Improving interfacial electron transfer and light harvesting in dye-sensitized solar cells by using Ag nanowire/TiO2 nanoparticle composite films

Abstract

Metallic Ag nanowires coated with a TiO₂ nanolayer (AgNWs@TiO₂) were employed as electron conductors in the mesoporous photoanodes (developed by TiO₂ nanoparticles, P25) of dye-sensitized solar cells (DSSCs). Our results demonstrate that the AgNWs@TiO₂ (in an optimized content of 3 wt% in the photoanode) improved the energy conversion efficiency (η) of the DSSC from 4.68 to 5.31% compared to the DSSC without AgNWs@TiO₂ (pure P25). Such an improvement could be mainly attributed to the reduced TiO₂/dye/electrolyte interfacial charge transfer impedance. To our surprise, the surface plasmon resonance (SPR) and light scattering effects of the nanowires were found to substantially boost the incident photon-to-electron conversion efficiency (IPCE) of such DSSCs. Regardless of the assembly techniques, our results demonstrate the possibilities of developing the photoanode with reduced interfacial impedance and superior light harvesting capability compared to the existing photoanodes in similar configurations by appropriately adjusting the AgNWs@TiO₂ content in the photoanode with P25 based composites.