Nanofibrous Polythiophene-SnO2 composite Films: A novel approach for Low-Temperature NO2 sensing

The SnO2-incorporated interconnected nanofibrous Polythiophene (Sn-INPTh) composite thin film was successfully synthesized using a simple chemical bath deposition method. The film was systematically studied for its NO2 gas sensing application. The chemical bonding, surface morphology, and optical properties were investigated using FT-IR, FE-SEM, EDAX, AFM, and UV-Visible spectroscopy. The effects of SnO2 incorporation on the physicochemical and NO2 sensing properties of the Sn-INPTh thin films were examined. The surface morphological study revealed the nanofibrous Polythiophene morphology, which remained intact after the incorporation of SnO2. The investigation of the chemical bonding nature clearly indicated the characteristic IR absorption bands of Polythiophene, along with the emergence of additional bands corresponding to the SnO2 nanoparticles. The Sn-INPTh thin film gas sensor demonstrated the highest selectivity for NO2 among the various oxidizing and reducing gases (NH3, SO2, H2S, NO2, CO, LPG) tested at a low working temperature of 40 +/- 2C. All of the Sn-INPTh composite thin films exhibited enhanced NO2 sensing performance, with the highest sensitivity of 81.5% and the shortest response time of 22.66 s observed for the optimized Sn-INPTh composite thin films.