An efficient and thermally stable dye-sensitized solar cell based on a lamellar nanostructured thiolate/disulfide liquid crystal electrolyte and carbon/PEDOT composite nanoparticle electrode

Abstract

A thiolate/disulfide redox based lamellar nanostructured smectic liquid crystal electrolyte with an optimized configuration and a carbon/PEDOT composite nanoparticle electrode were prepared for efficient dye-sensitized solar cells (DSSCs). The configuration of the optimized electrolyte consisted of 1-dodecyl-3-methyl-1H-imidazol-3-ium 1-methyl-1H-tetrazole-5thiolate/di-5-(1-methyltetrazole) disulfide/TBP/LiClO₄ in the molecular ratio of 2 : 1 : 1 : 0.1. The carbon/PEDOT composite electrode was developed by electrochemical deposition of PEDOT on a carbon nanoparticle electrode. The additives in the lamellar nanostructured electrolyte were revealed to lower the viscosity of the electrolyte for promoted ion diffusion, as well as benefit the charge transfer process in the DSSC. The carbon/PEDOT nanoparticle electrode was suggested to provide improved catalytic activity and large surface area to favor the charge transfer at the cathode/electrolyte interface of the DSSC. As a result, the DSSC fabricated using the optimized smectic electrolyte, the composite nanoparticle electrode, together with a Z907 sensitized photoanode, attained a maximum power conversion efficiency of 6.5% at 40 °C and stable efficiencies higher than 6.0% within a temperature range from 35 to 55 °C. These results show potential of the optimized smectic thiolate/disulfide electrolyte based DSSCs operating efficiently and stably under outdoor conditions.