A key event in the function of dye-sensitized solar cells (DSSC) is electron injection from an excited dye molecule into a nanoparticulate wide band gap semiconductor. Efficient injection requires attachment of the dye to the metal oxide surface. Typically, this has been done using carboxylic acid or phosphonic acid groups. Silatranes, which are triethanolamine-protected trialkoxysilane analogs, are versatile, stable silylating agents that may be used to form strong siloxyl bonds to metal oxides. Tetra-arylporphyrins containing carboxylic acid, phosphonic acid, or silatrane groups were synthesized. These molecules were linked to nanoporous TiO2 and the performance of the resulting constructs in DSSC was evaluated. The dyes linked via carboxylate groups formed the densest surface layers and gave the highest external quantum efficiencies. The stabilities of the surface linkages, determined by leaching studies were siloxyl > phosphonate >> carboxylate.

Covalent bonding of molecules to metal oxide semiconductors for dye-sensitized solar cells

244th National Meeting (2012)

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