Center for Functional Nanomaterials Seminar

Nano-scale photonics is one of the key components in future nanotechnology, which plays the central role in novel photovoltaics and solid state lighting. I will talk about our recent research on optoelectronic properties of composite (structurally designed) materials at nm scale for the applications on energy related materials and devices, as well as their integration on a single chip. Utilizing current microelectronics process technology and measurement techniques, it is possible to study these novel energy related devices on an integrated chip in ways that were unimaginable a decade or two ago. In order to improve thin film solar cell efficiency(2nd generation solar cell), we have developed a new light-trapping scheme that can tremendously enhance optical path length and make light almost completely absorbed at NIR wavelength range by using novel photonic materials structure on the backside reflector. It provides extremely high reflectivity with large omnidirectional bandgap over several hundred nanometers in the solar spectrum range. The photonic structure at nano scale can also be utilized to extract light from LEDs, I will give an example on using 2D photonic structure to increase the external quantum efficiency of quantum well structure. Plasmonics is regarded as the photonics at nano scale; the photonic metal materials have combined microelectronics and photonics. Recent work on utilizing the highly localized nature of surface plasmon modes to achieve organic dye emission enhancement, which drastically increase the internal quantum efficiency of the emission layer and leads to the overall LED efficiency enhancement.I will talk about potential challenges to be pursued in these fields that require good control of photons and electrons at nanometer scale. This ability can strongly enhance interaction between electromagnetic field and embedded materials to amplify information and understand fundamental processes affecting optical functionality in nanomaterials.