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
Scientists from the MSU studied new liquid-crystalline photochrom
21.08.2017 | Lomonosov Moscow State University
Silk could improve sensitivity, flexibility of wearable body sensors
21.08.2017 | American Chemical Society
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
21.08.2017 | Medical Engineering
21.08.2017 | Materials Sciences
21.08.2017 | Life Sciences