Efficient quasi-solid-state dye-sensitized solar cells from graphene incorporated conducting gel electrolytes

Abstract

Aimed at enhancing the liquid electrolyte loading, ionic conductivity, and electrocatalytic activity toward iodides, a freeze-dried microporous polyacrylate–poly(ethylene glycol) (PAA–PEG) matrix was employed to uptake conducting substances, such as graphene, graphene oxide, and graphite. A liquid electrolyte loading of 21.1 g per g and a room-temperature ionic conductivity of 11.60 mS cm−1 were obtained from the PAA–PEG/graphene conducting gel electrolyte. The conducting substances can form interconnected channels within the insulating microporous PAA–PEG matrix, therefore, the reduction reaction of triiodide ions in the dye-sensitized solar cells (DSSCs) can be extended from the Pt/gel electrolyte interface to both the interface and three-dimensional framework of the microporous conducting gel electrolyte. The resulting DSSCs made from PAA–PEG/graphene, PAA–PEG/graphene oxide, and PAA–PEG/graphite exhibit power conversion efficiencies of 7.74%, 6.49%, and 5.63%, respectively, which are much higher than 5.02% exhibited by a pure PAA–PEG-based DSSC. This new concept, along with ease of fabrication suggests that microporous conducting gel electrolytes could be good alternative electrolytes for use in efficient quasi-solid-state DSSCs.