A new organic dye (named L1) containing butoxy group as donor was designed and synthesized. Treatment of 4-bromophenol with n-BuI and B(OCH₃)₃ gave the boronic acid. The intermediate aldehyde was prepared from bis-thiophene via bromonation reaction with N-bromosuccinimide (NBS) and Vilsmeier-Haack reaction. The dye was synthesized from the Suzuki coupling reaction of the boronic acid with the aldehyde, followed by Knoevenagel condensation reaction with cyanoacetic acid. The dye was applied to nanocrystalline TiO₂ dye-sensitized solar cells through standard operations. For a typical device the maximal monochromatic incident photon-to-current conversion efficiency (IPCE) can reach 62%, with a short-circuit photocurrent density (J_sc) 6.4 mA•cm^－2, an open-circuit photovoltage (V_oc) 535 mV, and fill factor (FF) 0.60, which corresponds to an overall conversion efficiency of 2.1%.

Key words: dye-sensitized solar cell, photovoltaic, organic dye, cyclopentadithiophene, alkoxyl group