Effect of concentration of red dragon fruit (Hylocereus costaricensis) peels extract as a dye of dye-sensitized solar cell (DSSC) on DSSC efficiency

Abstract

The utilization of red dragon fruit peels (Hylocereus costaricensis) as a DSSC sensitizer has been done to study the effect of extracted dye concentration on DSSC efficiency. DSSC has four main components, namely working electrode, sensitizer, a counter electrode, and electrolyte. One of the most essential components in DSSC is a sensitizer. In this work, variations of concentration of dye extracted were carried out to obtain an optimal concentration of dye so that TiO2 could fully absorb molecular dyes. The dye solution was extracted by dissolving the red dragon fruit peels into methanol, acetic acid, and aquades. Variation of concentration used was 5g/20mL; 10g/20mL; 15g/20mL; 20g/20mL; 25g/20mL; and 30/20mL (b/v). Optical properties of dye solution and TiO2/dye layer was characterized by UV-Vis spectrophotometer, functional groups of TiO2/dye layer was characterized by Fourier Transform Infra-Red (FTIR), and current-voltage of DSSC was characterized by Keithley I-V Meter. Extracted dye results show optical absorption at a wavelength of 450-550 nm, which has a peak that tended to increase with increasing concentration. Meanwhile, the absorption spectrum was obtained from Fourier Transform Infra-Red (FTIR) shows the presence of functional groups O-H, C=O, C=C, C-O, and C-H aromatic. The results of DSSC current-voltage characterization obtained an efficiency of 0.047% at a concentration of 20g/20mL; this was supported by the highest absorbance of TiO2 films which dye coated at a concentration of 20g/20mL.