The effect of supercritical carbon dioxide on polymer-solvent mixtures

1994 ◽  
Vol 27 (2) ◽  
pp. 357-364 ◽  
Author(s):  
Anastassios A. Kiamos ◽  
Marc D. Donohue
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Solvent Mixtures ◽  
Polymer Solvent ◽  
Supercritical Carbon

scholarly journals Effect of Solvent, Dye-Loading Time, and Dye Choice on the Performance of Dye-Sensitized Solar Cells

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Fahd M. Rajab
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Film Thickness ◽  
Energy Conversion ◽  
Supercritical Fluid ◽  
Solvent Mixtures ◽  
Dye Sensitized ◽  
Anatase Titania ◽  
Vis Spectroscopy ◽  
Supercritical Carbon

Anatase titania films with a thickness of up to 20 μm and deposited over a fluorine-doped tin-oxide substrate are impregnated with ruthenium dyes N-719 and N-749 using Dip and supercritical-fluid methods for the purpose of fabricating dye-sensitized solar cell devices. The dyes are dissolved in different solvent mixtures, including supercritical carbon dioxide, as well as combinations of more traditional solvents including mixtures of acetonitrile, and t-butanol. Analytical studies included thin-film analyzing and scanning electron microscopy to measure titania film thickness and porosity, UV-Vis spectroscopy to quantify dye concentration, and current-voltage device characterizations to assess energy conversion efficiency, as well as open-circuit voltage decay measurements and quantum efficiency to examine electron collection efficiency. A significant result is that using the dye N-749 in a solvent that includes supercritical carbon dioxide leads to energy conversion efficiencies that are higher for devices with a thick 20 μm semiconductor film than for the case of devices with thinner films, including the 10 μm film thickness that is traditionally considered an upper threshold. The supercritical-fluid method for the N-719 dye also enabled shorter impregnation duration than more conventional classical Dip Methods.

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