Improved stability of unsealed quasi-solid-state dye-sensitized solar cell using poly(3,4-ethylenedioxythiophene) film as layer electrolyte

Quasi-solid/solid polymer electrolytes have been the subject of extensive research for an alternative of liquid electrolyte for dye-sensitized solar cells (DSSCs) because of their advantages such as alleviated leakage, lower environmental impact and ease of device fabrication. In this work, the performance of the unsealed quasi-solid-state DSSCs based on composite poly (ethylene oxide) (PEO) electrolyte and N719 dye-sensitizer was examined on aging under atmospheric condition. The energy conversion efficiency of DSSC using the composite PEO electrolyte was 5.62 % under sun simulated light, AM 1.5 (100 mW cm^-2) but gradually decreased to 0.95 % on aging for 90 days. An additional layer of poly(3,4-ethylenedioxythiophene) (PEDOT) electrolyte was incorporated with the composite polymer electrolyte for DSSC fabrication. The PEDOT layer was prepared by electrochemical polymerization of bis-ethylenedioxythiophene (bis-EDOT) and characterized by Raman spectroscopy and cyclic voltammetry. It was found that the energy conversion efficiency of DSSC based on the composite polymer electrolyte incorporated with PEDOT layer was 5.57 % and gradually decreased to 1.76 % under the same aging condition. Thus an additional layer of PEDOT electrolyte provided an improved stability of DSSC.