Synthesis and Photovoltaic Performance of Long Wavelength Absorbing Organic Dyes for Dye-Sensitized Solar Cells

We prepared novel organic photo-sensitizers based on a carbazole framework containing various acceptors with thiophene bridge units in the chromophore for the application to dye-sensitized solar cell (DSSC). Furthermore, organic dyes without bridge in the chromophore also synthesized to investigate the correlation between conjugation lengths and photon-to-current efficiency (PCE). Compared to non-bridged dyes, the DSSCs device containing multi-anchoring dyes with thiophene bridge exhibited much higher PCEs, resulting from efficient electron extraction pathways, higher molar extinction coefficients, and better light absorption in longer wavelengths.