Absorption, dispersion, and emission characteristics of novel Chitosan blends thin films tuned by UV-Ozone

In current study, two novel polymers derived from original Chitosan is synthetized. Polymeric blends from Chitosan and the new polymers are used to fabricate spin coated thin films. The effect of UV irradiation on the optical properties of pristine Chitosan and two novel Chitosan derived polymers blends in form of thin film structure are studied. The optical parameters of the blends thin films such as the refractive index (n), extinction coefficient (k) and dielectric constants are determined by spectrophotometric technique in the spectral range 200–2500 nm. The energy gap values (Eg), dielectric constants at infinity (ε∞), lattice permittivity (εL) and dispersion parameters are calculated. Eg is found to be 5.14 eV for Chitosan film and it is reduced to 4.25 and 4 eV for the two polymeric blends. ε∞ is calculated to be 2.96 for Chitosan film which is reduced to 2.88 upon UV irradiation. The influence of exposing thin films to UV light demonstrates interesting modifications in linear and nonlinear optical properties (third order non-linear susceptibility and the non-linear refractive index) of Chitosan and its derivatives. The emission characteristics of the blends are also investigated. The fluorescence intensity of the polymeric films is decreased upon UV exposure. The obtained results propose that Chitosan and its derivatives are possible candidates for opto-electronic applications such as optical switching, optical limiters and OLED.