FUNDAMENTALS OF PHOTOELECTRIC EFFECTS IN MOLECULAR ELECTRONIC THIN-FILM DEVICES - APPLICATIONS TO BACTERIORHODOPSIN-BASED DEVICES

This tutorial lecture focuses on the fundamental mechanistic aspects o f light-induced charge movements in pigment-containing membranes. The topic is relevant to molecular electronics because many prototypes opt oelectronic devices are configured as pigment-containing thin films. W e use reconstituted bacteriorhodopsin membranes as an example to illus trate the underlying principle of measurements and data interpretation . Bacteriorhodopsin, a light-driven proton pump, is the only protein c omponent in the purple membrane of Halobacterium halobium. It resemble s the visual pigment rhodopsin chemically but performs the function of photosynthesis. Bacteriorhodopsin thus offers an unprecedented opport unity for us to compare the visual photoreceptor and the photosyntheti c apparatus from a mechanistic point of view. Bacteriorhodopsin, well known for its exceptional chemical and mechanical stability, is also a popular advanced biomaterial for molecular device construction. The t utorial approaches the subject from two angles. First, the fundamental photoelectric properties are exploited for device construction. Secon d, basic design principles for photosensors and photon energy converte rs can be elucidated via 'reverse engineering'. The concept of molecul ar intelligence and the principle of biomimetic science are discussed.