Design of novel efficient sensitizing dye for nanocrystalline solar cell; tripyridine-thiolato (4,,-tricarboxy-2,:,-terpyridine)ruthenium(II)

We have designed tripyridine-thiolato (4, 4 ′ , 4 ″ -tricarboxy-2, 2 ′ : 6 ′ , 2 ″ -terpyridine)ruthenium(II) [complex 1], a novel efficient sensitizing dye for dye sensitized TiO 2 solar cells, based on the DFT MO calculations with PBE0 functional. Complex 1 is a modified BD (black dye: trithiocyanato (4, 4 ′ , 4 ″ -tricarboxy-2, 2 ′ : 6 ′ , 2 ″ -terpyridine)ruthenium(II) complex) molecule where NCS ligands of BD are replaced by C 5 H 4 NS ligands. Molecular and electronic structures of complex 1 have been theoretically characterized. Complex 1 is expected to have the following two advantages over BD, in addition to the advantage of high electron transfer rate from the photoexcited dye to TiO 2 realized in BD: (1) higher electron transfer rate from redox systems to oxidized dyes; (2) higher absorption efficiency to solar spectrum. We propose complex 1 as a novel efficient sensitizing dye which provides the higher efficiency than does BD for dye sensitized solar cells.