The long-term stability of dye-sensitized solar cells (DSCs) based on an amphiphilic ruthenium sensitizer, CYC-B6L was studied. When the surface of the TiO2 electrode was passivated with a coadsorbent, chenodeoxycholic acid (CDCA), the resulting DSC reveals very good long-term stability with over 87% of initial performance under a 1000 h prolonged light-irradiation and thermal stress (60 degrees C) aging, which is as good as the state-of-the art robust device. The solvent used in dye bath also affects the long-term stability of the DSC devices. The effect of co-adsorbent and the impact of the dye bath solvents on the device durability were investigated using the electrochemical impedance spectroscopy. (C) 2012 Elsevier B.V. All rights reserved.