Characterization and linear / nonlinear optical aspects of polyaniline (PANI) films incorporated with Ethylenediamine for low-cost limiting optical technologies

Polymer composite combined film with Polyaniline (PANI) and Ethylenediamine (EDA) were successfully synthesized via the spin coating technique on a glass substrate followed by different thermal annealing degrees and times. Successful incorporation of EDA into the PANI polymer matrix and the effect of the annealing temperature have been demonstrated by XRD, FTIR, FESEM and TEM. Using UV–Vis optical spectroscopy, we determine the absorption coefficient, band edge, and Urbach energy. The effects of different annealing temperatures and times on linear/nonlinear optical characteristics were investigated. The band gap of EDA-doped PANI films is reduced with the different thermal annealing from 3.43 eV to 3.19 eV, while the Urbach tail of the 100 °C/4h film which is 0.492 eV was decreased to 0.469 eV for 150 °C/1h sample. However, the absorbance and optical conductivity were both increased. Besides, the optical limiting effect assesses their potential to mitigate intense light. It was found from the study that for green wavelength 100 °C/4h film decreases the input power by 16.5 % whereas the 150 °C/1h sample shows superior limiting behavior of 99.96 %. It has been found that thermal annealing of the EDA-doped PANI films enhances the synthetic composite's optical characteristics, making the 150 °C/1h sample of EDA-doped PANI films appropriate for utilization in both energy applications and optoelectronics. •Polymer composite combined film with Polyaniline (PANI) and Ethylenediamine (EDA) were successfully synthesized via the spin coating technique.•The red-shifted of the direct optical band gap is achieved by changing the thermal annealing.•The Urbach tail of the 100 °C/4h film which is 0.492 eV was decreased to 0.469 eV for the 150 °C/1h sample.•The Enhancement in the linear and nonlinear optical performance of the plain thermal annealing of the EDA-doped PANI films 150 °C/1h sample of EDA-doped PANI is characteristic and can be used in optoelectronics and optical devices.