National Institute of Materials Science (NIMS) announced on May 6, 2011 that a chemical wiring method is developed for interconnection of each organic molecule by electrically conductive polymers. Details are published in Journal of the American Chemical Society, Article ASAP* by Researcher Yuji Okawa and his colleagues of NIMS International Center for Materials Nanoarchitectonics (MANA) with coauthors from organizations in Switzerland, Germany and United States.
Concerns of viable physical limitation of silicon based electronics have made single-molecule electronics to be a promising candidate for the future information systems. A challenge for its realization is connecting functional molecules to each other using conductive nanowires.
Researchers devised a method to create conductive nanowires at designated positions, and to ensure chemical bonding between the nanowires and functional molecules as follows. Functional molecules (phthalocyanine) are placed on a self-assembled monolayer of diacetylene compound. A probe tip of scanning tunneling microscope (STM) is positioned on the molecular row of the compound and stimulate the compound to form a conductive polydiacetylene nanowire by chain polymerization. Because of the high reactivity of the front edge of chain polymerization, the created polymer nanowire forms chemical bonding with an encountered molecular element, which will be named "chemical soldering".
First-principles theoretical calculations are used to investigate the structures and electronic properties of the connection. STM images demonstrated two conductive polymer nanowires connected to a single phthalocyanine molecule. A resonant tunneling diode is formed by this method as an example of single-molecule electronic devices.