  We studied the electron transfer from excitons in adsorbed indoline dye
layers across the organic-inorganic interface. The hybrids consist of indoline
derivatives on the one hand and different inorganic substrates (TiO$_2$, ZnO,
SiO$_2$(0001), fused silica) on the other. We reveal the electron transfer
times from excitons in dye layers to the organic-inorganic interface by
analyzing the photoluminescence transients of the dye layers after femtosecond
excitation and applying kinetic model calculations. A correlation between the
transfer times and four parameters have been found:(i) the number of anchoring
groups, (ii) the distance between the dye and the organic-inorganic interface,
which was varied by the alkyl-chain lengths between the carboxylate anchoring
group and the dye, (iii) the thickness of the adsorbed dye layer, and (iv) the
level alignment between the excited dye ($\pi$*-level) and the conduction band
minimum of the inorganic semiconductor.
