Study the Structural and Optical Properties (Energy Gap) of Polythiophene/MWCNT/SnO2 Nanocomposite as an NO2 Gas Sensor

Abstract

The polythiophene (PTh) is of great interest in various applications due to its unique electrical, mechanical and structural. In this work, PTh was synthesized using the oxidation method by employing ferric chloride (FeCl₃) as an oxidizing agent, Then the nanocomposite polythiophene: Multi walled carbon nanotubes: Tin (IV) oxide (PTh/MWCNT/SnO₂) was prepared by adding constant weight ratio of MWCNT(0.7g) and different weight ratios of  SnO₂ (0.1, and 0.5g) using the oxidation method. The FE-SEM images of the pure PTh and the nanocomposite showed an apparent change in the morphological composition of the surface. The X-ray diffraction (XRD) pattern of PTh/ MWCNT/SnO₂ nanocomposites show the appearance of clear peaks for SnO₂, while there are broad peaks for MWCNT. As for the polymer, its behavior is random. The morphology of these nanocomposites shows that the nanotubes were not well aligned and were randomly entangled. The Fourier transformer infrared (FT-IR) spectra of the pure and nanocomposite samples prepared by chemical method in the range of 450-4000 cm^-1 wave number are recognized the chemical pledges (bonds) as well as functional groups in the compound. The band gap energy decreased from 3.53 into 2.78 and 2.97 when SnO₂ was added. The sensitivity of the two nanocomposites shows a good enhancement 14.6% and 62% at temperature 150^oC as gas sensor.