Long-term stability of dye-sensitized solar cells using a facile gel polymer electrolyte

Herein, we demonstrate a facile low temperature approach to prepare a gel polymer electrolyte (GPE) based on the triiodide/iodide redox couple in a quasi-solid-state dye-sensitized solar cell (DSSC). Only one polymeric agent ( i.e. , hydroxypropyl cellulose (HPC)) is used for the preparation of a non-volatile GPE system for the standard liquid electrolyte containing 1-methyl-3-propylimidazolium iodide (MPII). The prepared GPE completely penetrates into a TiO 2 photoanode at room temperature due to the uniform distribution of Ti, Ru and I elements in the cross-section of the electrode, forming an interpenetrating GPE/TiO 2 network to access all dye molecules. The GPE with the optimum HPC : MPII weight ratio shows a high ionic conductivity of 17.8 × 10 −3 S cm −1 and a viscosity of 350 cP. The DSSC fabricated using such gel polymer electrolyte shows the best performance and energy conversion efficiency of 7.44%, with a short-circuit current density, an open-circuit voltage and a fill factor of 15.37 mA cm −2 , 707 mV and 68%, respectively. The constructed quasi-solid-state cell has long-term operational stability under realistic outdoor conditions, with 90% of the initial device's efficiency after 600 h. Hydroxypropyl cellulose as a polymeric gelator agent was incorporated in the liquid electrolyte of dye-sensitized solar cells, showing long-term stability and efficient performance.