Development of a new solid-state absorber material for dye-sensitized solar cell (DSSC)

In contrast to the conventional DSSC systems, where the dye molecules are used as light harvesting material, here a solid-state absorber was used as a sensitizer in conjunction with the dye. The materials like ZnO and Al₂O₃ : C, which will show optically stimulated luminescence (OSL) upon irradiation were used as extremely thin absorber layers. This novel architecture allows broader spectral absorption, an increase in photocurrent, and hence, an improved efficiency because of the mobility of the trapped electrons in the absorber material after irradiation, to the TiO₂ conduction band. Nanocrystalline mesoporous TiO₂ photoanodes were fabricated using these solid-state absorber materials and after irradiation, a few number of samples were co-sensitized with N719 dye. On comparing both the dye loaded photoanodes (ZnO/TiO₂ and Al₂O₃ : C/TiO₂), it can be concluded from the present studies that, the Al₂O₃ : C is superior to ZnO under photon irradiation. Al₂O₃ : C is more sensitive to photon irradiation than ZnO and hence there can be more trap centres produced in Al₂O₃ : C.