1RIKEN, Japan; 2Japan Science and Technology Agency (JST), Precursory Research for Embryonic Science and Technology (PRESTO), Japan; 3The University of Tokyo, Japan
Reducing the thickness of thin-film electronic devices is one of a important strategy to add them wearable and stretchable systems features. When the total thickness of the electronic devices are reduced to several micrometers or less, the films can easily conform to rough surface such as human skins and these become highly stretchable in combination with rubber substrates. Here we report on recent progress of ultra-thin and printed organic integrated circuits and solar cells.
We successfully fabricated fully-printed organic TFTs and circuits on on 1-µm-thick parylene films. We combined several printing technologies such as inkjet and reverse-offset to make ultra-flexible and high performance organic circuits. To reduce the total thickness, we also fabricated free-standing electronic devices; the thin and free-standing dielectric layers in these devices are used as substrates and gate insulators at the same time.
The ultraflexible solar cells were fabricated on a glass substrate and a 1.0-μm-thick parylene foil. The combination of stable active layers which was developed by Takimiya and inverted architecture enables air-stable slar cells with a total thickness of 3 μm and they exhibited excellent power conversion efficiency.
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11:00am - 11:30am Invited
Roll-to-Roll Printing Electronic Devices
Singapore Institute of Manufacturing Technology, Agency for Science, Technology and Research (A*STAR), Singapore
Roll-to-Roll (R2R) printing is the process to create functional devices on a roll of flexible substrate. It is environmentally friendly and enables large-scale production of thin, flexible, wearable, lightweight functional devices with varying sizes and low cost. Nevertheless, the roll-to-roll printing is not mature enough to be applied to many areas since adjustments among materials, printing methods, registration, and inspection methods have not yet been established. SIMTech Large Area Processing Programme leverages on SIMTech’s interdisciplinary manufacturing technologies and competencies, aim to develop innovative R2R manufacturing technologies for nurturing and growing the emerging industry. This presentation will introduce our comprehensive key capabilities on material synthesis, coating, printing, embossing, photonic sintering, lamination, inspection, web handling and process monitoring for large area R2R processing. Some applications of R2R processing in transparent conductive film, optical film, light emitting, heater, sensor, etc. will also be highlighted.
11:30am - 12:00pm Invited
Soft Organic Electronics based on Graphene Electrodes
Pohang University of Science and Technology, South Korea
Graphene is considered as an excellent electrode material with a high transparency, good conductivity, and superior mechanical flexibility for use in next-generation flexible electronic devices, and at the same time as an attractive epitaxial template material for highly ordered organic crystal growth. The growth mode, morphology and the crystallographic structure of the organic semiconductors near the graphene-organic interface are strongly affected by various physicochemical characteristics of graphene, and they critically influence the performance of graphene-based organic electronic devices. In this talk I will discuss the challenges, opportunities, and our recent progresses in flexible organic electronics based on graphene electrodes. First, I will describe the growth behaviour of organic semiconductors on graphene electrodes, and their effects on the performances of organic transistors and photovoltaic cells. Then, I will introduce a new concept of using organic nanopatches to modify a CVD-grown graphene, which improved fracture strength without degrading any other supreme characteristics of graphene. With this mechanically strengthened graphene, robust and soft organic electronic devices were demonstrated.