Lim, Namsoo Lee, Jae-Sung Byun, Young Tae 2024-01-19T16:02:41Z 2024-01-19T16:02:41Z 2021-09-02 2020-12 2079-4991 https://pubs.kist.re.kr/handle/201004/117786 In this study, we demonstrated a highly selective chemiresistive-type NO2 gas sensor using facilely prepared carbon dot (CD)-decorated single-walled carbon nanotubes (SWCNTs). The CD-decorated SWCNT suspension was characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD), and UV-visible spectroscopy, and then spread onto an SiO2/Si substrate by a simple and cost-effective spray-printing method. Interestingly, the resistance of our sensor increased upon exposure to NO2 gas, which was contrary to findings previously reported for SWCNT-based NO2 gas sensors. This is because SWCNTs are strongly doped by the electron-rich CDs to change the polarity from p-type to n-type. In addition, the CDs to SWCNTs ratio in the active suspension was critical in determining the response values of gas sensors; here, the 2:1 device showed the highest value of 42.0% in a sensing test using 4.5 ppm NO2 gas. Furthermore, the sensor selectively responded to NO2 gas (response similar to 15%), and to other gases very faintly (NO, response similar to 1%) or not at all (CO, C6H6, and C7H8). We propose a reasonable mechanism of the CD-decorated SWCNT-based sensor for NO2 sensing, and expect that our results can be combined with those of other researches to improve various device performances, as well as for NO2 sensor applications. English MDPI GRAPHENE QUANTUM DOTS GAS SENSORS SENSING MECHANISM CITRIC-ACID NANOPARTICLES NETWORKS FILMS Negatively-Doped Single-Walled Carbon Nanotubes Decorated with Carbon Dots for Highly Selective NO2 Detection Article 10.3390/nano10122509 1 NANOMATERIALS, v.10, no.12 NANOMATERIALS 10 12 scie scopus 000602496900001 2-s2.0-85097950005 Chemistry, Multidisciplinary Nanoscience & Nanotechnology Materials Science, Multidisciplinary Physics, Applied Chemistry Science & Technology - Other Topics Materials Science Physics Article GRAPHENE QUANTUM DOTS GAS SENSORS SENSING MECHANISM CITRIC-ACID NANOPARTICLES NETWORKS FILMS Carbon dots single-walled carbon nanotubes nitrogen dioxide gas sensor