[Research] Prof. Cho, Hyung Koun’s research team suggests Memory-Type NO2 sensing system using anisotropic Semiconductor materials
- 신소재공학부
- Hit1379
- 2022-01-26
Prof. Cho, Hyung Koun’s research team suggests Memory-Type NO2 sensing system using anisotropic Semiconductor materials
[Figure 1] Prof. Cho, Ph.D candidate Young Been Kim (co-first author) and Sung Hyeon Jung
Prof. Hyung Koun Cho’s research team (co-first author Ph.D candidate Young Been Kim and Sung Hyeon Jung) from the Department of Advanced Materials Science and Engineering developed a progressive memory-type gas sensing system that has not only an alert system for highly concentrated NO2, but also memory-type responses to detect the cumulative occurrence of irregular exposures of low gas concentrations, thereby leading to a wide range of detection in a single sensing device.
Conventional toxic gas sensors’ primary function is to detect instantaneous gas emissions above fatal amounts. However, it is prevalent to be exposed to hazardous gas flow at concentrations lower than the lethal amount in practice, which is highly dangerous due to the cumulative effect. In order to produce signal according to irregular gas exposure, response and recovery processes should be occurring in the same environment whereas materials like typical n-type metal oxide semiconductors has difficulty acting so as it is operated through strong chemisorption.
[Figure 2]
Thus, the research team developed a novel system that enables both rapid alarm function at high concentration and memory-type gas sensing at low concentration based on designed antimony triselenide (Sb2Se3) nanoflakes.
[Figure 3]
Therefore, the research team developed a novel system that enables both rapid alarm function at high concentration and memory-type gas sensing at low concentration. Generally, low-dimensional material-based gas sensing can be operated at room temperature by Physisorption in the surface of van der Waals planes which means without any defect. On the other hand, the broken bonds of oxide-based sensing materials, i.e., dangling bonds, are driven by Chemisorption that reacts at high temperatures.
Due to its anisotropic two-dimensional crystalline structure, the Sb2Se3 nanoflake structure exhibits anisotropy in which the formed surface consists of van der Waals crystal planes and dangling bond planes, enabling NO2 detection at both room temperature and high temperature. In particular, unlike existing materials, this Sb2Se3 gas sensor requires a very low-voltage (1V) at room temperature. It can be operated continuously without any processing due to its recovery characteristic based on designed antimony triselenide (Sb2Se3) nanoflakes.
[Figure 4]
According to the crystalline planes of conductive materials with Sb2Se3 nanoflake structure, the research team utilized physisorption and chemisorption devices to create a memory-type sensing system equipped with room temperature operation and recovery functions.
[Figure 5]
Prof. Cho stated, "I find the development of Sb2Se3 gas sensors very meaningful as it enabled real-time tracking of irregular and continuous toxic gas emission that can lead to a fatal situation when accumulated."
This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (No. 2019R1A6A1A03033215). This work was also supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. 2021R1A2C3011870).
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