Optical, electrical and morphological properties of (PANI/CSA-PEO)/(AgNPs-AgNO3) nanocomposite films

Nanocomposite films of hosted protonated polyaniline (PANI/CSA) in polyethylene oxide (PEO) and incorporated with silver nanoparticles and silver nitrate (AgNPs-AgNO3) were deposited on activated quartz substrates by spin coating technique. Deduced refractive index from UV–Vis spectrophotometry experiments falls in the range of 1.5–2.0 for undoped films, while for the nanocomposite films ranges between 1.7 and 2.1 due to the effect of AgNPs-AgNO3 incorporation. Scanning electron microscopy observations reveal that the typical PANI crystalline structure vanishes gradually with increasing AgNPs-AgNO3 content and the nanocomposite optical band-gap decreases with increasing concentration of AgNPs-AgNO3. An amorphous state is dominant in all nanocomposite films. The electrical conductivity increases with increasing dopant content due to polaron formation and increased concentration of Ag ions at concentrations below 60 wt.% of AgNPs-AgNO3 with respect to PANI/CSA. From fitting the data to a Sigmodial/Gomperz function for concentrations in the range of 100–360 wt.% it was found that the nanoparticles percolation was the dominant electrical conduction mechanism.