| 초록 |
The effect of the molecular weight of polymer electrolytes on the overall energy conversion efficiency in solid state DSSCs has been invertigated, because the penetration of the polymer electrolyte into mesoporous TiO2 layer depends on its molecular weight. The overall energy conversion efficiencies have been measured by changing the MW of poly(ethylene glycol) [1k g/mol, 10k g/m, 20k g/mol] and poly(ethylene oxide) [100k g/mol, 1M g/mol]. Where the ionic conductivities of various polymer electrolytes are 1.6×10-4, 1.8×10-5, 1.3×10-5, 2.46×10-5, 7.1×10-5 S/cm, respectively. The penetration of polymer electrolytes with various molecular weight has been chacracterized by FE-SEM. The efficiency monotonically decrease from 1.78 % to 0.0017 % with increasing Mw of polymer electrolyte. The higher efficiency for the low Mw electrolyte is primarily due to the better penetration of the electrolyte into mesoporous TiO2 nanoparticle layer. Therefore, the contact area, through electrons are passed by, between polymer electrolyte and dye adsorbed on the surface TiO2 nanoparticles is increased. Resulting in the increased efficiency of DSSCs. |
