Study on Optical Constants and Refractive Index Dispersion of Neutral red Doped Polymer Film

Problem statement: The some optical constants polymer thin film with red dye 3-amino-7dimethylamino-2-methyl phenazine (NR) as the guest material and Polyvinylpyrrolidone (PVP) as the host material were prepared by adulteration and spin-coating methods. Approach: The values of some important parameters (refractive index n, extinction coefficient K and dielectric constant ε∞) of polymer thin film are determined from these spectra. Results: It has been found that the dispersion data obey the single oscillator relation of the Wemple-DiDomenico model, from which the dispersion parameters and high-frequency dielectric constant were determined. The estimation of the E0, Ed and ε∞ are 1.27, 3.175 and 3.5 eV respectively. Conclusion: The single oscillator model was used to calculate their optical constants from the transmittance and reflectance spectra. The dispersion of the refractive index in film follow the single electronic oscillator mode relation. The UV-Visible spectroscopic studies showed that, the NR film have high refractive index and high dielectric constant. The variation of the dielectric constant with the wavelength indicates that some interactions between photon and electrons in the films are produced in this wavelength range. These interactions are observed on the shapes of the real and imaginary parts of the dielectric constant and they cause the formation of peaks in the dielectric spectra which depends on the material type.