Silica nanoparticle gelled ionic electrolyte for dye sensitized solar cells
Wong, Chee Cheong
Date of Issue2013
School of Materials Science and Engineering
Gelled ionic electrolyte was synthesized with silica nanoparticles and binary ionic liquid electrolyte. Symmetric cells with varied silica contents were tested using electrochemical impedance spectroscopy to study the effect of silica nanoparticles on counter electrode. Dye sensitized solar cells consisting of binary ionic electrolytes with different silica contents were fabricated. I–V test under various light intensities and electrochemical impedance spectroscopy at various biases were conducted to study the effect of silica nanoparticles on charge transfer at the counter electrode/electrolyte interface and on charge transport in the electrolyte. It was observed that charge transfer resistance decreased and electron recombination lifetime increased with the increasing of silica content. Both photocurrent and power conversion efficiency initially decreased and then increased resulting in minimum values at around 9 wt%. This observation could be attributed to the change in dominant charge transport mechanisms: with addition of silica nanoparticles, physical diffusion decreases, while exchange reaction based charge transport in electrolyte is enhanced and the enhancement of exchange reaction overcomes the exacerbation of physical diffusion at around 9 wt%. With the findings above, the charge transport mechanism can be further studied to optimize the efficiency of devices with gelled ionic electrolyte.
Nanoscience and nanotechnology letters
© 2013 American Scientiﬁc Publishers.