Synthesis and study of polyaniline/MWCNT composite for optoelectronic application

In this study, the effect of multi-walled carbon nanotubes (MWCNTs) addition on optical bandgap of polyaniline (PANI) was reported. Pure PANI and 5 mg MWCNTs/PANI, 10 mg MWCNTs/PANI and 15 mg MWCNTs/PANI composite samples were synthesized by in-situ polymerization process. Synthesized composite sample and pure PANI sample were characterized by X-ray diffraction, scanning electron microscopy, Fourier transform-infrared and UV–visible spectroscopy. Optical bandgap, molar absorptivity coefficient are estimated for pristine MWCNTs sample, pure PANI sample and composite samples using UV–visible spectroscopy data and Tauc plot. It is observed that optical bandgap of PANI decreases on increasing the concentration of MWCNTs, while keeping the concentration of PANI constant. Lowest bandgap of 3.55 eV is obtained for 15 mg MWCNTs/PANI composite sample. Strong interaction between π-bonded surface of MWCNTs and quinoid rings of PANI is found, as indicated by the obtained results of FTIR and UV–visible spectroscopy. The information on the optical bandgap of the composite samples is of great importance for the development of optical antenna and other optoelectronic devices.