“Printing” photo-thermoelectric imagers on soft sheet

Non-destructive inspections play indispensable roles in rapidly growing industrial mass-production and social distribution in the borderless Internet of Things age. Inspired by traditional art and clothing’s processing method “wood-block print,” the research group of Department of Electrical, Electronic, and Communication Engineering, Faculty of Science and Engineering, Chuo University, led by the Assistant Professor Kou Li, Professor Yukio Kawano, and the graduate student Yuto Matsuzaki fabricated the photo-thermoelectric imagers applying screen coating method. The fabrication method focuses on screen coating on large area of soft sheet and the material inks, enhancing the durability. The study expects that combining various ink materials in the phase of screen coating extremely simplify integrated mount of multi-functional device substrate, which contributes to the manufacturing of highly durable image sensor sheets for non-destructive inspection use.

The research group have succeeded in developing high-yield fabrication process of multi-functional Photo-Thermoelectric Imagers on Soft Sheet by applying screen coating technology (Figure1/a). The research group is developing the sensor as an element technology applied to multi-functional non-destructive inspection, which was originally focused and applied to the non-destructive inspection (term 3) technology such as “material identification (term 1)”, “structural restoration (term 2)” that visualize interior materials assemblage or shape and layer construction, without destroying three-dimensional structures (ex: in-vehicle components, medical tools, infrastructure equipment, animals, plants) consisting from various materials and structures. Conventional device fabrication process was the filtration & transfer method (term 4) which transfer and interface each materials such as sensor channel, doping, electrode wiring only to the necessary part. However, the process was hindered by occasional disconnections between materials resulting in malfunction. The lack of material’s mechanical robustness remained to be the issue.

In this study, the research team have improved the fabrication efficiency and the durability, thanks to the invented fabrication process of screen coating technology that forms all liquidized ink materials in high adhesive manner, ended up to control the device disconnections and malfunctions. This outcome will contribute to the large scale aggregation and customized fabrication etc. required in social implementation of photo-thermoelectric imager sensor sheet, and we expect further development of application in the future.

The study report is released online on Advanced Materials Interface, as of Sept. 22, 2023.

<terms>
1. material identification
Technology which individually identifies material combinations of composite inspection object.

2. structural restoration
Technology which identifies an internal composition of inspection object such as hollow, multi-layered, curved etc.

3. non-destructive inspection
Inspection technology that detect or visualize the occurrence of defection, transformation, and deterioration inside inspection object without “destroying substances.” 

4. The filtration & transfer method
The adhesive transfer from a membrane substrate to a tape. Beside adhesive transfer, the method using low gravity (van der Waals force) which acts between molecules is also reported.