High-performance/low-temperature-processed dye solar cell counter electrodes based on chromium substrates with cube-like morphology

There is still an open question of how to prepare high-performance counter electrodes for dye solar cells (DSCs) at room temperature; a requirement for flexible DSCs. Here, we introduce Pt deposited cube-like chromium coating as a low-temperature highly-efficient counter electrode for DSCs. Cr is a chemically stable metal and can be easily electroplated on conductive substrates with high roughness (here similar to 160 nm) and cube-like appearance. A cyclic electrochemical deposition method with optimized temperature and number of cycles is used to grow Pt nanoparticles on this surface and charge transfer resistance as low as 0.54 Omega cm(2) and 0.27 Omega cm(2) were obtained at 40 degrees C and 55 degrees C solution temperatures, respectively. More surface defects (kinks, terraces and ledges) on the cube-like chromium film, as well as the electric field enhancement near the cube edges produces more dispersed Pt nanoparticles on this substrate compared to FTO (fluorine doped tin oxide) substrate. By replacing the conventional DSC counter electrode (thermal Pt on FTO) with this new electrode, filling factor and efficiency increase from 0.63-6.6% to 0.68-8.77%, without a scattering film. The efficiency can be as high as 9.52% by using a scattering film. (C) 2014 Elsevier B.V. All rights reserved.