Microstructure Study And Linear/Nonlinear Optical Properties of Bi-Embedded PVP/ PVA Films For Optoelectronic And Optical CUT-OFF Applications

Abstract

Hybrid polymer films of polyvinyl pyrrolidone (PVP)/ polyvinyl alcohol (PVA) embedded with gradient levels of Bi-powder were prepared using a conventional solution casting process. X-ray diffraction (XRD), Fourier transform infrared spectroscopic (FT-IR), and Scanning electron microscope (SEM) techniques have been used to examine the micro/molecular structural and morphological of the synthesized flexible films. The XRD peak intensity and FTIR spectra of the PVA gradually decline as Bi-metal is introduced. In addition, filler changes the microstructure surface of the pure film. The modification in the microstructure leads to an enhancement in the optical characteristic of the blend films. The indirect allowed transition energy was calculated via Tauc's and ASF models. The decrease in the hybrid film’s bandgap (\({E}_{gi}^{opt}\)) returns to the localized states in the forbidden region, as illustrated by the Urbach energy (Eu) values. The optical absorption parameters, including absorption coefficient (α) and edge (Ee), have also been evaluated. The relation between the transition energy and the refractive index (n) was studied. The rise of Bi-metal concentrations leads to an improvement in the nonlinear (χ(3)) susceptibility and (n2) refractive parameters. The optical limiting characteristics (OLC) revealed that the higher concentration dopant films reduce the light transmission intensity. The results suggest that hybrid films are promising materials in a wide range of applications, especially optical devices, and optoelectronics.