Insitu growth of ternary metal sulphide based quantum dots to detect NO2 gas at extremely low levels with theoretical investigations

Utkarsh Kumar^1*, Yu-Hsuan Yang², Zu-Yin Deng¹, Ming-Way Lee¹, Wen-Min Huang¹, Chiu-Hsien Wu^1,2

¹Department of Physics, National Chung Hsing University, Taichung, Taiwan
²Institute of Nanoscience, National Chung Hsing University, Taichung, Taiwan

* Presenter:Utkarsh Kumar, email:Utkarsh218@gmail.com

In this paper, The advantage of ternary metal suphiles for the detection of NO2 at extremely low concentrations has been explored. Ultrafine TiO2/PbSnS based thin film has been fabricated by the Successive Ionic Layer Adsorption and Reaction (SILAR) method and employed as an effective NO2 sensor. The advanced material characterization technique such as HRTEM and XRD revealed that high-quality PbSnS nanoparticle with minimum crystallite size of 19.34 nm were obtained. The bandgap of the synthesizing material was estimated by using data of UV visible spectroscopy and reduces from 3.3 eV to 2.3 eV by adding ternary metal sulphide (PbSnS) in TiO2. The sensor also showed the best sensing performance with sensor response 0.24 at 100 ppb of NO2 at room temperature. The minimum response and recovery time was calculated and found to be 16.03 sec and 27 sec for NO2 at 23 ppb and the limit of detection (LOD) is extremely low i. e. 3.51 ppb for NO2 at room temperature. Density Function Theory has been used to explain the possible sensing mechanism for the sensing of NO2 using PbSnS nanomaterial. The contributions of Sn in TiO2/PbSnS for NO2 sensing, have also been analyzed experimentally as well as theoretically.

Keywords: Ternary metal sulphides, SILAR method, HRTEM, Gas sensor, DFT