Optical Characteristics of Nickel Oxide Thin Films Doped with Dye Extract from Three Natural Dyes

Abstract

Nickel Oxide (NiO) has displayed useful properties for application in solar cells, sensors, optoelectronics, and coatings. Modifying NiO with natural dyes has the potential to enhance its performance in these areas. This study deposited Nickel Oxide thin films with dye extract from Eupatorium Odorata, Ageratum conyzoides, and Pucro Pueraria using a chemical bath technique. The dye extraction was carried out at a constant temperature.  The thin films are characterized using RBS, XRD, and SEM, and the optical properties of the films are investigated using various analytical methods. Transmittance and Reflectance data were used to calculate the film's optical constants such as refractive index, extinction coefficient and film thickness. Results showed that transmittance decreases with the doping of dyes in the UV region and is high in the VIS-NIR region, while reflectance is low in all spectral regions. The films show very high absorbance in the UV region, moderate in the VIS region and low in the NIR region. The band gap value was found to be 4.00eV, 3.83eV, 3.95eV, and 3.85eV for the as-grown NiO doped with Dye extract from leaves of Eupatorium Odorata, Ageratum conyzoides and Pucro Pueraria respectively. The extinction coefficient of the layer doped with dyes is higher compared to the as-deposited layer. The incorporation of dyes into the film matrix altered the real dielectric spectra of the as-deposited films and could be deployed in optoelectronics, coatings, or other fields.