Photoinduced charge transfer in molecular materials studied by optical absorption using photoacoustic spectroscopy

Photoacoustic spectra of molecular materials based on the assembling of the [Fe(CN)₆] molecular block were recorded and evaluated. Those compositions where the valence of the involved metals allows a charge transfer (an inner photoinduced redox reaction) through the CN ligand shown an intense photoacoustic signal around 600 nm; when this transition is unable only the signal corresponding to metal-to-ligand and d-d transitions within the metal were observed. This suggests that this technique provides a fast and reliable method to explore the existence of tunable photoinduced charge transfer in molecular materials.