Organic Sensitizers with Bridged Triphenylamine Donor Unit: A DFT Study

The P-series of dyes have been designed and theoretically characterized through DFT and TD-DFT to systematically explore the underlying physical origin of the bridged TPA donor unit and to investigate its influence on DSSCs. Key parameters associated with the solar cell performance were characterized and analyzed in detail. The results indicate that the methylene-bridged TPA group not only enhances the planarity of the donor group while effectively lowering λtotal and EBE, thereby elevating the Jsc, but also promotes Voc due to differences of μnormal. Furthermore, the design strategy of the bridged TPA group has been explored preliminarily. A TPA donor group bridged by an N atom or group is favorable for both Jsc and Voc. Lastly, the newly designed dye P12 combines the virtues of both C-bridged and N-bridged groups, demonstrating outstanding Jsc and Voc among all P-series dyes. This finding further validates the correctness of previous conclusions, and P12 emerges as the best alternative dye molecule in this work.