What Makes Hydroxamate a Promising Anchoring Group in Dye-Sensitized Solar Cells? Insights from Theoretical Investigation

J Phys Chem Lett. 2014 Nov 20;5(22):3992-9. doi: 10.1021/jz501973d. Epub 2014 Nov 4.

Abstract

We report, from a theoretical point of view, the first comparative study between the highly water-stable hydroxamate and the widely used carboxylate, in addition to the robust phosphate anchors. Theoretical calculations reveal that hydroxamate would be better for photoabsorption. A quantum dynamics description of the interfacial electron transfer (IET), including the underlying nuclear motion effect, is presented. We find that both hydroxamate and carboxylate would have efficient IET character; for phosphate the injection time is significantly longer (several hundred femtoseconds). We also verified that the symmetry of the geometry of the anchoring group plays important roles in the electronic charge delocalization. We conclude that hydroxamate can be a promising anchoring group, as compared to carboxylate and phosphate, due to its better photoabsorption and comparable IET time scale as well as the experimental advantage of water stability. We expect the implications of these findings to be relevant for the design of more efficient anchoring groups for dye-sensitized solar cell (DSSC) application.

Keywords: DSSC; anchoring groups; nuclear dynamics; optical properties; quantum dynamics.