Facile chemical bath deposition method for interconnected nanofibrous polythiophene thin films and their use for highly efficient room temperature NO2 sensor application

- Polythiophene thin film gas sensor was prepared successfully by chemical bath deposition technique at room temperature.
- The present study highlights the crucial role of monomer concentration to optimize highly porous interconnected polythiophene network with precise control of pore size.
- Interconnected nanofibrous polythiophene thin film sensor demonstrated its ability to detect very low NO2 concentration of 1 ppm with precise sensitivity.

Interconnected nanofibrous polythiophene (INPTh) film was deposited on the glass substrate through a simple chemical bath deposition method. The influence of monomer concentration on INPTh film properties as well as on NO2 sensing properties of the film was studied. The morphological and structural studies were carried out using FTIR spectroscopy, FE-SEM microscope, and AFM analysis. The FTIR spectra confirmed the formation of PTH structure. The interconnected nanofibrous surface morphology was observed in FE-SEM images. The roughness of the film and thickness (225 nm-442 nm) was found to increase with monomer concentration up to 0.5 M, after that, both decreased at 0.6 M monomer concentration. The highest selectivity of PTh thin film towards NO2 was observed than the other gases like H2S, SO2, NH3, CO and LPG. The influence of film morphology and thickness on gas sensing properties was observed, which was varied with monomer concentration. The film deposited at 0.5 M monomer concentration showed the highest NO2 gas response of 47.58% at room temperature. Present results revealed that monomer concentration was also one of the deposition parameters for tuning the morphological as well as gas sensing properties of the chemical bath deposited PTh film.