Angular Dependence of Electronic Excitation Energy Transfer Efficiency Between Dye Molecules in a Photonic Crystal

Spectral and luminescent characteristics of a mixture of coumarin 7 and rhodamine B dyes infiltrated into a onedimensional photonic crystal of mesoporous silicon are studied. Electronic excitation energy transfer between molecules that is associated with fluorescence quenching of the donor (coumarin 7) and enhancement of acceptor emission (rhodamine B) is detected. The angular dependence of excitation energy transfer efficiency in the donor–acceptor pair is due to depletion of available photon modes for donor radiative decay in a photonic crystal as compared with a homogeneous medium and depends on the spectral position of the photonic stop zone of a photonic crystal.