Thin layer of picene molecules attached to a silver surface maintain their structure and function, demonstrating potential for electronic applications
The emerging field of molecular electronics could take our definition of portable to the next level, enabling the construction of tiny circuits from molecular components. In these highly efficient devices, individual molecules would take on the roles currently played by comparatively-bulky wires, resistors and transistors.
A team of researchers from five Japanese and Taiwanese universities has identified a potential candidate for use in small-scale electronics: a molecule called picene. In a paper published September 16 in The Journal of Chemical Physics, from AIP Publishing, they characterize the structural and electronic properties of a thin layer of picene on a silver surface, demonstrating the molecule’s potential for electronic applications.
Picene’s sister molecule, pentacene, has been widely studied because of its high carrier mobility—its ability to quickly transmit electrons, a critical property for nanoscale electronics. But pentacene, made of five benzene molecules joined in a line, breaks down under normal environmental conditions.
Enter picene, in which these same five benzene rings are instead bonded together in a W shape. This simple structural change alters some of the molecule’s other properties: Picene retains pentacene’s high carrier mobility, but is more chemically stable and therefore better suited to practical applications.
To test picene’s properties when juxtaposed with a metal, as it would be in an electronic device, the researchers deposited a single layer of picene molecules onto a piece of silver. Then, they used scanning tunneling microscopy, an imaging technique that can visualize surfaces at the atomic level, to closely examine the interface between the picene and the silver.
Though previous studies had shown a strong interaction between pentacene and metal surfaces, “we found that the zigzag-shaped picene basically just sits on the silver,” said University of Tokyo researcher Yukio Hasegawa. Interactions between molecules can alter their shape and therefore their behavior, but picene’s weak connection to the silver surface left its properties intact.
“The weak interaction is advantageous for molecular [electronics] applications because the modification of the properties of molecular thin film by the presence of the [silver] is negligible and therefore [the] original properties of the molecule can be preserved very close to the interface,” said Hasegawa.
A successful circuit requires a strong connection between the electronic components—if a wire is frayed, electrons can’t flow. According to Hasegawa, picene’s weak interactions with the silver allow it to deposit directly on the surface without a stabilizing layer of molecules between, a quality he said is “essential for achieving high-quality contact with metal electrodes.”
Because picene displays its high carrier mobility when exposed to oxygen, the researchers hope to investigate its properties under varying levels of oxygen exposure in order to elucidate a molecular mechanism behind the behavior.
The article, "Scanning tunneling microscopy/spectroscopy of picene thin films formed on Ag(111)," is authored by Yasuo Yoshida, Hung-Hsiang Yang, Hsu-Sheng Huang, Shu-You Guan, Susumu Yanagisawa, Takuya Yokosuka, Minn-Tsong Lin, Wei-Bin Su, Chia-Seng Chang, Germar Hoffmann, and Yukio Hasegawa. It will be published in The Journal of Chemical Physics on September 16, 2014 (DOI: 10.1063/1.4894439). After that date, it can be accessed at: http://scitation.aip.org/content/aip/journal/jcp/141/11/10.1063/1.4894439
The authors of this paper are affiliated with the University of Tokyo, National Taiwan University, Academia Sinica, University of the Ryukyus, and National Tsing Hua University.
ABOUT THE JOURNAL
The Journal of Chemical Physics publishes concise and definitive reports of significant research in the methods and applications of chemical physics. See: http://jcp.aip.org
Jason Socrates Bardi, AIP
Jason Socrates Bardi | newswise
Epoxy compound gets a graphene bump
14.11.2018 | Rice University
Automated adhesive film placement and stringer integration for aircraft manufacture
14.11.2018 | Fraunhofer IFAM
Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.
Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...
Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.
In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...
On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.
When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure
Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...
Physicists at ETH Zurich demonstrate how errors that occur during the manipulation of quantum system can be monitored and corrected on the fly
The field of quantum computation has seen tremendous progress in recent years. Bit by bit, quantum devices start to challenge conventional computers, at least...
09.11.2018 | Event News
06.11.2018 | Event News
23.10.2018 | Event News
14.11.2018 | Materials Sciences
14.11.2018 | Health and Medicine
14.11.2018 | Life Sciences