Six different rigidifying modes of dithiophene π-spacer in organic D-π-A sensitizers(1-6)were taken into account to provide insight into this rigidification effects on the performance of dye sensitized solar cell(DSSCs)through density functional theory and time-dependent density functional theory calculations[1].The calculated results demonstrated that this rigidification has significant effects on the light harvesting,charge recombination and conduction band energy shift,which are important factors affecting the efficiency of the DSSCs.It is found that dye 3 with rigidification via methylene is expected to have the best performance among these dyes,since it presents largest theoretical short circuit current density,and conduction band energy shift and similar charge recombination degree as compared to other rigidifying modes and dithiophene.For dye 4 with rigidification via phosphine oxide group,it also has the red-shifted adsorption,and the much longer I2-TiO2 distance could also lead to a slower recombination.Thus,the rigidifying modes in sensitizers 3 and 4,which have never been used in organic sensitizers for DSSCs,could be promising building blocks for high-performance sensitizers.