Lamellar conducting channels constructed by lyotropic liquid crystals as quasi-solid-state electrolytes toward dye-sensitized solar cells†

Abstract

Developing high-performance electrolytes combining high efficiency and durability remains challenging for energy devices. Herein, lyotropic liquid crystal (LLC) electrolytes (Brij58-LLC_n) were designed for quasi-solid-state dye-sensitized solar cells (DSSCs) based on commercially available polyethylene glycol-20-hexadecyl ether (Brij58) in combination with different weight contents (30%, 40%, and 50%) of a liquid electrolyte (LE). The liquid crystal behavior, molecular arrangement, electrochemical performance, and DSSC performance of Brij58-LLC_n were investigated. Self-assembly of Brij58 and a LE formed a lamellar phase with a focal conic texture. The LE was concentrated to construct layered conducting channels and these channels were expanded by increasing the LE, which was beneficial for charge transfer. The best ionic conductivity of 9.01 mS cm⁻¹ was achieved by Brij58-LLC₅₀. DSSCs containing Brij58-LLC_n exhibited promising photovoltaic performance and satisfactory thermal stability. The introduction of commercial Brij58 has extended the path of constructing ‘liquid’ channels in lyotropic liquid crystals for enhancing the performance of energy devices, which provides new ideas for the development of electrolytes in advanced energy devices.