The objective of this research is the fabrication of a working molecular photosensor based on the molecule retinol (vitamin A), precursor of the active chromophore present in animal retinae. The approach is to synthesize a thiolated retinoid, and then attach it as a self assembled monolayer to a gold scanning tunneling microscope tip. The scanning tunneling microscope will allow the retinoid modified tip to be brought into close proximity (< 1nm) to a gold surface; the small distance will allow a tunneling current to pass through the molecule from tip to surface or vice versa. The retinoid bridged tunneling junction will then be irradiated using visible light while the tunneling current is observed; if the excited state of the molecule significantly affects the tunneling current, a photoresponse should be observed. Such a system would constitute a molecular photosensor.
A successful result for the described research would constitute a significant advance in the emerging field of molecular devices and electronics, which could ultimately lead to microscopic cameras, retinal implants, and nanoscale photodetectors that require very little power. The development of these methods will help maintain technical superiority in the critical nanotechnology field. Additionally, this study may enhance knowledge of the behavior of retinoids under completely uninvestigated conditions, which may pave the way to a greater understanding of vision and vision related disorders (an example of which is age-related macular degeneration).
