Kappaphycus alvarezii sp., Sargassum polycystum sp. and Manihot esculenta sp. as photo-sensitizers in dye-sensitized solar cells

Quah Soon Wei,Khairul Nizar Syazwan Wan Salihin Wong,Ashma Diyanti,Muhammad Fahmi Aizat,Hasyiya Karimah Adli,Wan Mohd Faizal Ishak,Hasiah Salleh

doi:10.1063/1.5089327

Abstract

Several advantages of natural plant-derived dyes such as low cost, abundant in supply, sustainability and environmentally-safe make this type of dyes are widely investigated as photo-sensitizers. These dyes are known containing natural compounds (e.g. carotenoids, chlorophylls, anthocyanins) that have electronic delocalization in extended π-orbital system for electronic transfer mechanism. To date, a number of research works were reported to extend the potential of natural dyes as photo-sensitizers in dye-sensitized solar cells (DSSCs). In regard to this matter, extracted dyes from Kappaphycus alvarezii sp., Sargassum polycystum sp. and Manihot esculenta sp. denoted as K, S and C respectively were successfully prepared and several physical characterizations were carried out to analyse their photo-sensitizer properties. From UV-vis and tauc plot, it was found that all extracted dyes exhibited the absorption of wavelength in visible spectrum, concluded the ability of K, S and C as photo-sensitizers with bandgap values of 2.85, 2.41 and 2.10 eV, respectively. SEM surface morphology of C exhibited smooth surface with the existence of long chain of small particles, while S has bigger particles with few pinholes and K showed full coverage of rough surface. From BET analysis, C has highest specific surface area, SBET(5.16 m2g-1) and mesopore volume (0.007 cm3g-1) compared to other dyes, which may contribute to higher adsorption of C particles on TiO2 surface during dye sensitization. Overall solar cell performance of ITO/TiO2/dyes (K or S or C)/carbon obtained was found in similar trends with bandgap and conductivity, with PCE values of C, S and K are 0.6%, 0.18% and 0.06%, respectively. In summary, this study highlighted the promising photo-sensitizer properties of C, S and K for solar cell application and significant factor of specific surface area of dye particles for better solar cell performance of DSSCs.

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