Kappaphycus alvarezii, Sargassum polysystum sp. and Manihot esculenta sp. as PhotoSensitizers in Dye-Sensitized Solar cell

The energy crisis is a worldwide serious issue as the increasing demand of non-renewable sources for industrial and urbanization. The use of limited non-renewable sources such oil and fossil fuels undergoes rapid depletion and they cannot survive as primary sources to keep up with energy demand worldwide. Therefore, to overcome the problem on the energy sources depletion, the researchers have discovered the use of renewable sources, such solar energy. The use of extracted natural dyes as photo-sensitizers in dye-sensitized solar cell (DSSC) has been proven and studied by many researchers. The advantages of these natural dyes such as low cost production, abundance, and environmental friendly were considered. Previous study highlighted the presence of chlorophyll in photo-sensitizers of DSSC. The natural dye extract from Kappaphycus alvarezii sp. (red algae) (K), Sargasum polysystum sp. (brown seaweed) (S) and Manihot esculenta sp. (cassava) leaf (C) was successfully prepared and characterized to determine the photo-sensitizer properties. The analysis involved were UV-vis spectroscopy (UV-vis), Scanning electron microscopy (SEM), Brunauer-Emitte-Teller (BET) and four point probe (4pp). It was discovered that from Tauc plot measurement, the band gap value of C has the smallest value followed by S and K with 2.10 eV, 2.41 eV and 2.85 eV respectively. The conductivity shows that C has the highest conductivity value followed by S and K with 2.70 E -4 (Scm-1), 2.64 E -4 (Scm-1) and 2.34 E -4 (Scm-1) respectively, which has similar trend with the band gap value. The solar cell performance values were determined in which C has the highest solar efficiency followed by S and K with 0.60 %, 0.18 % and 0.06 % respectively. The result from the surface area analysis indicate that with 5.16/m2g-1, C has the highest specific surface area followed by K and S with 2.37/m2g-1 and 1.84/m2g-1 concluded that the higher specific area could lead to maximize dyes sensitization and thus increase better solar cell performance. Overall, the use of natural dye as photo-sensitizers in DSSC successfully achieved and the study highlighted the importance of specific surface area of dyes for higher solar cell efficiency.