Low-temperature and fast response H₂S gas sensor using semiconducting chitosan film

We report on novel, highly sensitive and low-temperature H₂S gas sensor based on chitosan (CS) film with engineered conductivity. The conductivity of the chitosan film is controlled by blending it with glycerol ionic liquid (IL) with different concentrations 1–9% volume/volume (v/v). The optimum conductivity of the film is depicted at 5% (v/v) concentration of glycerol. The fabricated films are flexible, transparent and hold semiconducting properties. The gas sensing performance was investigated for chitosan – 5% IL film. Results showed high sensitivity as well as selectivity for H₂S gas, outstanding reproducibility, and long-term stability. The lowest operating temperature of the sensor was 20 °C, with a minimum gas detection limit of 15 ppm. Moreover, the sensor exhibits a reasonably fast response, with a minimum average response time of 14.9 ± 3.7 s. This sensor with its low-power consumption, high flexibility, and easy fabrication technique, has the potential to be used for practical industrial applications.