Dye-sensitized solar cell (DSSC) is a promising solution to global energy and environmental problems because of its merits on clean, low fabrication cost, relatively high power conversion efficiency, good durability, and easy assembly. However, the commercial application of DSSCs has been hindered by the high expenses of counter electrodes (CEs). With an aim of significantly enhancing the light-to-electric power conversion efficiency, here we pioneerly synthesize CoPt alloys using an electrochemically codeposition technique which are employed as CEs for efficient DSSCs. Owing to the rapid charge transfer, electrical conduction, and electrocatalysis, power conversion efficiencies of CoPt alloy CE-based DSSCs have been markedly elevated in comparison with that of the DSSC from Pt-only CE. The DSSC employing CoPt0.1 alloy CE gives an impressive power conversion efficiency of 9.59%, which is much higher than 6.86% from conversional Pt-based DSSC. The high conversion efficiency, low cost in combination with simple preparation, and scalability demonstrates the potential use of CoPt alloy CEs in efficient DSSCs. (C) 2014 Elsevier B.V. All rights reserved.