Additives for Increased Photoenergy Conversion Efficiencies of Quasi-Solid, Dye-Sensitized Solar Cells

Abstract

Dye-sensitized solar cells (DSCs) are solidified with gelators containing polyvinylpyridine and 1,2,4,5-tetra(bromomethyl)benzene. The photoconversion efficiencies are improved by new additives. LiI and tt -butylpyridine are commonly added in electrolytes for increasing short-circuit current (Jsc) and open-circuit voltage (Voc). These additives inhibit our gel electrolyte precursors from solidifying. We found that new additives, combinations of acetic acid, and methylpyrimidine or methylbenzimidazole, do not inhibit the solidification and are effective for increasing both Jsc and Voc. These mechanisms are discussed in terms of electron diffusion coefficients, I3−I3− ion diffusion coefficients, and charge-transfer resistances between counter electrodes and gel electrolytes.