A research group led by Assistant Professor Kou Li at Chuo University, Japan, has achieved a significant breakthrough in non-destructive testing (NDT) with the development of chemically enriched photo-thermoelectric (PTE) imagers utilizing semiconducting carbon nanotube (CNT) films. This innovation, detailed in a recent publication in Communications Materials, promises to enable more efficient remote and on-site inspections by delivering enhanced response intensity and substantial noise reduction.
CNT film-based PTE imagers are crucial for advanced multimodal NDT, yet conventional designs have struggled to achieve the high response intensity necessary for practical wireless data logging. Existing methods, while focusing on minimizing noise, often result in response intensities of only a few millivolts. This limitation creates a mismatch for coupling with compact wireless circuits, which are indispensable for on-site inspection applications requiring higher intensity responses, typically in the order of a few millivolts or more.
The Chuo University team's solution involves developing chemically enriched PTE imagers composed of semiconducting CNT (semi-CNT) films. While semi-CNTs inherently offer stronger thermoelectric responses than the semi-metal mixtures found in conventional PTE devices, the new imager takes a critical step further. It employs p-/n-type chemical carrier doping to effectively mitigate the significant bottlenecking noise that has previously hindered performance. This doping process dramatically enhances the material properties for PTE conversion with semi-CNTs, achieving an improvement of up to 4,060 times.
The newly developed imager maintains performance characteristics similar to conventional CNT film devices, including ultrabroadband sensitive photo-detection with a remarkable minimum noise sensitivity of 5 pWHz−1/2, even under repeatedly deformable configurations. Crucially, it advantageously exhibits a response signal intensity exceeding a few to tens of millivolts. These combined features are pivotal, enabling remote, on-site non-destructive PTE imaging inspection with palm-sized wireless circuits, thereby opening new avenues for portable and highly effective NDT applications across various industries.
Reference: https://www.eurekalert.org/news-releases/1091180
