Optical constants, dispersion parameters and energy loss functions of crystal violet as a potential absorber thin film for solar energy conversion and storage applications

Abstract Highly homogenous crystal violet (CV) thin films are grown by spin coating technique. X-ray diffraction (XRD) measurements have been carried out to identify the dominant orientation of the films. The XRD pattern of as-deposited film showed an amorphous structure which turns into nanocrystalline by thermal annealing at 150 °C for 1 h. The spectroscopic characterization of as-deposited and annealed CV films was estimated via spectrophotometric measurements of transmission and reflection in the spectral range 190–2000 nm. Optical constants of CV films were determined. Wemple-DiDomenico model was applied to the normal dispersion region of refractive index spectrum and from which, many dispersion parameters were calculated. The type of most probable transitions and values of optical energy gaps for CV films were estimated by Tauc plot. The dissipation energy and volume & surface loss functions were estimated. The influence of annealing temperature on the spectroscopic properties, dispersion parameters and energy loss functions were investigated which revealed an improvement in the optical properties and decreased values of energy loss functions for the annealed CV films. The obtained results of optical features for CV films reveals that CV films are an excellent potential absorbing material in solar energy conversion and storage devices.