Albrecht Tim, Guckian Adrian, Ulstrup Jens, Vos Johannes G
Department of Chemistry and Nano-DTU, Building 207, Technical University of Denmark, DK-2800 Lyngby, Denmark.
Nano Lett. 2005 Jul;5(7):1451-5. doi: 10.1021/nl050818o.
Electron transport through semiconductor and metallic nanoscale structures, molecular monolayers, and single molecules connected to external electrodes display rectification, switch, and staircase functionality of potential importance in future miniaturization of electronic devices. Common to most reported systems is, however, ultrahigh vacuum and/or cryogenic working conditions. Here we introduce a single-molecule device concept based on a class of robust redox active transition metal (Os(II)/(III)) complexes inserted between the working electrode and tip in an electrochemical scanning tunneling microscope (in situ STM). This configuration resembles a single-molecule transistor, where the reference electrode corresponds to the gate electrode. It operates at room temperature in a condensed matter (here aqueous) environment. Amplification on-off ratios up to 50 are found when the redox level is brought into the energy window between the Fermi levels of the electrodes by the overpotential ("gate voltage"). The current-voltage characteristics for two Os(II)/(III) complexes have been characterized systematically and supported by theoretical frames based on molecular charge transport theory.
电子通过半导体和金属纳米级结构、分子单层以及连接到外部电极的单分子的传输，展现出在未来电子器件小型化中可能具有重要意义的整流、开关和阶梯功能。然而，大多数已报道系统的共同特点是超高真空和/或低温工作条件。在此，我们介绍一种基于一类稳健的氧化还原活性过渡金属（Os(II)/(III)）配合物的单分子器件概念，该配合物插入到电化学扫描隧道显微镜（原位STM）的工作电极和针尖之间。这种配置类似于单分子晶体管，其中参比电极对应于栅电极。它在室温下的凝聚态（此处为水性）环境中运行。当通过过电位（“栅极电压”）使氧化还原能级进入电极费米能级之间的能量窗口时，发现开-关比放大倍数高达50。两种Os(II)/(III)配合物的电流-电压特性已得到系统表征，并得到基于分子电荷传输理论的理论框架的支持。
