New Pyridinium Ylide Dyes for Dye Sensitized Solar Cell Applications

Novel organic pyridinium ylide sensitizers (NO109–111) consisting of various anchoring groups were synthesized and characterized for applications in dye sensitized solar cells. Compared with the pyridine-<i>N</i>-oxide dye (NO108), the ylide sensitizers with strong electron-withdrawing acceptors exhibited dominant ultraviolet absorption properties and efficient binding abilities to the TiO₂ surface. Among these dyes, the pyridinium ylide NO111 sensitized solar cell showed the highest efficiency (5.15%), which was improved to 7.41% by employing coadsorbent chenodeoxycholic acid

Effect of Extended Conjugation of N‑Heterocyclic Carbene-Based Sensitizers on the Performance of Dye-Sensitized Solar Cells

We report the synthesis, characterization, and photovoltaic properties of four ruthenium complexes (<b>CI101</b>, <b>CBTR</b>, <b>CB111</b>, and <b>CB108</b>) having various N-heterocyclic carbene ancillary ligands, pyridine-imidazole, -benzimidazole, -dithienobenzimidazole, and -phenanthroimidazole, respectively. These complexes were designed to investigate the effect of extended conjugation ordained from ring fusion on the power conversion efficiencies of the solar cells. The device sensitized by <b>CB108</b>, the pyridine-phenanthroimidazole conjugated complex, showed an improved efficiency (9.89%) compared to those of pyridine-benzimidazole conjugated system (<b>CBTR</b>, 9.72%) and the parent unfused ring system (<b>CI101</b>, 6.24%). Surprisingly, the sulfur-incorporated pyridine-dithienobenzimidazole system (<b>CB111</b>, 9.24%) exhibited a little lower efficiency than that of <b>N719</b> (9.41%). The enhanced photovoltaic performance of <b>CB108</b> was mainly attributed to the increase in electron lifetime and diffusion length confirmed by the electrochemical impedance spectroscopy