Theoretical Analysis on the Design of D–π–A Structured Dye-Sensitized Solar Cells Based on π-Bridge Modification in Different Donor Systems

In this work, fourteen D–π–A type dyes were designed by modulating donor substitution and π-bridge structures, featuring carbazole as the donor, coumarin as the π-bridge, and cyanoacrylic acid as the acceptor. Methoxy groups were introduced on the donor, while conjugated acetylene, ethylene, or thiophene linkers and cyano terminal groups were embedded in the π-bridge, enabling systematic tuning of the molecular electronic structure, absorption characteristics, and charge-transfer behavior.