(404c) Chiral Templating of Self-Assembling Nanostructures By Circularly Polarized Light

Authors: 
Yeom, J., University of Michigan

Materials possessing molecular and nanoscale chirality are well known to rotate the polarization direction of linearly and circularly polarized light (CPL) passing through them. Optical effects related to polarization rotation are relatively easy to observe and have multiple applications. The opposite effects, however, manifesting as the influence of circular polarization of incoming photons on molecular and especially nanometer organization of matter are less known and understood. We believe that it is essential to understand the chemical and physical processes being altered when in response to CPL. If chiral “templation” of organic or inorganic matter with CPL is possible, it can open new synthetic routs to chiral nanostructures, which currently attracting a lot of interest. Self-assembly of NPs is one of the mechanisms that could potentially be influenced by CPL due to chirality of individual NPs, potential amplification of circular polarization effects in them, and sensitivity of self-assembly processes to small changes in interparticle interactions. Following these rationales, here we show that circularly polarized light can drive the self-assembly of cadmium telluride nanoparticles (CdTe NPs) into nanoribbons controlling helical directions by transcription of chiral information from the light to NPs.  Different helical directions of laser induce different light adsorption of CdTe NPs which lead to greater reactivity of a selective chirality. This simple method for chiral nanoribbons can open the door to understanding life’s homochirality and chiroptical devices.