Stability of polymer electrolyte-based dye-sensitized solar cells

5 Stability of polymer electrolyte-based dye-sensitized solar cells 

The stability of DSSC with polymer electrolytes is very important, although few studies involving this issue can be found. One of the motivations for the substitution of the liquid electrolyte is that the use of a solid electrolyte can minimize leakage and solvent evaporation problems and provide longterm stability, thus extending the life of the devices. At the same time, many 

22 Variation of ( ) l, ( ) V and ( ) t] as a function of time for a DSSC assembled with a polymer electrolyte, exposed to direct sunlight for 1 h each day (at noon). 4c values stabilize within 20 days, while C keeps decreasing for 40 days. The efficiency behavior seems to be determined by the 4c characteristics. 

Some authors reported the stability of DSSC assembled with polymer electrolytes with different compositions and related this behavior to the properties of the electrolyte. For example, solar cells were assembled with electrolytes combining the ionic liquid l-methyl-3-propylimidazolium iodine and PEO, poly(propylene oxide) or the copolymer poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide). After introducing less than 10 wt% of the polyether into the liquid electrolyte, the parameters of these quasi-solid state solar cells were still comparable to those of the liquid photochemical cells. It was believed that the polymer can contribute to the maintenance of the efficiency of the solar cells by holding the organic solvent. All devices were sealed with paraffin wax. The cell assembled with liquid electrolyte lost half of the conversion efficiency after 5 days, while the cells fabricated with the polyether-electrolytes had 

The stability of other polymer and gel electrolytes based on PEO and PVDF derivatives have also been investigated. So far, most studies involving the stability of polymer electrolyte-based DSSC show the benefit of the replacement of the liquid component. The positive effect after longterm operation is more evident in the Jsc parameter. Besides, the use of the polymer electrolyte allows for easier assembly while different types of materials can be used as sealants. 

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