5.1. Dyes/sensitizers
Three dyes can be considered as the backbone of currently
applied sensitizers in DSC. All of these dyes are ruthenium-
based metal-organic complexes with the general formula
RuLxL.
ySCNz, where L and L.are polypyridyl ligands; they
are readily available commercially and show excellent efficiency
levels up to 11%. The molecular structures of these
dyes are shown in Figure 2. Because of the complex chemical
nomenclature, they are most often referred to with trivial
names as indicated in Figure 2 (N-3 and N-749, which are
commonly also called red and black dyes and Z-907). There
is a widely used variant of the N-3 dye, which differs from it
only in the degree of protonation (trivial name: N-719). The
black dye shows the broadest absorption range up to 900 nm.