Optical and Chemical Investigations of PEO Thin Films Incorporated with Curcumin Nanoparticle: Effect of Film Thickness

Using the spin coating technique, polyethylene oxide (PEO)-Curcumin nanocomposite thin films have been deposited on a quartz substrate. The film thickness role on the optical properties was investigated. SEM investigated the morphology of the thin films and revealed that curcumin NPs have a spherical shape with an average size of less than 100 nm. FTIR bands observed at 1023 and 1120 cm–1 correspond to C–O stretching vibration. New bands observed for the thin films at 804, 1237, 1280, and 1340 cm–1 correspond to C–H, C–O, and O-H bending. The thin films’ optical properties with thickness 250, 500, and 750 nm were acquired from transmittance, reflectance, Tauc plot, extinction coefficient, and reflective index. The refractive index obtained from UV-Vis data falls between 1.5 and 2. Bandgap energy obtained for PEO thin film is 4.16 eV, while for both curcumin NPs and PEO-Curcumin nanocomposite thin films, the bandgap energy is 2.49 eV. Our results indicate that the optical absorption coefficient increases with decreasing film thickness. The obtained results are in good agreement with the existing reports.