Nano-materials are materials that are very small (on the order of a nanometer) in at least one dimension (e.g. molecules, tubes/rods and sheets). These materials are of great interest for researchers because they exhibit new and interesting physical and electronic properties compared to those of conventional bulk crystals and because, in many cases, these properties can be tuned by varying the geometry of the material (e.g. changing the diameter of carbon nanotube). For these reasons, there is a large ongoing community effort towards harnessing nano-materials in electronic and optical devices such as photovoltaic and emitting devices. I will discuss my research towards understanding the electronic and optical properties of nano-materials using (and extending) first-principles computational techniques, namely the GW-Bethe-Salpeter-Equation (GWBSE) technique. We discuss the computational challenges surpassed in applying the technique to nano-systems as well as present new physical insight gained through the application of the GWBSE methodology to nano-materials. In particular, we discuss the novel optical properties of single-walled carbon nanotubes, polymer systems and individual graphene sheets. We discuss the scalability of the method on each of these systems and present the prediction of novel physical phenomena - anti-screening - that is unique to nano-materials.
