Two organic sensitizers (LI-40 and LI-41) containing 6,7-bis(hexyloxy)-2,3 dimethylquinoxaline unit andthiophene or furan as conjugated bridge were synthesized and utilized for dye-sensitized solar cells(DSSCs). The incorporation of quinoxaline unit brought about impressive changes in absorption spectraand energy levels, thus, enhanced the light-harvesting for photovoltaic conversion and facilitated theelectron transfer, resulting in a great improvement in the electron distribution of the whole molecule.The solar cell based on LI-40 exhibited a broad incident photon-to-current conversion efficiency (IPCE)spectrum and high conversion efficiency (h ? 6.75%). While under the same measuring conditions, thereference sensitizer PSS, which had similar structure to LI-40 but without the quinoxaline unit in theconjugated bridge, only gave the h value of 4.50%, indicating that the sensitizers are promising candidatesto improve the performance of DSSCs.
