Investigating the effect of various extracting solvents on the potential use of red-apple skin (Malus domestica) as natural sensitizer for dye-sensitized solar cell

In the current investigation, the natural dye extracted from red-apple (Malus domestica) skin was used as natural sensitizer for dye sensitized solar cell (DSSC) application. The present study was specifically aimed at observing the effect of different solvents, i.e. deionized water, ethanol, and acidified ethanol, on the performance of the natural dye and thus the DSSC. For synthesis purposes, red-apple skin was peeled off, dried, crushed and furthermore extracted with ratio red-apple skin powder to solvent 1:20 w/v for 2 hours at 50°C under mechanical stirring. Subsequently, the resulting natural dyes with different solvents were examined by Fourier transform infrared (FTIR) to analyze their functional groups, UV-Vis spectroscopy to observe their absorption spectra for a wide range of wavelength, while TiO₂ nanoparticle used as the semiconductor oxide layer in the device was characterized by field emission scanning electron microscope (FESEM). The FTIR results showed that the red-apple skin has anthocyanin group which functions as the sensitizer agent for photon energy absorption from the sunlight. The UV-Vis spectroscopy results showed that ethanol solvent has higher absorption of sunlight wavelength as compared to those of deionized water and acidified ethanol solvents. The performance test of the fabricated DSSC showed the prototype made of the red apple skin dye extracted by ethanol solvent can provide the highest open circuit voltage (V_oc) up to 324?mV and efficiency around 0.046%. On the basis of investigation, it has been found that ethanol was the best solvent to extract anthocyanin from the red-apple skin.