Direct observation of the ultrafast energy transfer in a porphyrin and ruthenium

The luminescence dynamics of a polypyridyl ruthenium II [Ru(phen)2(ip)]2+ and 5,10,15,20-tetraphenylporphyrin (H2TPP) dyad have been measured by using time-resolved fluorescence spectroscopy. The transient luminescent spectra of the dyad show an ultrafast energy transfer within 300 ps after photoexcitation of the [Ru(phen)2(ip)]2+ at 453 nm. However, no energy transfer has been observed as the excitation wavelength is 400 nm, corresponding to the absorption peak of H2TPP. The origin of the energ