-contact” method. Characteristic shape for a tunneling junction (Simmon’s type behavior)I−Vcurves were observed, with analysis of the pseudolinear (ohmic) region giving a conductance valueG= 3.9 × 10–5G0, which is relatively high for an OPE derivative and may indicate a beneficial role of metal atom incorporation within the wire-like system.