A composite electrocatalytic poly(3,4-ethylenedioxythiophene) film incorporated with silver nanowires for bifacial dye-sensitized solar cells

Poly(3,4-ethylenedioxythiophene) (PEDOT) is a superior electrocatalyst for dye-sensitized solar cells (DSSCs). The porous PEDOT film, however, lacks directional conduction paths, resulting in slower electron transfer and lower cell efficiency. In this study, silver nanowires (Ag NWs) are incorporated into a PEDOT film to construct a PEDOT-coated Ag NW composite film, wherein the Ag NWs serve as highways for charge transport. The composite film is constructed by spreading Ag NWs on tin-doped indium oxide (ITO) glass via a three-step process (dip coating, brush painting, and thermal compression), followed by coating a PEDOT film via electropolymerization. The DSSC catalyzed by the PEDOT-coated Ag NW exhibited an efficiency of 9.22 % under one-sun illumination, outperforming platinum (9.09 % efficiency) and PEDOT (8.33 % efficiency) by increasing the short-circuit current density. Chemical state analyses were performed to determine the interactions between the Ag NWs and PEDOT. Impedance measurements and quantum chemical calculations were conducted to rationalize the functionality of the PEDOT-coated Ag NWs. Owing to its high transparency, the resulting DSSC achieves an efficiency of 6.74 % under rear illumination, demonstrating its high feasibility as a bifacial DSSC. The DSSC also exhibited high efficiencies ranging from 14.05 % to 19.69 % under front-side illumination at low intensities of 300–1000 lux.