Influence of the counter ion on the properties of organic and inorganic acid doped polyaniline and their Schottky diodes

Abstract Pure and doped Polyaniline (PANI) was prepared by chemical oxidative polymerization of aniline. The FT-IR spectrum confirms the presence of dopants in PANI functional groups of SO 3 2− groups in PANI. SEM morphology reveals the various shapes and size of the PANI. UV–Vis spectra confirm the absorption peaks at 270 and 340 nm is due to the π–π ∗ transition of the benzenoid rings. The strong absorption peak around 603 nm showed extension of polymer chains. PL studies of PANI reveal the emission peaks around 325 nm and 510 nm of PANI. The conductivity measurements are carried out for the prepared PANI’s pellets. The heterojunction device structure In/PANI-DBSA/Al and In/PANI-HCl/Al was made to fabricate by thermal evaporation method. The current voltage ( I – V ) characteristics of these devices are weak rectifying behavior with the non-linear nature. The diode parameters such as ideality factor, barrier height and saturation current densities were calculated using the modified Shockley equation.