Terahertz, Infrared, and UV-Vis Spectroscopy Study on Silver Polyaniline Core Shell Nanocomposites; Optical and Electronic Properties

Abouelsayed, A., Anis, B., & Eisa, W. H. (2020). Terahertz, Infrared, and UV–Vis Spectroscopy Study on Silver@ Polyaniline Core@ Shell Nanocomposites: Optical and Electronic Properties. The Journal of Physical Chemistry C, 124(33), 18243-18256.

Abstract

We present transmission measurements on silver@polyaniline (Ag@PANI) core@shell nanocomposites over a wide frequency range from terahertz to ultraviolet (0.001–6.2 eV). The Ag@PANI core@shell nanocomposites were prepared using solid-state reaction by mixing aniline sulfate (ANS) with 2.5, 5, 7.5, and 10 wt % AgNO₃. The nanocomposites were characterized by transmission electron microscope, ultraviolet/visible spectroscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The optical conductivity σ(ω) was fitted using the localization-modified Drude model together with the Lorentzian function. The incremental loading of AgNO₃ leads to an increase in the Drude conductivity (σ_LMD) and decrease of the scattering rate (γ_D) due to the increase of electron delocalization of protonated quinoid imine units. In addition, the densities of states N_EF at the Fermi level are increased from 1.7 to 2.7 per eV per formula unit, while the conduction bandwidth W is decreased from 0.7 to 0.4 eV with increasing the AgNO₃ from 2.5 to 10%. The optically determined band parameters suggest that the addition of AgNO₃ modifies the energy state of the Ag@PANI core@shell nanocomposites close to the Fermi energy modifying the half-filled polaron band.

Link