Reviewed by Lexie CornerMay 14 2025
A research team at Chuo University in Japan, led by Assistant Professor Kou Li, has developed a fully printable device fabrication approach aimed at addressing key technical challenges in producing multifunctional image sensor sheets for non-destructive inspection applications.
Concept / By printing sensors on various substrate materials, unique functions specific to each can be realized. Image Credit: Chuo University
While photo-thermoelectric (PTE) sensors offer ultrabroadband monitoring capabilities that are beneficial for non-destructive testing, traditional fabrication methods hinder high-yield integration due to spatial misalignment caused by separately fabricating each component.
The researchers demonstrated a mechanically alignable, fully dispenser-printable integration method for carbon nanotube (CNT)-based functional PTE sensor devices using solution-processable ink materials. Their technique begins with the precise printing of CNT channels—critical for PTE conversion—using high-concentration inks. The remaining components, including dopants and conductive pastes, are then added to complete the devices with high yield.
The study further shows that these high-concentration CNT inks enable mechanical channel printing and produce sensitive PTE sensors. The integrated devices function reliably on various functional substrates, allowing non-destructive monitoring tailored to specific structural features and environmental conditions such as temperature and humidity.
The study presents the following key advancements:
i) Preparation of all component materials of the functional PTE sensor sheets (including CNT light-absorbing channels, wiring electrodes, and carrier dopants) in liquid ink forms suitable for consecutive, fully solution-based processing on a single platform.
ii) Development of high-yield formation and integration processes for each component of the CNT film PTE sensor sheet. This eliminates the typical bottleneck of manual spatial alignment by using a single air-jet mechanical dispense printer to handle all device inks consistently.
iii) Demonstration that employing highly concentrated CNT inks, crucial for high-yield printing, effectively provides ultrabroadband photodetection capabilities comparable in sensitivity to existing narrowband devices, fulfilling the core material function in the PTE sensor sheet.
iv) Enhancement of the versatility of CNT film PTE sensor sheets as widely applicable inspection tools through diverse modular configurations (e.g., high-resolution imagers, wearable gloves, and transparent patch scanners). This is achieved via universal and high-yield all-dispenser-printable device fabrication, regardless of the substrate material.
Journal Reference:
Yamamoto, M., et al. (2025). Mechanically alignable and all-dispenser-printable device design platform for carbon nanotube-based soft-deformable photo-thermoelectric broadband imager sheets. npj Flexible Electronics. doi.org/10.1038/s41528-025-00419-2