Prints Made on Flexible Substrates. Technique May Be Applicable to the Development of Wearable Devices.
A research team consisting of a group from National Institute for Materials Science (NIMS) International Center for Materials Nanoarchitectonics (MANA) and Colloidal Ink developed a printing technique for forming electronic circuits and thin-film transistors (TFTs) with line width and line spacing both being 1 μm. This study was supported by a Grant for Advanced Industrial Technology Development from NEDO.
Figure: Formation of microcircuit lines using a selective coating technique. (a) Schematic of selective coating technique. Only a hydrophilic region created through irradiation of parallel vacuum ultraviolet (PVUV) is coated with metal ink. (b) Electronic circuit with a line width of 5 μm formed through selective coating. (c) Electrode lines with different widths. Lines as narrow as 1 μm can be formed.
Copyright : NIMS
A research team consisting of MANA Independent Scientist Takeo Minari, MANA NIMS, and Colloidal Ink developed a printing technique for forming electronic circuits and thin-film transistors (TFTs) with line width and line spacing both being 1 μm.
This study was supported by a Grant for Advanced Industrial Technology Development, provided by the New Energy and Industrial Technology Development Organization (NEDO). Using this technique, the research team formed fully-printed organic TFTs with a channel length of 1 μm on flexible substrates, and confirmed that the TFTs operate at a practical level.
Printed electronics—printing techniques to fabricate electronic devices using functional materials dissolved in ink—is drawing much attention in recent years as a promising new method to create large-area semiconductor devices at low cost. Because these techniques enable the formation of electronic devices even on flexible substrates, they are expected to be applicable to new fields such as wearable devices.
In comparison, conventional printing technologies allow the formation of circuits and devices with line widths only as narrow as several dozen micrometers. Accordingly, they are not applicable to the creation of minute devices suitable for practical use. Thus, there were high expectations for developing new printing techniques capable of consistently fabricating circuits with line widths of several micrometers or less.
In this study, the research team developed a printing technique capable of forming metal circuits with line width being 1 μm on flexible substrates. Using this technique, they fabricated minute organic TFTs. The principle of this printing technique is as follows: First, form hydrophilic and hydrophobic micro-patterns on the substrate by irradiating it with parallel vacuum ultraviolet (PVUV) at a wavelength of 200 nm or less. Then, coat only the hydrophilic patterns with metal nanoparticle inks. The use of a PVUV light source (Ushio Inc.) enabled us to focus emitted light on much smaller targets than conventional light sources. Moreover, the use of DryCure-Au—metal nanoparticle ink that can form a conductive film at room temperature developed by Colloidal Ink—enabled us to form devices and circuits at room temperature during the entire process. As a result, we are able to fully prevent distortion of flexible substrates by heat, and form and laminate circuits within the accuracy of several microns. In addition, we precisely tuned the gate overlap lengths of the printed organic TFTs fabricated by this technique, which was previously impossible due to accuracy issues. As a result, a practical mobility level of 0.3 cm2 V-1 s-1 was accomplished for the organic TFTs with the channel length of 1 μm.
In future studies, we will aim to apply the technique in various fields such as large-area flexible displays and sensors. Since the process we developed is applicable to bio-related materials, the technique may also be useful in medical and bioelectronics fields.
This study was published in the online version of Advanced Materials on May 17, 2016.
Mikiko Tanifuji | Research SEA
Physics, photosynthesis and solar cells
01.12.2016 | University of California - Riverside
New process produces hydrogen at much lower temperature
01.12.2016 | Waseda University
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
02.12.2016 | Medical Engineering
02.12.2016 | Agricultural and Forestry Science
02.12.2016 | Physics and Astronomy