Scanning surface potential microscopic studies of photovoltaic Langmuir-Blodgett assemblies containing an A-S-D triad molecule

M. Sakomura^a, T. Oono^b, R. Sakon^b and M. Fujihira^b

a) Department of Physical Chemistry, Yokohama National University
b) Department of Biomolecular Engineering, Tokyo Institute of Technology

Scanning surface potential microscopy (SSPM) was applied to detect the photo-voltaic response of Langmuir-Blodgett (LB) assemblies containing an amphiphilic A-S-D triad molecule. The A-S-D triad acts as a charge separation unit. The photo-induced multi-step electron transfer system is organized in an LB monolayer. The LB assemblies are fabricated by alternate deposition of an A-S-D layer and an additional second donor layer (D') or acceptor layer (A) in the order of A-S-D/D' or A/A-S-D. In these LB assemblies, photo-induced charge separation was performed efficiently due to the longer charge separation distance by the presence of the D' monolayer and lateral diffusion of charges through the D' and A monolayers. The photo-response of LB assemblies including the A-S-D layer together with light harvesting antenna molecules was also studied.