Co-sensitizer dyes from Eucheuma cottonii sp. and Hylocereus polyrhizus sp. by the hybrid approach as a photoactive layer in solar cell application

Co-sensitization approach of natural dye as photosensitizer layer in dye-sensitized solar cell (DSSC) was extensively explored in association with development of single dye sensitization. The low pricing and the abundant source of natural dye added with the ecology and environmentally friendly policy has successfully convinced the researchers that the co-sensitizer dyes in DSSC is one of the great options. Natural dye materials from fruit and plant contain natural compounds such as anthocyanin, betacyanin, chlorophyll possess great impact in the photon energy absorbance for electron excitation in Fermi layer towards high energy conversion. To date, extensive research has focused on the electron configuration in dye compound for further potential discover as photo sensitizer candidates. Co-sensitization of dyes was introduced earlier on and proved its feasibility as potential photosensitizer candidates. Hylocereus polyrhizus (Dragonfruit, D) and Eucheuma cottonii (seaweed, E) were selected as photosensitizer and some modification of its ratio mixing were carried out. Few characterizations were done to further analyze photosensitizer properties. Overall result obtained proved that by tuning dye ratio will induce shift on absorbance spectrum and alteration of energy band gap (Eg) value from 2.14 eV from D to 2.09 eV, 2.12 eV, 2.13 eV of 1D : 10E, 1D : 100E and 30D : 1E respectively. FT-IR result obtained showed the presence of betacyanin and chlorophyll group with the presence of C=O, C-H, O-H functional group and the thermal stability of dye compound were evaluated by TGA analysis. Further characterizations on energy conversions was carried out using four point probe and potentiostat measurement exhibited that solar cell efficiency (ŋ) of D, E, 1D:10E, 1D:100E and 30D:1E were 0.7%, 0.8%, 0.9%, 0.5% and 0.3% respectively. This study highlighted that the co-sensitization is a great approach in the enhancement of DSSC overall performance, compared to individual dye. It is recommended that further study should be carried out in order to optimize its potential in DSSCs.