Diphenyldibenzofulvene‐Based Sensitizers for Efficient Dye‐Sensitized Solar Cells: The Tuned Absorption Properties and Partially Suppressed Aggregation

Three new organic sensitizers (LI-62, LI-63, and LI-64) were designed and synthesized, in which the diphenyldibenzofulvene (DPDBF) π-bridge was structurally modified by introducing different groups to its phenyl rings to fine-tune the electronic properties. Accordingly, the light-harvesting capabilities, energy levels, and photovoltaic performances were systematically investigated. The three-dimensional configuration of DPDBF can weaken the intermolecular interactions, and, thus, benefit the orderly arrangement of the dyes onto the TiO2 surface. In comparison to LI-62, which contained the electron-withdrawing CF3 group as a substituent on the DPDBF moiety, LI-64 with the electron-donating SMe group exhibited a higher molar extinction coefficient and IPCE value, which directly led to a higher conversion efficiency and provided some useful information for the optimization of organic dyes that have a high photovoltaic performance.