Figure 1.

Emission spectra of Tb(III) and Cy3. With a delay time of 100 μs, all signal from the Cy3–Tb(III) sample at 565 nm was attributable to energy transfer from Tb(III) to Cy3 because Tb(III) does not emit at this wavelength. The lifetimes of the contributing components were the lifetimes of the Tb(III) emission in the presence of acceptors. Multiple D–A (donor–acceptor) distances resulted in multiple lifetimes. When recording the emission of Cy3, we did not incorporate the delay time of 0.1 ms used for Tb(III) measurements.