Preparation and Optical Properties of PVDF-CaFe 2 O 4 Polymer Nanocomposite Films.

In this work, a synthesis technique for highly homogeneous PVDF-CaFe 2 O 4 polymer films direct from solution was developed. The structural characterizations were conducted using XRD, FTIR, and ESEM experimental techniques. The XRD characteristic peaks of CaFe 2 O 4 nanoparticles revealed a polycrystalline structure. The average crystallite size for CaFe 2 O 4 was calculated to be 17.0 nm. ESEM micrographs of PVDF nanocomposites containing 0.0, 0.25, 0.75, and 1.0 wt% of CaFe 2 O 4 showed smooth surface topography. The direct E dir and indirect E ind band gap energies for the PVDF-CaFe 2 O 4 nanocomposites were decreased with the additions of 0.0-1.0 wt% CaFe 2 O 4 . In addition, the refractive index ( n 0 ) increased from 3.38 to 10.36, and energy gaps (E g ) decreased from 5.50 to 4.95 eV. The nonlinear refractive index (n 2 ) for the PVDF-CaFe 2 O 4 nanocomposites was improved with the addition of CaFe 2 O 4 nanoparticles, exceeding those reported in the literature for PVC, PVA, and PMMA nanocomposites. Therefore, the PVDF-CaFe 2 O 4 nanocomposites are expected to take the lead in optoelectronic applications because of their unusual optical properties.