Featured Research

from universities, journals, and other organizations

Formation of organic thin-film transistors through room-temperature printing

Date:
June 23, 2014
Source:
National Institute for Materials Science
Summary:
Researchers have established a process for forming organic thin-film transistors (TFTs), conducting the entire printing process at room temperature under ambient atmospheric conditions.

Ambient conductive metal nanoparticles and an organic transistor created in this research: (a) Schematic and a scanning electron micrograph of ambient conductive metal nanoparticles. With the use of conductive aromatic ligands, the nanoparticles exhibit conductivity matching that of metal by room-temperature drying. (b) Schematic of an organic TFT formed by a room-temperature printing process. Since all layers of the TFT can be formed without raising the temperature by even 1C, non-heat-resistant materials can also be used as substrates. It also exhibits extremely high mobility compared to conventional organic TFTs.
Credit: Copyright NIMS

Japanese researchers have established a process for forming organic thin-film transistors (TFTs), conducting the entire printing process at room temperature under ambient atmospheric conditions.

Printed electronics, the field in which electronic devices are produced by printing functional materials in ink form without the need for large and expensive manufacturing equipment, has been drawing attention in recent years as a new technology for low-cost, large-area fabrication of semiconductor devices. By using plastic and other flexible substrates, the technology is expected to open paths for the mass production of devices by roll-to-roll processing or for new applications such as wearable devices. However, conventional printed electronics require many high-temperature processes ranging from 100 to 200C. Because plastic substrates such as PET film generally have low heat resistance, there have been calls for the development of a low-temperature printing process that involves no high-temperature processes and that is applicable to a wide range of materials. However, such a process has not been realized to date.

In this research, the team established "room-temperature-printed electronics" by which electronics devices can be manufactured by conducting all of the printing processes at room temperature under ambient atmospheric conditions, without raising the temperature by even 1C. Conventional printed electronics have mainly required high-temperature processes in order to sinter metal nanoparticle ink to be used as electrodes. Since conventional metal nanoparticles have used insulating materials as ligands for dispersing the nanoparticles in the ink, the nanoparticles have needed to be sintered in order to obtain a conductive metal film.

In this research, the team succeeded in forming a metal film without post-coating sintering, by using conductive aromatic molecules as ligands of metal nanoparticles. The thin film obtained has achieved a resistivity of 9 10-6 Ω cm. In addition, by forming microscopic hydrophilic/hydrophobic patterns on the surface, the team patterned ambient conductive metal nanoparticles and organic semiconductors by a room-temperature process, and made organic thin-film transistors by forming all of the source and drain electrodes, organic semiconductors and gate electrodes by room-temperature printing. Organic TFTs formed on a plastic substrate and a paper substrate respectively indicated an average mobility of 7.9 and 2.5 cm2V-1 s-1. This value far exceeds the average mobility of amorphous silicon TFTs at 0.5 cm2 V-1s-1 and almost matches the mobility of mass-produced IGZO TFTs (up to 10 cm2 V-1 s-1).

When manufacturing displays, etc. by printed electronics, circuits need to be printed on flexible substrates at a positional accuracy greater than several microns. Flexible plastic and paper substrates, which are weak against heat, became deformed or distorted under the conventional processing temperatures, leading to compromised accuracy. By conducting all of the manufacturing processes at room temperature, it will be possible to completely control the heat deformation of substrates and to print micro circuits at high accuracy. Furthermore, the production processes at room temperature under ambient atmospheric conditions would, in principle, enable the production of electronic devices on the surface of materials that are extremely weak against environmental changes, such as biomaterials. This achievement is expected to lead to applications in diverse fields including health care and bioelectronics.

These research results will be published in the journal, Advanced Functional Materials, in the near future.


Story Source:

The above story is based on materials provided by National Institute for Materials Science. Note: Materials may be edited for content and length.


Cite This Page:

National Institute for Materials Science. "Formation of organic thin-film transistors through room-temperature printing." ScienceDaily. ScienceDaily, 23 June 2014. <www.sciencedaily.com/releases/2014/06/140623091641.htm>.
National Institute for Materials Science. (2014, June 23). Formation of organic thin-film transistors through room-temperature printing. ScienceDaily. Retrieved July 24, 2014 from www.sciencedaily.com/releases/2014/06/140623091641.htm
National Institute for Materials Science. "Formation of organic thin-film transistors through room-temperature printing." ScienceDaily. www.sciencedaily.com/releases/2014/06/140623091641.htm (accessed July 24, 2014).

Share This




More Matter & Energy News

Thursday, July 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

TSA Administrator on Politics and Flight Bans

TSA Administrator on Politics and Flight Bans

AP (July 24, 2014) TSA administrator, John Pistole's took part in the Aspen Security Forum 2014, where he answered questions on lifting of the ban on flights into Israel's Tel Aviv airport and whether politics played a role in lifting the ban. (July 24) Video provided by AP
Powered by NewsLook.com
Creative Makeovers for Ugly Cellphone Towers

Creative Makeovers for Ugly Cellphone Towers

AP (July 24, 2014) Mobile phone companies and communities across the country are going to new lengths to disguise those unsightly cellphone towers. From a church bell tower to a flagpole, even a pencil, some towers are trying to make a point. (July 24) Video provided by AP
Powered by NewsLook.com
Algonquin Power Goes Activist on Its Target Gas Natural

Algonquin Power Goes Activist on Its Target Gas Natural

TheStreet (July 23, 2014) When The Deal's Amanda Levin exclusively reported that Gas Natural had been talking to potential suitors, the Ohio company responded with a flat denial, claiming its board had not talked to anyone about a possible sale. Lo and behold, Canadian utility Algonquin Power and Utilities not only had approached the company, but it did it three times. Its last offer was for $13 per share as Gas Natural's was trading at a 60-day moving average of about $12.50 per share. Now Algonquin, which has a 4.9% stake in Gas Natural, has taken its case to shareholders, calling on them to back its proposals or, possibly, a change in the target's board. Video provided by TheStreet
Powered by NewsLook.com
Robot Parking Valet Creates Stress-Free Travel

Robot Parking Valet Creates Stress-Free Travel

AP (July 23, 2014) 'Ray' the robotic parking valet at Dusseldorf Airport in Germany lets travelers to avoid the hassle of finding a parking spot before heading to the check-in desk. (July 23) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins