Since O'Regan and Gr�tzel discovered dye-sensitized solar cells in 1991, hundreds of dyes had been designed and tested, and cells with efficiencies of light-to-electric energy conversion as high as 11% for simulated solar light were reported. Most of these dye design efforts have been based on 'guess-and-check' empirical approaches with limited guidance from computational molecular design. Since then, however, attempts to further improve the efficiency of dye-sensitized solar cells have been unsuccessful. Here, we apply a tight-binding linear combination of atomic potential (TB-LCAP) methodology for the inverse design of optimum dye chromophores, based on a phenyl-acetylacetonate (acac) reference adsorbate. This strucuture is a key functional component in a Mn(II)-terpy complex with engineered functions of photo-sensitization and photo-oxidation to Mn2+. By implementing the TB-LCAP optimizations, we find that 3-acac-pyran-2-one is a local optimum structure. It binds strongly to TiO2 surfaces, and has a strong photo-absorption spectrum in the visible range, leading to ultrafast interfacial electron injection. In the literature, related derivatives of 3-acac-pyran-2-one can be linked to coumarin-derived dyes. Supported by the literature evidences and our experimental test, we propose that the 3-acac-pyran-2-one framework could be used as an optimized lead chromophore for practical experimental dye synthesis. For example, by expanding the 3-acac-pyran-2-one p-conjugation using 3 �CH2=CH2- units, a dye-sensitizer can be achieved with more intense visible absorption than that of C343 coumarin dye.

Inverse design of molecular chromophores for dye-sensitized solar cells

240th National Meeting (2010)

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