Excitation Energy Transfer between a First Generation Dendrimer and a Pyrene Derivative in Langmuir−Blodgett Multilayers

Abstract

A first generation dendrimer D1 was placed onto defined surfaces to study the excitation energy transfer between D1 as donor molecule and a pyrene containing polymer 213 as acceptor molecule in Langmuir−Blodgett (LB) multilayers. Fluorescence experiments were carried out at several excitation wavelengths (220, 260, 312, and 341 nm). D1 formed a closed LB layer with a collapse area of 73 Å 2 on an aqueous subphase, and a successful incorporation of D1 in LB multilayers onto quartz plates was possible. At 220 nm excitation wavelength the adjacent donor and acceptor layers showed a dramatically increased fluorescence activity of the pyrene group in 213, which is about 20 times higher than that of the acceptor layer 213 without the present donor layer D1 . 213 quenches the fluorescence activity of D1 more than 90% although only 5% of the maleic acid groups in 213 are labeled with pyrene. The excitation energy transfer between D1 and 213 may be assumed as a Förster energy transfer which was examined versus distance with two, four, six, and eight interlayers of an amphiphilic copolymer 12 between D1 and 213 .