Ying Yang and her colleagues supervised by Xing-Zhong Zhao at Wuhan University, China, are studying modification strategies to fabricate more stable dye-sensitized solar cell (DSSC) systems with PEO-PVDF based polymer electrolytes. One way of improving the conductivity of the polymer electrolyte and maintaining its stability, is to introduce a new continuous path for ion transportation. As the group explains, the cross-linking interactions between the liquid electrolyte and the polymer matrix is expected to form an ionic transport path of the quasi-solid state polymer electrolyte resembling that of a liquid system.

In a recent polymer electrolyte modification study, which was published in Nanotechnology, the authors used water and ethanol as cross-linking agents to improve the stability of quasi-solid-state DSSCs with PEO-PVDF electrolyte. The hydroxyl bonds present among PEO, TiO2, LiI and additives allow homogenous cross-linking networks to form in the electrolyte, which provide more efficient ion transport pathways. After optimization of the water and ethanol concentration, the best DSSC shows an energy conversion efficiency of about 5.8%, and is stable over 500 h when sealed with wax (see image for examples).

Zhao's group is currently focusing on the development of new polymer electrolyte systems such as polysaccharides, thermal setting and thermal plastic polymer electrolytes and ionic liquid electrolytes to drive up the performance and stability of DSSCs.