Photoelectrochromic devices: Influence of device architecture and electrolyte composition

Solar energy harvesting and chromogenic technologies can be integrated together to give self-powered and wireless photoelectrochromic devices (PECD). Due to the similarity in the architecture of both dye-sensitized solar cells (DSC) and electrochromic devices (ECD), it is possible to merge these two devices into one combined solar-powered electrochromic device known as DSC-EC. The present work describes the preparation and characterization of electrochromic solar cells using PEDOT:PSS (poly(3,4-ethylenedioxythiophene) polystyrene sulfonate) as electrochromic material in the counter-electrode. Different configurations and liquid and polymer-based electrolytes are studied. The resulting electrochromic solar cells were characterized focusing on the determination of solar to electricity conversion efficiency and the color contrast was assessed using color coordinates under simulated solar irradiation. The best DSC-EC configuration originates a color contrast of (ΔE = 30) at a potential difference of 0.4 V and energy conversion efficiency of 4.9% at VOC of 0.66 V and JSC of 11 mA cm−2, when using the liquid electrolyte. On the other hand, the best performing DSC-EC using the polymer-based electrolyte showed a very good color contrast of (ΔE = 47) at short circuit and an energy conversion efficiency of 1% at VOC of 0.63 V and JSC of 4.5 mA cm−2.