Langmuir, Vol.18, No.12, 4553-4555, 2002
Mimicking photosynthetic two-step energy transfer in cyanine triads assembled into capsules
A two-step energy transfer cascade was constructed in the wall of hollow microcapsules by means of defined assembly of three cyanine dyes, thiacyanine (antenna), thiacarbocyanine (receiver and antenna), and indodicarbocyanine (receiver), in the wall plane and perpendicular to it. The efficiency of the energy transfer steps has been measured by fluorescence spectroscopy. The unidirectional energy transfer perpendicular to the surface was smaller than for the lateral one. The antenna dyes on the outer surface of the capsules harvest the light energy and conduct it downhill by Forster resonance energy transfer to the capsule interior in analogy to chloroplasts in nature. However, the obtained efficiency is much smaller, though some improvement was reached by using J-aggregate-forming dyes.