Optical properties of electron irradiated Bombyx mori silk fibroin films

Abstract

Energetic electron irradiation effects on the optical properties of Bombyx mori silk fibroin (SF) films are studied using UV–visible spectrophotometer. The recorded UV–visible absorption and transmission graphs have been used to determine the optical band gap (E g ), refractive index (n), extinction coefficient (k), optical conductivity (σ opt ) and dielectric constants (e *) of the films. The studies have shown a reduction in optical band gap and increase in refractive index with increasing electron dosage. It is also observed that dielectric constants increase with increasing photon energy. The observed optical changes have been tried to be correlated with the structural changes, revealed through FT-IR spectroscopy. These results indicate that the refractive index of SF films can be changed efficiently by electron irradiation.