Analysis of Absorbance Patterns and Functional Groups of BIO-Dye (Ocimum sanctum) Based on pH Variations in the Wet and Dry Extraction Method

Abstract

Bio-Dye is a dye derived from natural ingredients that have an important role in DSSC performance. This Bio-Dye is later in charge of absorbing sunlight entering the DSSC cells. Bio-Dye is a dye derived from natural ingredients that have an important role in the performance of the DSSC. This Bio-Dye is the one that will be in charge of absorbing sunlight entering the DSSC cells). One important key to know DSSC performance is to pay attention to the quality of the BIO-Dye. A good BIO-Dye can be seen by knowing the absorbance pattern and the function group of the dye its self. This research was conducted to determine absorbance patterns and functional groups based on pH variations in the wet and dry extraction methods contained in the Ocimum sanctum. The absorbance pattern was seen using a UV-Vis spectrophotometer and a functional group using FTIR. The chlorophyll pigment contained in the BIO-Dye (Ocimum sanctum leaf) was extracted using an ethanol solvent and added acetic acid to produce variations in pH values. The UV-Vis spectrometer measurement results showed the highest absorbance pattern was possessed by Ocimum sanctum dye in the dry extraction method and at natural pH (pH = 6.5). The peak absorbance they have is 648 nm, 614 nm, and 537 nm. The FTIR spectrum was obtained from Ocimum sanctum information containing the same functional groups when variations in pH values ​​were carried out in the wet and dry extraction methods. The functional groups are OH groups at wave number 3356.57 cm-1, CH at 2975.37 cm-1, C = O at 1652.50 cm-1, CN at 1383.81 cm-1, C = C at 880.25 cm-1, and CH absorbed at wave number 1087.78 cm-1. In general, it can be concluded that natural dye from Ocimum sanctum has a high absorbance in the visible light region and contains COOH compounds that can strengthen the bond of dye with TiO2 semiconductors so that Ocimum sanctum can be used as a dye in Dye-Sensitized Solar Cells (DSSC).