Two Dimensional, Few-Layer MnPS3 for Selective NO2 Gas Sensing Under Ambient Conditions

In the present study, 2D few-layer MnPS3 is introduced as selective and reversible NO2 gas sensor in dry nitrogen (N2) under ambient conditions. Solvent exfoliation technique is utilized to exfoliate bulk MnPS3 into few-layers which are further assembled as thin films by vacuum filtration method. The film is subsequently transferred on to the sensing device and used for NO2 sensing. Exfoliated MnPS3 shows excellent sensitivity towards NO2 gas with low detection of limit of few tens of ppb at 25oC. Sensitivity of 9530 % is obtained at 35 ppm of NO2 with theoretical limit of detection (LOD) calculated to be ~9.5 ppb. The sensor is highly selective to NO2 gas (with respect to the interferents NO, NH3, H2 CO, CO2, C2H2, O2) and is fully reversible under ambient conditions. The time constant has been determined to be in range of 30-160 s for adsorption and desorption processes. Raman spectroscopy reveals that the mechanism of sensing is based on charge transfer interactions between the sensor and analyte. The ...