Improved N,N-Dimethylformamide vapor sensing using WSe[formula omitted]/MWCNTs composite at room-temperature

Abstract

The detection of air contaminating volatile organic compounds (VOCs) like N,N-Dimethylformamide (DMF) under room temperature and highly humid conditions is a tough task to accomplish. Herein, we demonstrate a high-performance chemiresistive gas sensor which was fabricated using composite of layered nanosheets of WSe2 and multiwalled carbon nanotubes prepared using facile single-step hydrothermal method. Structural analysis via various material characterization techniques not only established the composite formation but also indicated the presence of stacking faults and enhanced specific-surface area for the composite, which collectively determine the improved sensing performance of the device. Composite has shown nearly three times enhancement (4.3%) in sensing response compared with WSe2 (1.5%) alone. Sensor has displayed clear noise free signal for DMF detection down to 2 parts per million (ppm) with faster response (1.37 min), recovery rates (0.82 min) and theoretical limit of detection around ≈ 440 parts per billion (ppb). Sensor has shown a reasonable selective behavior towards DMF as compared with other eleven analytes. This was further corroborated via principal component analysis method. Reproducibility of device fabrication and response transients were successfully performed at different humidity levels. Stable and reproducible sensing characteristics over a wider range of relative humidity justify the potential use of WSe2 based composites for various sensing applications.