2014 Volume 87 Issue 6 Pages 219-225
The most efficient electric devices in nature will be the light harvesting system in biological membrane. Photosensitive proteins complex, such as photosystem I (PS I), photosystem II (PS II), and electron transport proteins complex such as cytochrome were hierarchically assembled in the bilayer membrane based on their redox potentials. Electrons, which were produced by photoinduced electron transfer in PS II are unidirectionally transferred to cytochrome b6f then PS I following the potential gradient in the membrane. We can produce similar hierarchical molecular assemblies using the Langmuir-Blodgett (LB) technique. The unidirectional electron current flow has been achieved in hierarchical assembled LB films to produce efficient light-energy conversion devices. In this paper, we prepare hierarchical assembled polymer films using the LB technique. It has been reported that poly (N-dodecylacrylamide) forms a stable polymer monolayer “polymer nanosheets” at the air-water interface. Several electrofunctional polymer nanosheets were assembled in a tailor-made manner to achieve the unidirectional electron transfer. We applied the unidirectional electron transfer to produce other unique electrofunctional devices such as molecular memory and mutli-color electrochromism. The results indicate that we can produce unique electric devices by not just mimicking functions in nature but extracting the essence of their functions and applying them.
