Nanoscale Charge Separation Using Chiral Molecules

Abstract

Charge separation is a fundamental process currently being used in a large variety of devices. Typically, charge separation requires doped P/N junctions that, at the nanoscale, are difficult to form due to the small number of participating atoms. Thus, it is not trivial to separate charges at the nanometric scale in a simple flexible way. Recently, studies of electron transfer through organic helical chiral molecules have shown that electron transmission through these molecules is spin-dependent at ambient temperatures. Utilizing semiconductor nanocrystals and helical chiral molecules, we created a room-temperature optically activated, thin-layer, charge-separating nanoscale device. Total efficiency of separation is sensitive to the polarization of the light and could be enhanced by chiral imprinting on the NCs. The fabrication process is simple and uses self-assembly methods that could be applied to a wide variety of nanocrystal-based devices. From the fundamental point of view the induced chiral charge separation may be relevant for physical and biological processes such as charge separation in photosynthesis.