Abstract
We developed a new strategy for the molecular engineering of organic D-pi-A sensitizers for dye-sensitized solar cell (DSSC) applications. Different from the synthesis of organic D-pi-A dyes by conventional C-C coupling method, the present approach highlights the construction of D-pi-A backbone via sequential condensation reactions. This approach avoids noble metal catalysis as well as harsh reaction conditions. Based on this concept, four organic D-pi-A dyes have been developed as sensitizers for DSSCs, which produced high IPCE values and photovoltage. Moreover, expansion of the pi-conjugated spacer in this type of dyes resulted in enhanced photovoltaic performance, which provided a new pathway for designing D-pi-A dyes.