Abstract:
Background: Optical sensing with CNT sensor devices utilizes the photo-thermoelectric (PTE) effect as a measurement principle (Fig. 1a). A typical example of their application is non-destructive material identification [1]. To improve the sensing capability, it is necessary to enhance the PTE response, which is the principle underlying the sensing process. Designing the Seebeck coefficient difference between p-type and n-type CNTs to be significant leads to an increase in the response intensity of the PTE response. In this case, the challenge is to fabricate an n-type CNT that can provide a stable PTE response. In this study, in addition to the conventional dispensing technique for p-type CNT, this work has established a dispensing printing technique for n-type carbon nanotubes to create a PTE carbon nanotube camera device (Fig. 1b). This work demonstrates the photo absorption characteristics of the n-type CNT created in this experiment over broadband and evaluates the fabricated 2D CNT camera device.
Methods: This work creates n-type CNT as a material ink using dispense printing and evaluates its photo absorbance character with a broadband IR laser.
Results: In this work, stable dispensing of n-type CNT by dispense printing was successfully achieved. To confirm the absorbance properties of the deposited n-type CNT, the PTE response was measured by near-infrared laser (NIR) and far infrared region laser (FIR) for different lengths of CNTs (Fig. 1 c– d). In both regions, peaks are reached for each different length of CNTs. The responses show the opposite polarity to the p-type response, indicating that the response is ideal. Since these n-type CNTs do not lose their photo absorption properties, this work succeeded in designing a PTE camera sheet (Fig. 1b), which can be used for ultra-broadband imaging based on the principle of PTE response. To evaluate the performance of the CNTs thin-film camera, this work demonstrates a video measurement using an object. The motion of the letter “P” of the subject can be observed by using the CNT camera sheet (Fig. 1e). These results show that the CNT camera can be used not only for still image measurement but also for video measurement.
Conclusions: In this work, the optical absorption properties of n-type CNTs by dispense printing can detect photos in an ultra-broadband range. In addition to that, this work can confirm that the film deposition in dispense printing does not lose its photo-absorbing properties depending on its length. This has led to the successful fabrication of a CNT camera with high PTE response in combination with p-type CNTs. The camera's performance was confirmed through video measurement.
Biography:
Mr. Yukito Kon graduated from the Department of Electrical, Electronic, and Communication Engineering, Faculty of Science and Engineering, Chuo University. He contributed to three submitted papers as a co-author. Two of them were applauded as the back cover and frontispiece of the journal. He is also enthusiastic about presenting at international conferences. He is planning to participate in Carbon 2025 in France and IR-MMW in Finland.
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