Enhanced nonlinear absorption and optical limiting of transparent, electrospun graphite filled polymer composite nanofibers in near IR region


PEPE Y., AKKOYUN Ş. , KARATAY A., Akhuseyin Yildiz E., ATEŞ A. , ÜNVER H., ...More

Journal of Materials Science, 2022 (Journal Indexed in SCI Expanded) identifier

  • Publication Type: Article / Article
  • Publication Date: 2022
  • Doi Number: 10.1007/s10853-021-06603-9
  • Title of Journal : Journal of Materials Science

Abstract

© 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.PVP (Polyvinylpyrrolidone) and PVP/GR composite nanofibers containing 1.0, 1.5 and 2.0 wt% of graphite (GR) filler were produced by electrospinning. The nanofibrous structure of electrospun mats allows high light-matter interactions, which greatly affects the nonlinear optical character of the materials. SEM measurements showed that the PVP/GR nanofibers are smooth, transparent and of cylindrical morphology in the 161–218 nm diameter range with a high homogeneity. The energy band gap increased from 1.87 to 2.02 eV and then decreased to 1.83 eV with increasing GR filler concentration in PVP while the Urbach energy decreased indicating the existence of localized defect states. To derive the transmission in open aperture Z-scan data at 1064 and 1200 nm, a theoretical model incorporating one-photon, two-photon and free carrier absorptions and their saturations were considered. The nonlinear absorption coefficient (βeff) increased from 3.31 × −5 to 1.01 × −4 m\W with increasing GR filler concentration in PVP although increasing GR filler content leads to decrease the number of defect states. The enhanced nonlinear absorption and optical limiting behavior with increasing GR filler content in PVP nanofibers are attributed to the increasing metallic nature, which enhances the FCA contribution. Femtosecond transient absorption spectroscopy measurements indicated that the charge transfer increases in GR-filled nanofibers. Our findings showed that GR-filled nanofibers feature highly desired properties in optical limiting applications such as high linear transmittance (> 80%), high nonlinear absorption and low optical limiting threshold. Therefore, these materials are good optical limiter candidates in the near IR wavelength region. Graphical abstract: [Figure not available: see fulltext.]