Electron transport in networks of gold nanoparticles connected by oligothiophene molecular wires
作者:Shin-ichi Taniguchi、Masaru Minamoto、Michio M. Matsushita、Tadashi Sugawara、Yuzo Kawada、Donald Bethell
DOI:10.1039/b604732g
日期:——
Network structures made of π-conjugated molecular wires of oligothiophene 3mer, or 9mer carrying thiol groups at α,ω-positions, and gold nanoparticles with average diameter of 4 nm were prepared on interdigitated gold electrodes. Observation of the resultant assemblies by means of FE-SEM and TEM revealed that the gold nanoparticles were connected by π-molecular wires to form a network. The networks exhibited thermally activated electron transport at room temperature with activation energies of 21and 45 meV for 3mer- and 9mer-networks, respectively, and these values were almost the same as those of networks connected with non-conjugated molecules having similar lengths. However, the activation energy became very small (∼0.1 meV) at temperatures lower than 30 K and non-linear current–voltage characteristics (I
∝
V3) appeared in π-conjugated networks at 4.2 K. These results suggest that the gold nanoparticles in the networks work as Coulomb islands and the temperature-independent behavior at lower temperatures can be interpreted in terms of a co-tunneling mechanism.
在相互咬合的金电极上,制备了由寡噻吩 3 聚物或 9 聚物(在 α、ω 位置带有硫醇基团)的 π 共轭分子线和平均直径为 4 纳米的金纳米粒子组成的网络结构。通过 FE-SEM 和 TEM 对所制备的组件进行观察发现,金纳米粒子通过 π 分子线连接形成网络。这些网络在室温下表现出热启动电子传输,3 聚体网络和 9 聚体网络的活化能分别为 21 和 45 meV,这些数值与长度相似的非共轭分子连接的网络几乎相同。然而,在温度低于 30 K 时,活化能变得非常小(∼0.1 meV),并且在 4.2 K 时,π-共轭网络出现了非线性电流-电压特性(I∝V3)。这些结果表明,网络中的金纳米粒子作为库仑岛起作用,并且在较低温度下的行为与温度无关,可以用共隧道机制来解释。