Photonic Energy Transport in Phycobilin-Chlorophyll System: A Comparative Study with Artificial Multilayer Films

Abstract

Transport and trapping of electronic excitation-energy have long been the subject of extensive theoretical and experimental works [1,2], Special attention has recently been paid to the excitation energy in some molecular assemblies of some biological systems as well as artificial organizates. Photosynthetic light-harvesting antenna in plants is characterized by highly efficient absorption and subsequent transport of excitation energy to the reaction center. The antenna pigment systems in red and blue-green algae have accessary pigments, phycobilins, as well as chlorophylls, which are attached on thylakoid membranes [3,4]. A schematic illustration of the structure of phycobilizome is shown in Fig. 1(a). Very little is known about the dipole-dipole resonance (Förster-type) energy transfer in restricted molecular geometries such as biological systems and one- and two-dimensional molecular arrangements. In theoretical approaches, the time-dependent equations for the donor fluorescence decay have been proposed for low dimensional systems by HAUSER et al. [5], ZUMOFEN and BLUMEN [6] and BAUMANN and FAYER [7] The present paper is concerned with the sequential energy transfer in the phycobilin-chlorophyll systems in some algae and also in an artificial Langmuir-Blodgett (LB) multilayers as is shown in Fig. 1(b). A comparative study of the sequential energy transfer has been made by means of a picosecond time-resolved fluorescence spectroscopy.