Abstract:

In order to discuss the differences in the performance of dye-sensitized solar cells(DSSCs) based on two D-π-A organic dyes, which only differ in the donor part, theoretical parameters closely related to the short-circuit photocurrent density(J_sc) and the open-circuit photovoltage(V_oc) were computed with the density functional theory(DFT) and time-dependent DFT calculations, including absorption spectrum, light harvesting efficiency, injection driving force, vertical dipole moment and number of photoinjected electrons and so on. The results reveal that the lower dye regeneration efficiency of dye 2 lead to the lower J_sc of DSSCs, when the dyes have comparative light harvesting efficiency and electron injection efficiency. Meanwhile, under the condition that the dyes have comparative number of photoinjected electrons and the extent of charge recombination, the higher vertical dipole moment of dye 1 could be the crucial factor leading to the higher V_oc. The calculated results are in good agreement with the experimental one. Finally, we hope that our results could provide certain guidance for the future works on the synthesis and design of new efficiency dyes.

Key words: Dye-sensitized solar cell, D-π-A organic dye, Light harvesting ability, Dye regeneration efficiency, Density functional theory