A domestic research team has developed methods for silicon semiconductor parts for computers and smartphones to be replaced with flexible plastic parts. So far, flexible displays and batteries have been developed, but not semiconductors.
Bendable or flexible smartphones have been recognized as a core technology for the next-gen electronic industry. To make such smartphones, there has to be flexible plastic semiconductors in addition to flexible displays and batteries.
On November 5, a team of researchers, including Professor Kim Yoon-hee of the Gyeongsang National University Department of Chemistry and Professor Jung Dae-sung of Chung-Ang University, announced that they developed a high charge transfer rate plastic semiconductor material which can be used in many electronics components, from AMOLED to flexible displays.
To make a flexible display, a material which transfers charge well while having high machinability is needed. However, the original organic thin film transistor had the charge transfer rate (a value comparing the speed of a charged particle within the semiconductor to an outer electric field) of mostly less than 5, which is not suitable for use in AMOLED and other next-generation displays.
LCDs usually work with charge transfer rates of 0.5, but AMOLED requires the rate to be over 10. The research team developed a plastic semiconductor material with a charge transfer rate of 4.97 last January, followed by another development with a charge transfer rate of 12. Professor Kim announced that she noticed that adding hydrocarbon materials to plastic made of carbon high molecules causes internal molecules to line up, and the speed at which electrons move increased about 140%.
Professor Kim said, “This material will be available for use in not only displays, but also various fields such as solar batteries, sensors, RFID, and bio-recognition equipment,” and added, “The goal is to create an AMOLED smartphone made with AMOLED luminescent material developed by the research team, and a thin film transistor material with an organic solar battery made with materials developed by Gyeongsang National University.”
Kim explained, “Bendable plastic semiconductors will be commercialized prior to 2017,” and added, “Large domestic enterprises are negotiating how to commercialize the product.”
The result of this research was recently published in JACS, a scientific journal for chemistry.
Flexible Large Scale Integrated Circuits
Another domestic research team announced on November 7 that it succeeded in making a flexible Large Scale Integrated circuit (LSI), which is the core component in flexible displays, through testing a flexible LSI on a silicon board.
So far, research for developing flexible materials for flexible displays such as thin film transistors or other materials have been quite active, but research for developing flexible semiconductors were limited due to the difficulties in increasing the degree of integration.
Professor Lee Geon-jae of KAIST’s Department of New Materials Engineering and his team of researchers created an LSI connected to thousands of high performance nano-semiconductors for easily managing and saving large data. In fact, the semiconductor can be produced on top of the original silicon board instead of using new materials, allowing for its commercialization to be possible within just a few years.
Professor Lee said, “The newly-developed semiconductor is flexible, has a high degree of integration, and was created on human-friendly LCD polymer material, meaning that it can be used in shallow and curvy corners within the human body for bionic eye communications and others.”
The results of this research were published on October 25 in the online version of “ACS Nano,” the renowned journal in the nanotechnology field printed by the American Chemical Society.
New Carbon Materials
Also, Professor Kim Sang-wook of the KAIST Department of New Materials Engineering has succeeded in creating a new carbon material to be used for making semiconductors bent with chemical doping, long lasting batteries, and high efficiency photo catalysis. He improved the material’s quality by mixing various elements with the new materials such as grapheme or carbon nanotubes. His work has received a lot of attention recently. Professor Kim said, “It is now possible to process liquids which have been considered impossible in new carbon-related materials.”
Compared to grapheme and carbon nanotubes consisting only of carbon elements, the new material mixed with other elements allows better transfer of electricity and has better reactions, improving the low solvent dispersibility which has disrupted industrial use.
On November 5, Professor Kim announced he published a thesis regarding the “new carbon material development through chemical doping” in the 25th Anniversary special edition of the field-renowned journal “Advanced Materials.”