The photoelectrochromic window represents a special kind of self-powered smart window: it can change transmittance using electrical energy that itself converted from solar energy. In this paper, we report a novel photoelectrochromic device based on an electrochromic film of poly(3,4-(2,2-dimethylpropylenedioxy)thiophene) we synthesized and an organic ruthenium complex dye. The addition of a thin layer of platinum under the electrochromic layer to act as a catalyst allowed the assembled device to perform with fast response times (one and four seconds for coloring and bleaching, respectively) and with a 38% transmittance difference between the two states. The electrochemical impedance study also indicated that the device has dual application of color-change and energy-harvest. (C) 2011 Elsevier B.V. All rights reserved.