Optical absorption spectroscopy of the blackberry dye applied in solar cell sensitizers and gamma radiation effects.‎

Abstract

This paper is a part of natural dye solar cell project. The dye extracted from blackberry fruit is successfully used in the ‎fabrication of natural dye sensitized solar cells (NDSSC). Blackberry dye extract is showed to contain anthocyanins which is ‎an excellent light harvesting pigment needed for the generation of charge carriers for the production of electricity. A strong ‎absorbance in the green region (520 nm) is observed for blackberry dye at pH 1. The color intensity of the blackberry dye is ‎decreased with the gamma dose up to 5 kGy and then saturation started. The high absorption range is found in blackberry ‎dye 360-750 nm. The absorption band edge value of the natural dye solutions of the blackberry is found 1.97 eV from the ‎maximum peak position (at wavelength 630 nm). Tauc gap (Eg) of the blackberry dye is found 1.96 eV for direct transition. ‎It is observed that the gamma dose up to 7 kGy showed no significant effect on both absorption edge and Tauc gap of ‎blackberry dye. The particles sizes range of the blackberry dye form the blackness pigment is found to 0.6-3.0 and 0.4-1.0 ‎microns in diameter before and after gamma radiation. The optimum conditions of NDSSC based on this study of Blackberry ‎dye are found that VOC=0.5, JSC =0.7 mA.cm-1, FF=0.5, and η %=0.2.‎