2-(4-Butoxyphenyl)-N-hydroxyacetamide: An Efficient Preadsorber for Dye-Sensitized Solar Cells

The effect of chemical modification of mesoporous TiO₂ electrodes by 2-(4-butoxyphenyl)-N-hydroxyacetamide (BPHA) before dye adsorption is investigated in dye-sensitized solar cells (DSCs). Two organic dyes, LEG4 and Dyenamo blue, were used in combination with the cobalt (II/III) tris(bipyridine) redox couple. The photovoltaic performance of the DSCs is clearly enhanced by BPHA. Preadsorption of mesoporous TiO₂ electrodes with BPHA lowered the amount of adsorbed dye but improved the short-circuit current densities and the power conversion efficiencies by 10-20%, while keeping the open-circuit potential essentially unaffected. Notably, BPHA improved the LEG4 performance, whereas it has been reported for this dye that chenodeoxycholic acid as a coadsorbent lowers solar cell efficiency. Faster dye regeneration was found to be one reason for improved performance, but improved electron injection efficiency may also contribute to the favorable effect of BPHA.