Panchromatic ruthenium sensitizer based on electron-rich heteroarylvinylene ?-conjugated quaterpyridine for dye-sensitized solar cells

The first example of a heteroarylvinylene ?-conjugated quaterpyridine Ru(II) sensitizer (N1044) was synthesized and used in dye-sensitized solar cells; the dye has an effective panchromatic absorption band, covering the entire visible spectrum up to the NIR region, and superior electrochemical characteristics (HOMO/LUMO and bandgap energies) with respect to previous representative Ru(II) bi- and quaterpyridine sensitizers. A record IPCE curve ranging from 360 to 920 nm has been measured with a maximum of 65% at 646 nm and still 33% efficiency at 800 nm; this leads to substantially increased photocurrent (19.2 mA cm-2) when compared to the prototype N719 Ru(II) sensitizer.