To maximize dye absorption and improve energy conversion efficiency, we adopted a branched structure for single crystalline ZnO nanowires in dye-sensitized solar cells (DSSCs). The high-density branched structures of these ZnO nanowires were incorporated by a two-step seeding with zinc acetate dihydrate seeds. The ZnO nanowire DSSCs exhibited an overall efficiency of similar to 0.46%. This represented a 35% improvement compared to the ZnO nanowire DSSCs with pillar-shaped ZnO nanowires. Our current density-voltage (J-V) characterizations suggest that the current densities and power conversion efficiencies were improved by increasing the surface area with these branched structures of ZnO nanowires in DSSCs. (c) 2007 Elsevier B.V. All rights reserved.