CSA-doped PANI semiconductor nanofilms: synthesis and characterization

Abstract

Camphorsulfonic acid doped polyaniline (PANI-CSA) prepared by chemical oxidative polymerization is dip coated on glass plates with three different PANI:CSA weight ratios (1:0.5, 1:1 and 1:2). Films of thickness being <100 nm are termed as nanofilms. Fourier transform infrared spectroscopy indicated the presence of dopant and increase in degree of polymerization with increase in dopant level. X-ray diffraction studies revealed the amorphous nature of the films. Scanning electron microscopy showed very smooth morphology without any crack or pores. Hall-effect analysis showed that the increase in CSA weight ratio appreciably increases the conductivity of PANI-CSA films due to increase in carrier concentration and it also represents the semiconductivity (P-type) nature in all the films. UV–visible absorption spectra and photoluminescence spectra revealed that high intense absorption and emission peaks occur for the PANI-CSA film with PANI:CSA weight ratio (1:2). This appreciable increase is due to increase in charge carriers. Photoluminescence study of PANI-CSA films excited using 300 nm shows high intense peaks at 361 and 494 nm and a weak peak at 410 nm which confirmed the semiconducting nature of the film.