The 296th MANA Seminar
Dr. Yun Li & Prof. Amar Prasad Yadav
| Date | November 9, Friday |
| Time | 15:30-17:00 |
| Place | Auditorium, 1F, WPI - MANA Bldg., NAMIKI Site, NIMS |
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15:30-16:15
Patterned Organic Crystals from a Direct Spin-coating Process for Transistor Arrays
Organic electronics has been the subject of intensive interest because of their potential in electronic devices. Major factors that determine the development of organic electronics in future are further increase in device performance, reduction of manufacturing costs, and extension of applications. Here, we present a fabrication technique for patterned organic crystals transistor arrays, which meet all the above-mentioned requirements. A mixture solution of organic semiconducting small molecule and insulating polymer was spin-coated onto a substrate with patterned surface wettability. Organic crystals, which are regarded as the ideal materials for high device performance, were formed within the patterned regions without any post treatment. The grain sizes were observed as large as hundreds of micrometers. High device performance and uniformity were obtained from the fabricated transistor arrays, exhibiting the field-effect mobility more than 1 cm2/Vs and the on/off ratio of 108. Besides, patterning the active materials is desirable for turning organic crystals into a viable semiconductor technology. This solution-assisted process is simple and efficient, and would highly reduce the manufacturing costs. Furthermore, it was found that the proposed method could create a very smooth semiconductor/dielectric interface. Thus, we were successful in presenting the first demonstration of patterned organic crystals transistor arrays on paper. Despite large surface roughness of paper substrates, the devices exhibited excellent electrical performance, possessing the highest values of both carrier mobility and on/off ratio for OFETs on paper so far. It promises that the proposed method also benefits for extending the applications of organic electronics.
Speaker
Dr. Yun Li, School of Electronic Science & Engineering, Nanjing University, China
Chair
Dr. Kazuhito Tsukagoshi, MANA PI, MANA, NIMS
16:15-17:00
Effect of Ce(III) on Electroploymerization of Aniline onto Active Metal Substrate
In this `polymer age' of today, tremendous advancement has been made in developing various polymeric materials which are fast replacing the conventional materials such as metals and alloys in number of applications, thus bringing about cost-effectiveness, reduction in size and weight, new designs and in fact entirely new concepts in materials science. Conductive polymers offer interesting mechanical and electrical properties which allowed their use in a large field of applications such as energy storage, electrocatalysis, photoelectrochemistry, electroanalysis, sensors, electrochromic displays, microsystem technologies, electronic devices, microwave screening and corrosion protection etc. In the area of corrosion protection of active metals, conductive polymers have been found to be promising candidate in replacing the conventional chromate conversation coating which is banned now due to environmental concern. Preparation, characterization and application of electrochemically active conducting polymeric systems are still in the foreground of research activity in electrochemistry. Electrochemical techniques are suitable for controlled synthesis of conductive polymer, fine tuning of a well-defined oxidation state and its characterization. It is found that the structure and electronic properties of conductive polymers are strongly related to synthesis conditions. In this talk, effect of Ce(III) on the electropolymerization of aniline onto mild steel from aqueous oxalic acid solution will be discussed. Electroploymerization of aniline on active metal is not easy since metal get oxidized before the oxidation of monomer is reached. To structure a good film therefore, it is necessary to optimize the electrochemical condition. Chronoamperometry and cyclic voltammetry methods for the formation of polyaniline film (PANI) in the presence of Ce(III) ion will be discussed in this talk. The effect of Ce (III) ion on the structure of PANi film and possible applications will be discussed.
Speaker
Prof. Amar Prasad Yadav, Central Department of Chemistry Tribhuvan University, Kathmandu, Nepal
Chair
Dr. Jin Kawakita, MANA Scientist, MANA, NIMS