Manufacturing technologies
Next generation healthcare, Agriculture IoT, Construction techResearch on creation of ultra-flexible
and highly transparent electronics
Department of Advanced Materials and Implementations, SANKEN (The Institute of Scientific and Industrial Research)
Associate Professor Teppei Araki
https://researchmap.jp/teppei_araki?lang=en

Abstract
We create multifunctional advanced materials by designing nano- andmicro-materials to construct novel electronic devices and to explore themechanisms of device characteristics. In addition, flexible electronics thatis integrated and packaged with the novel electronic devices is studied andapplied to solve issues in social communities. We are actively promotinginterdisciplinary research to create completely new values and electronics
systems, and to unravel the mechanisms that cause the transformation insocial system (health care for people/agriculture/infrastructure fields, etc.).
We are challenging to develop a wide range of applications from electronics
packaging of advanced materials to their implementation in society.

on the construction of thin-film, flexible, and transparent sheet-type sensors by integrating stretchable conductor materials, mainly organic andinorganic nano-materials, into organic devices. By developing electronicdevices that are as flexible as human skin and as transparent as water,
and that can be clearly observed even by non-experts, a fundamental
technology is being created for next-generation personal sensors that canseamlessly fit into our daily lives.

Manufacturing technologies▍ Background & Results
In recent years, stress-related diseases are estimated to affect morethan 4 million people in Japan, and wearable sensor technology to quantify
stress in daily life is in high demand. To realize imperceptible sensors, thisresearch field has developed thin-film, stretchable, transparent conductorsthat can wirelessly measure low-noise potential signals (approximately 0.1uV) equivalent to those of medical materials by utilizing biosafety conductormaterials. One of the key materials, a bio-dry electrode, is composed of anelastomer and a conductive polymer, which form a nano- to micrometer-sizedphase-separated structure in the material. Furthermore, by using an inorganic (metallic) material consisting of Ag/Au core-shell nanowires, which areinvisible to the naked eye, as the wiring material, we have constructed highlyconductive and transparent stretchable wiring. The transparent sensor sheet,
which is composed of a bio-dry electrode and a stretchable wiring layer, exhibits high electrical conductivity, making it an important probe for low-noise
potential measurement equivalent to that of medical materials (Fig. 1). We
have also developed a new technology for low-damage multilayer patterningof metallic and organic nanomaterials described above, and developed “thinfilm, flexible, and transparent electrochemical transistors” (Fig. 2).
On the other hand, we have succeeded in on-site measurement of
aqueous solution concentration using only a simple process of attachinga sensor sheet (Fig. 3). By focusing on the broadband infrared radiation emitted from the liquid solvent itself and its local absorption by thesubstance, a sample-less and label-free liquid quality measurement hasbecome possible. This liquid quality measurement uses a highly sensitive,broadband, and stretchable thin-film optical sensor sheet newly developedby our research group. The sheet can be attached to soft materials suchas plants, vinyl chloride pipes, serpentine pipes, and rubber tubes, andcan stably follow the expansion, contraction, bending, and other deformations of the pipes caused by liquid flow. The results of this research, which
demonstrate a fundamental technology that contributes to ubiquitous water quality testing, are expected to contribute to the construction of safety
nets for infrastructure and agriculture in the future.

Fig. 1 (Copyright permission from Adv. Mater. Technol.)Fig. 2 (Copyright permission from Adv. Sci.)▍ Significance of the research and Future perspective
Through our research and development of multifunctional and high-performance printed circuit boards required for flexible hybrid electronics(FHE), we carry out research on their application to healthcare sensor systems for the human/agriculture/infrastructure fields. In particular, we focus

Fig. 3 (Copyright permission from Sci. Adv.)P a t e n t Japanese Patent No. 6889941, 6865427, 6832535
Araki, Teppei; Li, Kou; Suzuki, Daichi et al. Broadband photodetectors and imagers in stretchable electronics packaging toward construction of cyberphysical systems, Advanced Materials 2023, 2304048. doi: 10.1002/adma.202304048
Takemoto, Ashuya; Araki, Teppei; Nishimura, Kazuya et al. Fully transparent, ultrathin flexible organic electrochemical transistors with additive integration
for bioelectronic applications, Advanced Science 2023, 10 (2), 2204746. doi: 10.1002/advs.202204746
Tr e a t i s e
Araki, Teppei; Yoshimoto, Shusuke; Uemura, Takafumi et al. Skin-like transparent sensor sheet for remote healthcare using electroencephalography andphotoplethysmography, Advanced Materials Technologies 2022, 7 (11), 2200362. doi: 10.1002/admt.202200362
Araki, Teppei; Uemura, Takafumi; Yoshimoto, Shusuke et al. Wireless monitoring using a stretchable and transparent sensor sheet containing metal
nanowires, Advanced Materials 2020, 32(15), 1902684. doi: 10.1002/adma.201902684
UR
L https://www.sanken.osaka-u.ac.jp/en/organization/srp/srp_02_05/
K e y w o r d nano & micro materials, flexible electronics packaging, sensors & systems