Aug 01, 2011 | |
Molecular electronics: conductivity caged |
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(Nanowerk News) Like little stacks of pancakes, aromatic molecules like to line up, forming neat columns known as π-stacks. Individual π-stacks, however, are difficult to handle, and pinning down basic properties, particularly whether they act as electrical conductors or insulators, has generated decades of debate. Three research groups in Japan have now teamed up to unravel the electron transfer properties of |
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The trick to the discovery was to trap defined π-stacks within molecular cages, an idea recently developed by Makato Fujita and co-workers at the University of Tokyo. The conductivity of the stack was then measured with a scanning tunnelling microscope (STM) using a technique recently pioneered by Manabu Kiguchi and colleagues at the Tokyo Institute of Technology. Finally, the experimental results were confirmed by simulations run by Tomofumi Tada's team back at the University of Tokyo. | |
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Measuring the conductivity of a stack of aromatic molecules (green) trapped within a cage (blue). (© 2011 Wiley-VCH) | |
To measure conductance through a |
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By varying the size of the cage, the researchers could selectively change the height of the stack. As the stack grew taller, from four to six molecules high, its conductivity dropped, but by a surprisingly small degree, says Kiguchi. "We were able to precisely calibrate the electron transport distance, and demonstrate that single-molecule π-stacks exhibit good conductance with only moderate loss with increasing transport length." | |
The researchers now plan to study in more detail the nature of electron transport through the |
Source: Tokyo Institute Of Technology |
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