Doctor Blade Casting of Thin Films Containing Different Concentrated Endemic Plant Extracts: Determination of Structure and Optical Properties

Abstract

This study provides a thorough properties of the optical analysis of the thin films which produced from Astragalus tokatensis Fisch., Helichrysum noeanum Boiss. and Stachys huber-morathii R. Bhattacharjee extracts. Methanol extracts of plants were obtained via Soxhlet extractor. The highest extract yield (10.10%) was determined in H. noeanum. Doctor blade coating method is used to make thin film layer on glass substrate. The optical behavior of the deposited films is tested by means of he UV-vis-near IR absorbance and transmittance characterization. It is found that the maximum transmittance spectra reaches nearly to a value of 90 % for A. tokatensis sample. Significantly, all the samples display same optical absorbace spectra behavior. Energy band gaps of the films are presented based on Tauc relation and were found to be in the range between 3.68-3.81 eV. Besides, the analysis of functional groups available in the materials is broadly studied by Fourier transform infrared (FT-IR) spectroscopy. FT-IR measurement also confirms that all produced films have carbohydrate pattern. These findings demonstrate a cost-efficient approach for the production of thin films with plant extraction, and open a new perspective on the potential applications of optoelectronic devices.