Optical absorption of Nd2O3-Doped polyvinylidene fluoride films

Optical absorbance measurement is a powerful tool for studying the optical properties of polymer materials. In this work, the optical properties of neodymium-doped polyvinylidene fluoride (PVDF/Nd) samples were studied at room temperature. The results show that addition of the Nd to the PVDF matrix enhances the optical transmittance up to 8.0%, and decreases it in the UV region for PVDF/Nd 1.0%. The absorption edge changes with an increase of neodymium oxide (Nd) content in the PVDF matrix. For pure PVDF, the extinction coefficient decreases from 200 to 230 nm and, after increasing, presents a peak at 347 nm, which is related to F-C bonds. For other compositions, Nd addition diminishes the intensity of the characteristic peak of PVDF. For all samples, the extinction coefficient value reduces quickly till 230 nm, and after that increases with an increase of wavelength. This effect might be related to optical absorption by spherulites and the Nd grain boundary. Skin depth decreases as a function of photon energy for all PVDF samples. The bandgap energy presents an oscillatory behavior that might be related to the defects formed by the addition of Nd. The Urbach energy and band tailing parameter follow the behavior of the bandgap energy. In summary, the results obtained in this work are in good agreement with those reported in the literature, and they are essential for the optical and photonic application of PVDF/Nd doped samples.